v4.7.1

Update release notes
fix: fix log output in case of illegal property access
2020-01-12 13:21:08 +01:00 · 2020-01-12 13:20:37 +01:00 · 2020-01-12 13:09:19 +01:00 · 2020-01-12 13:06:56 +01:00 · 2020-01-10 17:24:06 +01:00 · 2020-01-10 17:23:31 +01:00
168 changed files with 23105 additions and 3492 deletions
@@ -0,0 +1,25 @@
+.rvmrc
+.DS_Store
+/tmp/
+*.sublime-project
+*.sublime-workspace
+npm-debug.log
+sauce_connect.log*
+.idea
+yarn-error.log
+node_modules
+/handlebars-release.tgz
+.nyc_output
+
+# Generated files
+lib/handlebars/compiler/parser.js
+/coverage/
+/dist/
+/integration-testing/*/dist/
+
+# Third-party or files that must remain unchanged
+/spec/expected/
+/spec/vendor
+
+# JS-Snippets
+src/*.js
@@ -1,199 +0,0 @@
-{
-  "globals": {
-    "self": false
-  },
-  "env": {
-    "node": true
-  },
-  "ecmaFeatures": {
-    // Enabling features that can be implemented without polyfills. Want to avoid polyfills at this time.
-    "arrowFunctions": true,
-    "blockBindings": true,
-    "defaultParams": true,
-    "destructuring": true,
-    "modules": true,
-    "objectLiteralComputedProperties": true,
-    "objectLiteralDuplicateProperties": true,
-    "objectLiteralShorthandMethods": true,
-    "objectLiteralShorthandProperties": true,
-    "spread": true,
-    "templateStrings": true
-  },
-  "rules": {
-    // Possible Errors //
-    //-----------------//
-
-    "comma-dangle": [2, "never"],
-    "no-cond-assign": [2, "except-parens"],
-
-    // Allow for debugging
-    "no-console": 1,
-
-    "no-constant-condition": 2,
-    "no-control-regex": 2,
-
-    // Allow for debugging
-    "no-debugger": 1,
-
-    "no-dupe-args": 2,
-    "no-dupe-keys": 2,
-    "no-duplicate-case": 2,
-    "no-empty": 2,
-    "no-empty-class": 2,
-    "no-ex-assign": 2,
-    "no-extra-boolean-cast": 2,
-    "no-extra-parens": 0,
-    "no-extra-semi": 2,
-    "no-func-assign": 2,
-
-    // Stylistic... might consider disallowing in the future
-    "no-inner-declarations": 0,
-
-    "no-invalid-regexp": 2,
-    "no-irregular-whitespace": 2,
-    "no-negated-in-lhs": 2,
-    "no-obj-calls": 2,
-    "no-regex-spaces": 2,
-    "no-reserved-keys": 2,    // Important for IE
-    "no-sparse-arrays": 0,
-
-    // Optimizer and coverage will handle/highlight this and can be useful for debugging
-    "no-unreachable": 1,
-
-    "use-isnan": 2,
-    "valid-jsdoc": 0,
-    "valid-typeof": 2,
-
-
-    // Best Practices //
-    //----------------//
-    "block-scoped-var": 0,
-    "complexity": 0,
-    "consistent-return": 0,
-    "curly": 2,
-    "default-case": 1,
-    "dot-notation": [2, {"allowKeywords": false}],
-    "eqeqeq": 0,
-    "guard-for-in": 1,
-    "no-alert": 2,
-    "no-caller": 2,
-    "no-div-regex": 1,
-    "no-else-return": 0,
-    "no-empty-label": 2,
-    "no-eq-null": 0,
-    "no-eval": 2,
-    "no-extend-native": 2,
-    "no-extra-bind": 2,
-    "no-fallthrough": 2,
-    "no-floating-decimal": 2,
-    "no-implied-eval": 2,
-    "no-iterator": 2,
-    "no-labels": 2,
-    "no-lone-blocks": 2,
-    "no-loop-func": 2,
-    "no-multi-spaces": 2,
-    "no-multi-str": 1,
-    "no-native-reassign": 2,
-    "no-new": 2,
-    "no-new-func": 2,
-    "no-new-wrappers": 2,
-    "no-octal": 2,
-    "no-octal-escape": 2,
-    "no-param-reassign": 0,
-    "no-process-env": 2,
-    "no-proto": 2,
-    "no-redeclare": 2,
-    "no-return-assign": 2,
-    "no-script-url": 2,
-    "no-self-compare": 2,
-    "no-sequences": 2,
-    "no-throw-literal": 2,
-    "no-unused-expressions": 2,
-    "no-void": 0,
-    "no-warning-comments": 1,
-    "no-with": 2,
-    "radix": 2,
-    "vars-on-top": 0,
-    "wrap-iife": 2,
-    "yoda": 0,
-
-
-    // Strict //
-    //--------//
-    "strict": 0,
-
-
-    // Variables //
-    //-----------//
-    "no-catch-shadow": 2,
-    "no-delete-var": 2,
-    "no-label-var": 2,
-    "no-shadow": 2,
-    "no-shadow-restricted-names": 2,
-    "no-undef": 2,
-    "no-undef-init": 2,
-    "no-undefined": 0,
-    "no-unused-vars": [2, {"vars": "all", "args": "after-used"}],    
-    "no-use-before-define": [2, "nofunc"],
-
-
-    // Node.js //
-    //---------//
-    // Others left to environment defaults
-    "no-mixed-requires": 0,
-
-
-    // Stylistic //
-    //-----------//
-    "indent": 0,
-    "brace-style": [2, "1tbs", {"allowSingleLine": true}],
-    "camelcase": 2,
-    "comma-spacing": [2, {"before": false, "after": true}],
-    "comma-style": [2, "last"],
-    "consistent-this": [1, "self"],
-    "eol-last": 2,
-    "func-names": 0,
-    "func-style": [2, "declaration"],
-    "key-spacing": [2, {
-        "beforeColon": false,
-        "afterColon": true
-    }],
-    "max-nested-callbacks": 0,
-    "new-cap": 2,
-    "new-parens": 2,
-    "newline-after-var": 0,
-    "no-array-constructor": 2,
-    "no-continue": 0,
-    "no-inline-comments": 0,
-    "no-lonely-if": 2,
-    "no-mixed-spaces-and-tabs": 2,
-    "no-multiple-empty-lines": 0,
-    "no-nested-ternary": 1,
-    "no-new-object": 2,
-    "no-spaced-func": 2,
-    "no-ternary": 0,
-    "no-trailing-spaces": 2,
-    "no-underscore-dangle": 0,
-    "no-wrap-func": 2,
-    "one-var": 0,
-    "operator-assignment": 0,
-    "padded-blocks": 0,
-    "quote-props": 0,
-    "quotes": [2, "single", "avoid-escape"],
-    "semi": 2,
-    "semi-spacing": [2, {"before": false, "after": true}],
-    "sort-vars": 0,
-    "space-after-keywords": [2, "always"],
-    "space-before-blocks": [2, "always"],
-    "space-before-function-paren": [2, {"anonymous": "never", "named": "never"}],
-    "space-in-brackets": 0,
-    "space-in-parens": [2, "never"],
-    "space-infix-ops": 2,
-    "space-return-throw-case": 2,
-    "space-unary-ops": 2,
-    "spaced-line-comment": 2,
-    "wrap-regex": 1,
-
-    "no-var": 1
-  }
-}
@@ -0,0 +1,66 @@
+module.exports = {
+  extends: ['eslint:recommended', 'plugin:compat/recommended', 'prettier'],
+  globals: {
+    self: false
+  },
+  env: {
+    node: true,
+    es6: true
+  },
+  rules: {
+    'no-console': 'warn',
+
+    // temporarily disabled until the violating places are fixed.
+    'no-func-assign': 'off',
+    'no-sparse-arrays': 'off',
+
+    // Best Practices //
+    //----------------//
+    'default-case': 'warn',
+    'guard-for-in': 'warn',
+    'no-alert': 'error',
+    'no-caller': 'error',
+    'no-div-regex': 'warn',
+    'no-eval': 'error',
+    'no-extend-native': 'error',
+    'no-extra-bind': 'error',
+    'no-floating-decimal': 'error',
+    'no-implied-eval': 'error',
+    'no-iterator': 'error',
+    'no-labels': 'error',
+    'no-lone-blocks': 'error',
+    'no-loop-func': 'error',
+    'no-multi-str': 'warn',
+    'no-global-assign': 'error',
+    'no-new': 'error',
+    'no-new-func': 'error',
+    'no-new-wrappers': 'error',
+    'no-octal-escape': 'error',
+    'no-process-env': 'error',
+    'no-proto': 'error',
+    'no-return-assign': 'error',
+    'no-script-url': 'error',
+    'no-self-compare': 'error',
+    'no-sequences': 'error',
+    'no-throw-literal': 'error',
+    'no-unused-expressions': 'error',
+    'no-warning-comments': 'warn',
+    'no-with': 'error',
+    radix: 'error',
+
+    // Variables //
+    //-----------//
+    'no-label-var': 'error',
+    'no-undef-init': 'error',
+    'no-use-before-define': ['error', 'nofunc'],
+
+    // ECMAScript 6 //
+    //--------------//
+    'no-var': 'error'
+  },
+  parserOptions: {
+    sourceType: 'module',
+    ecmaVersion: 6,
+    ecmaFeatures: {}
+  }
+};
@@ -0,0 +1,6 @@
+# Handlebars-template fixtures in test cases need deterministic eol
+*.handlebars text eol=lf
+*.hbs text eol=lf
+
+# Lexer files as well
+*.l text eol=lf
@@ -1,12 +1,19 @@
-vendor
 .rvmrc
 .DS_Store
-lib/handlebars/compiler/parser.js
-/dist/
 /tmp/
-/coverage/
-node_modules
 *.sublime-project
 *.sublime-workspace
 npm-debug.log
 sauce_connect.log*
+.idea
+/yarn-error.log
+/yarn.lock
+node_modules
+/handlebars-release.tgz
+.nyc_output
+
+# Generated files
+lib/handlebars/compiler/parser.js
+/coverage/
+/dist/
+/integration-testing/*/dist/
@@ -1,2 +0,0 @@
-instrumentation:
-    excludes: ['**/spec/**']
@@ -1,25 +0,0 @@
-.DS_Store
-.gitignore
-.rvmrc
-.eslintrc
-.travis.yml
-.rspec
-Gemfile
-Gemfile.lock
-Rakefile
-Gruntfile.js
-*.gemspec
-*.nuspec
-*.log
-bench/*
-configurations/*
-components/*
-coverage/*
-dist/cdnjs/*
-dist/components/*
-spec/*
-src/*
-tasks/*
-tmp/*
-publish/*
-vendor/*
@@ -0,0 +1,22 @@
+.rvmrc
+.DS_Store
+/tmp/
+*.sublime-project
+*.sublime-workspace
+npm-debug.log
+sauce_connect.log*
+.idea
+yarn-error.log
+node_modules
+/handlebars-release.tgz
+.nyc_output
+
+# Generated files
+lib/handlebars/compiler/parser.js
+/coverage/
+/dist/
+/integration-testing/*/dist/
+
+# Third-party or files that must remain unchanged
+/spec/expected/
+/spec/vendor
@@ -1,23 +1,39 @@
 language: node_js
-before_install:
- npm install -g grunt-cli
-script:
- grunt --stack travis
+jobs:
+  include:
+  - stage: test
+    name: check javascript (eslint)
+    node_js: lts/*
+    script: npm run lint
+  - stage: test
+    name: check formatting (prettier)
+    node_js: lts/*
+    script: npm run check-format
+  - stage: test
+    name: check typescript definitions (dtslint)
+    node_js: lts/*
+    script: npm run dtslint
+  - stage: test
+    name: extensive tests and publish to aws
+    script: npm run extensive-tests-and-publish-to-aws
+    env:
+    - S3_BUCKET_NAME=builds.handlebarsjs.com
+    - secure: ckyEe5dzjdFDjmZ6wIrhGm0CFBEnKq8c1dYptfgVV/Q5/nJFGzu8T0yTjouS/ERxzdT2H327/63VCxhFnLCRHrsh4rlW/rCy4XI3O/0TeMLgFPa4TXkO8359qZ4CB44TBb3NsJyQXNMYdJpPLTCVTMpuiqqkFFOr+6OeggR7ufA=
+    - secure: Nm4AgSfsgNB21kgKrF9Tl7qVZU8YYREhouQunFracTcZZh2NZ2XH5aHuSiXCj88B13Cr/jGbJKsZ4T3QS3wWYtz6lkyVOx3H3iI+TMtqhD9RM3a7A4O+4vVN8IioB2YjhEu0OKjwgX5gp+0uF+pLEi7Hpj6fupD3AbbL5uYcKg8=
+    - SAUCE_USERNAME=handlebars
+    - secure: 1VkLQhbsEug4ZMQ52tTOus/WLvW3Etqe7GbCzZfzsI8d2ygJPjFfzU8fNm4pVVwoTI21MaM5AQq7SVPu8DWN1YbDjJycMdY1zO3DsB9aZBxTal98fIB7ZIUce9r5z2EP6mETrsbYjZkeckzIBI0A4UVa+F2BO4KbRDXP1Db3u3I=
+    node_js: '10'
+  - stage: test
+    name: test with latest nodejs-lts
+    node_js: lts/*
+    script: npm run test
+  - stage: test
+    name: test with active nodejs
+    node_js: node
+    script: npm run test
+cache: npm
 email:
  on_failure: change
  on_success: never
-env:
-  global:
-  - S3_BUCKET_NAME=builds.handlebarsjs.com
-  - secure: ckyEe5dzjdFDjmZ6wIrhGm0CFBEnKq8c1dYptfgVV/Q5/nJFGzu8T0yTjouS/ERxzdT2H327/63VCxhFnLCRHrsh4rlW/rCy4XI3O/0TeMLgFPa4TXkO8359qZ4CB44TBb3NsJyQXNMYdJpPLTCVTMpuiqqkFFOr+6OeggR7ufA=
-  - secure: Nm4AgSfsgNB21kgKrF9Tl7qVZU8YYREhouQunFracTcZZh2NZ2XH5aHuSiXCj88B13Cr/jGbJKsZ4T3QS3wWYtz6lkyVOx3H3iI+TMtqhD9RM3a7A4O+4vVN8IioB2YjhEu0OKjwgX5gp+0uF+pLEi7Hpj6fupD3AbbL5uYcKg8=
-matrix:
-  include:
-  - node_js: '0.10'
-    env:
-    - PUBLISH=true
-    - secure: pLTzghtVll9yGKJI0AaB0uI8GypfWxLTaIB0ZL8//yN3nAEIKMhf/RRilYTsn/rKj2NUa7vt2edYILi3lttOUlCBOwTc9amiRms1W8Lwr/3IdWPeBLvLuH1zNJRm2lBAwU4LBSqaOwhGaxOQr6KHTnWudhNhgOucxpZfvfI/dFw=
-    - secure: yERYCf7AwL11D9uMtacly/THGV8BlzsMmrt+iQVvGA3GaY6QMmfYqf6P6cCH98sH5etd1Y+1e6YrPeMjqI6lyRllT7FptoyOdHulazQe86VQN4sc0EpqMlH088kB7gGjTut9Z+X9ViooT5XEh9WA5jXEI9pXhQJNoIHkWPuwGuY=
-cache:
-  directories:
-  - node_modules
+git:
+  depth: 100
@@ -6,15 +6,22 @@ Please see our [FAQ](https://github.com/wycats/handlebars.js/blob/master/FAQ.md)

 Should you run into other issues with the project, please don't hesitate to let us know by filing an [issue][issue]! In general we are going to ask for an example of the problem failing, which can be as simple as a jsfiddle/jsbin/etc. We've put together a jsfiddle [template][jsfiddle] to ease this. (We will keep this link up to date as new releases occur, so feel free to check back here)

-Pull requests containing only failing thats demonstrating the issue are welcomed and this also helps ensure that your issue won't regress in the future once it's fixed.
+Pull requests containing only failing tests demonstrating the issue are welcomed and this also helps ensure that your issue won't regress in the future once it's fixed.

 Documentation issues on the handlebarsjs.com site should be reported on [handlebars-site](https://github.com/wycats/handlebars-site).

+## Branches
+
+- The branch `4.x` contains the currently released version. Bugfixes should be made in this branch.
+- The branch `master` contains the next version. A release date is not yet specified. Maintainers
+  should merge the branch `4.x` into the master branch regularly.
+
 ## Pull Requests

 We also accept [pull requests][pull-request]!

 Generally we like to see pull requests that
+
 - Maintain the existing code style
 - Are focused on a single change (i.e. avoid large refactoring or style adjustments in untouched code if not the primary goal of the pull request)
 - Have [good commit messages](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html)
@@ -25,8 +32,8 @@ Generally we like to see pull requests that

 To build Handlebars.js you'll need a few things installed.

-* Node.js
-* [Grunt](http://gruntjs.com/getting-started)
+- Node.js
+- [Grunt](http://gruntjs.com/getting-started)

 Before building, you need to make sure that the Git submodule `spec/mustache` is included (i.e. the directory `spec/mustache` should not be empty). To include it, if using Git version 1.6.5 or newer, use `git clone --recursive` rather than `git clone`. Or, if you already cloned without `--recursive`, use `git submodule update --init`.

@@ -42,6 +49,46 @@ The `grunt dev` implements watching for tests and allows for in browser testing
 If you notice any problems, please report them to the GitHub issue tracker at
 [http://github.com/wycats/handlebars.js/issues](http://github.com/wycats/handlebars.js/issues).

+##Running Tests
+
+To run tests locally, first install all dependencies.
+
+```sh
+npm install
+```
+
+Clone the mustache specs into the spec/mustache folder.
+
+```sh
+cd spec
+rm -r mustache
+git clone https://github.com/mustache/spec.git mustache
+```
+
+From the root directory, run the tests.
+
+```sh
+npm test
+```
+
+## Linting and Formatting
+
+Handlebars uses `eslint` to enforce best-practices and `prettier` to auto-format files.
+We do linting and formatting in two phases:
+
+- Committed files are linted and formatted in a pre-commit hook. In this stage eslint-errors are forbidden,
+  while warnings are allowed.
+- The travis-ci job also lints all files and checks if they are formatted correctly. In this stage, warnings
+  are forbidden.
+
+You can use the following scripts to make sure that the travis-job does not fail:
+
+- **npm run lint** will run `eslint` and fail on warnings
+- **npm run format** will run `prettier` on all files
+- **npm run check-before-pull-request** will perform all most checks that travis does in its build-job, excluding the "integration-test".
+- **npm run integration-test** will run integration tests (using old NodeJS versions and integrations with webpack, babel and so on)
+  These tests only work on a Linux-machine with `nvm` installed (for running tests in multiple versions of NodeJS).
+
 ## Ember testing

 The current ember distribution should be tested as part of the handlebars release process. This requires building the `handlebars-source` gem locally and then executing the ember test script.
@@ -56,13 +103,16 @@ npm link handlebars
 npm test
 ```

-## Releasing
+## Releasing the latest version
+
+_When releasing a previous version of Handlebars, please look into the CONTRIBUNG.md in the corresponding branch._

 Handlebars utilizes the [release yeoman generator][generator-release] to perform most release tasks.

 A full release may be completed with the following:

 ```
+npm ci
 yo release
 npm publish
 yo release:publish components handlebars.js dist/components/
@@ -72,9 +122,17 @@ gem build handlebars-source.gemspec
 gem push handlebars-source-*.gem
 ```

-After this point the handlebars site needs to be updated to point to the new version numbers. The jsfiddle link should be updated to point to the most recent distribution for all instances in our documentation.
+After the release, you should check that all places have really been updated. Especially verify that the `latest`-tags
+in those places still point to the latest version
+
+- [The npm-package](https://www.npmjs.com/package/handlebars) (check latest-tag)
+- [The bower package](https://github.com/components/handlebars.js) (check the package.json)
+- [The AWS S3 Bucket](https://s3.amazonaws.com/builds.handlebarsjs.com) (check latest-tag)
+- [RubyGems](https://rubygems.org/gems/handlebars-source)
+
+When everything is OK, the handlebars site needs to be updated to point to the new version numbers. The jsfiddle link should be updated to point to the most recent distribution for all instances in our documentation.

 [generator-release]: https://github.com/walmartlabs/generator-release
 [pull-request]: https://github.com/wycats/handlebars.js/pull/new/master
 [issue]: https://github.com/wycats/handlebars.js/issues/new
-[jsfiddle]: http://jsfiddle.net/9D88g/26/
+[jsfiddle]: https://jsfiddle.net/9D88g/180/
@@ -1,72 +1,78 @@
-/*eslint-disable no-process-env */
+/* eslint-disable no-process-env */
 module.exports = function(grunt) {
-
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),

-    eslint: {
-      options: {
-      },
-      files: [
-        '*.js',
-        'lib/**/!(*.min|parser).js',
-        'spec/**/!(*.amd|json2|require).js'
-      ]
-    },
-
-    clean: ['tmp', 'dist', 'lib/handlebars/compiler/parser.js'],
+    clean: [
+      'tmp',
+      'dist',
+      'lib/handlebars/compiler/parser.js',
+      'integration-testing/**/node_modules'
+    ],

    copy: {
      dist: {
        options: {
          processContent: function(content) {
-            return grunt.template.process('/*!\n\n <%= pkg.name %> v<%= pkg.version %>\n\n<%= grunt.file.read("LICENSE") %>\n@license\n*/\n')
-                + content;
+            return (
+              grunt.template.process(
+                '/**!\n\n @license\n <%= pkg.name %> v<%= pkg.version %>\n\n<%= grunt.file.read("LICENSE") %>\n*/\n'
+              ) + content
+            );
          }
        },
-        files: [
-          {expand: true, cwd: 'dist/', src: ['*.js'], dest: 'dist/'}
-        ]
+        files: [{ expand: true, cwd: 'dist/', src: ['*.js'], dest: 'dist/' }]
      },
      cdnjs: {
        files: [
-          {expand: true, cwd: 'dist/', src: ['*.js'], dest: 'dist/cdnjs'}
+          { expand: true, cwd: 'dist/', src: ['*.js'], dest: 'dist/cdnjs' }
        ]
      },
      components: {
        files: [
-          {expand: true, cwd: 'components/', src: ['**'], dest: 'dist/components'},
-          {expand: true, cwd: 'dist/', src: ['*.js'], dest: 'dist/components'}
+          {
+            expand: true,
+            cwd: 'components/',
+            src: ['**'],
+            dest: 'dist/components'
+          },
+          { expand: true, cwd: 'dist/', src: ['*.js'], dest: 'dist/components' }
        ]
      }
    },

    babel: {
      options: {
-        loose: ['es6.modules']
+        sourceMaps: 'inline',
+        loose: ['es6.modules'],
+        auxiliaryCommentBefore: 'istanbul ignore next'
      },
      amd: {
        options: {
          modules: 'amd'
        },
-        files: [{
-          expand: true,
-          cwd: 'lib/',
-          src: '**/!(index).js',
-          dest: 'dist/amd/'
-        }]
+        files: [
+          {
+            expand: true,
+            cwd: 'lib/',
+            src: '**/!(index).js',
+            dest: 'dist/amd/'
+          }
+        ]
      },

      cjs: {
        options: {
          modules: 'common'
        },
-        files: [{
-          cwd: 'lib/',
-          expand: true,
-          src: '**/!(index).js',
-          dest: 'dist/cjs/'
-        }]
+        files: [
+          {
+            cwd: 'lib/',
+            expand: true,
+            src: '**/!(index).js',
+            dest: 'dist/cjs/'
+          }
+        ]
      }
    },
    webpack: {
@@ -75,7 +81,12 @@ module.exports = function(grunt) {
        module: {
          loaders: [
            // the optional 'runtime' transformer tells babel to require the runtime instead of inlining it.
-            { test: /\.jsx?$/, exclude: /node_modules/, loader: 'babel-loader?optional=runtime&loose=es6.modules' }
+            {
+              test: /\.jsx?$/,
+              exclude: /node_modules/,
+              loader:
+                'babel-loader?optional=runtime&loose=es6.modules&auxiliaryCommentBefore=istanbul%20ignore%20next'
+            }
          ]
        },
        output: {
@@ -121,18 +132,20 @@ module.exports = function(grunt) {
      options: {
        mangle: true,
        compress: true,
-        preserveComments: 'some'
+        preserveComments: /(?:^!|@(?:license|preserve|cc_on))/
      },
      dist: {
-        files: [{
-          cwd: 'dist/',
-          expand: true,
-          src: ['handlebars*.js', '!*.min.js'],
-          dest: 'dist/',
-          rename: function(dest, src) {
-            return dest + src.replace(/\.js$/, '.min.js');
+        files: [
+          {
+            cwd: 'dist/',
+            expand: true,
+            src: ['handlebars*.js', '!*.min.js'],
+            dest: 'dist/',
+            rename: function(dest, src) {
+              return dest + src.replace(/\.js$/, '.min.js');
+            }
          }
-        }]
+        ]
      }
    },

@@ -156,33 +169,53 @@ module.exports = function(grunt) {
      all: {
        options: {
          build: process.env.TRAVIS_JOB_ID,
-          urls: ['http://localhost:9999/spec/?headless=true', 'http://localhost:9999/spec/amd.html?headless=true'],
+          urls: [
+            'http://localhost:9999/spec/?headless=true',
+            'http://localhost:9999/spec/amd.html?headless=true'
+          ],
          detailedError: true,
-          concurrency: 2,
+          concurrency: 4,
          browsers: [
-            {browserName: 'chrome'},
-            {browserName: 'firefox'},
-            {browserName: 'safari', version: 7, platform: 'OS X 10.9'},
-            {browserName: 'safari', version: 6, platform: 'OS X 10.8'},
-            {browserName: 'internet explorer', version: 11, platform: 'Windows 8.1'},
-            {browserName: 'internet explorer', version: 10, platform: 'Windows 8'},
-            {browserName: 'internet explorer', version: 9, platform: 'Windows 7'}
+            { browserName: 'chrome' },
+            { browserName: 'firefox', platform: 'Linux' },
+            // {browserName: 'safari', version: 9, platform: 'OS X 10.11'},
+            // {browserName: 'safari', version: 8, platform: 'OS X 10.10'},
+            {
+              browserName: 'internet explorer',
+              version: 11,
+              platform: 'Windows 8.1'
+            },
+            {
+              browserName: 'internet explorer',
+              version: 10,
+              platform: 'Windows 8'
+            }
          ]
        }
      },
      sanity: {
        options: {
          build: process.env.TRAVIS_JOB_ID,
-          urls: ['http://localhost:9999/spec/umd.html?headless=true', 'http://localhost:9999/spec/amd-runtime.html?headless=true', 'http://localhost:9999/spec/umd-runtime.html?headless=true'],
+          urls: [
+            'http://localhost:9999/spec/umd.html?headless=true',
+            'http://localhost:9999/spec/amd-runtime.html?headless=true',
+            'http://localhost:9999/spec/umd-runtime.html?headless=true'
+          ],
          detailedError: true,
          concurrency: 2,
-          browsers: [
-            {browserName: 'chrome'}
-          ]
+          browsers: [{ browserName: 'chrome' }]
        }
      }
    },

+    bgShell: {
+      integrationTests: {
+        cmd: './integration-testing/run-integration-tests.sh',
+        bg: false,
+        fail: true
+      }
+    },
+
    watch: {
      scripts: {
        options: {
@@ -190,25 +223,11 @@ module.exports = function(grunt) {
        },

        files: ['src/*', 'lib/**/*.js', 'spec/**/*.js'],
-        tasks: ['build', 'amd', 'tests', 'test']
+        tasks: ['on-file-change']
      }
    }
  });

-  // Build a new version of the library
-  this.registerTask('build', 'Builds a distributable version of the current project', [
-                    'eslint',
-                    'parser',
-                    'node',
-                    'globals']);
-
-  this.registerTask('amd', ['babel:amd', 'requirejs']);
-  this.registerTask('node', ['babel:cjs']);
-  this.registerTask('globals', ['webpack']);
-  this.registerTask('tests', ['concat:tests']);
-
-  this.registerTask('release', 'Build final packages', ['eslint', 'amd', 'uglify', 'copy:dist', 'copy:components', 'copy:cdnjs']);
-
  // Load tasks from npm
  grunt.loadNpmTasks('grunt-contrib-clean');
  grunt.loadNpmTasks('grunt-contrib-concat');
@@ -218,17 +237,62 @@ module.exports = function(grunt) {
  grunt.loadNpmTasks('grunt-contrib-uglify');
  grunt.loadNpmTasks('grunt-contrib-watch');
  grunt.loadNpmTasks('grunt-babel');
-  grunt.loadNpmTasks('grunt-eslint');
-  grunt.loadNpmTasks('grunt-saucelabs');
+  grunt.loadNpmTasks('grunt-bg-shell');
+  grunt.loadNpmTasks('@knappi/grunt-saucelabs');
  grunt.loadNpmTasks('grunt-webpack');

  grunt.task.loadTasks('tasks');

+  this.registerTask(
+    'build',
+    'Builds a distributable version of the current project',
+    ['parser', 'node', 'globals']
+  );
+
+  this.registerTask('node', ['babel:cjs']);
+  this.registerTask('globals', ['webpack']);
+
+  this.registerTask('release', 'Build final packages', [
+    'amd',
+    'uglify',
+    'test:min',
+    'copy:dist',
+    'copy:components',
+    'copy:cdnjs'
+  ]);
+
+  this.registerTask('amd', ['babel:amd', 'requirejs']);
+
+  this.registerTask('test', ['test:bin', 'test:cov']);
+
  grunt.registerTask('bench', ['metrics']);
-  grunt.registerTask('sauce', process.env.SAUCE_USERNAME ? ['tests', 'connect', 'saucelabs-mocha'] : []);

-  grunt.registerTask('travis', process.env.PUBLISH ? ['default', 'sauce', 'metrics', 'publish:latest'] : ['default']);
+  if (process.env.SAUCE_USERNAME) {
+    grunt.registerTask('sauce', ['concat:tests', 'connect', 'saucelabs-mocha']);
+  } else {
+    grunt.registerTask('sauce', []);
+  }

+  // Requires secret properties (saucelabs-credentials etc.) from .travis.yaml
+  grunt.registerTask('extensive-tests-and-publish-to-aws', [
+    'default',
+    'bgShell:integrationTests',
+    'sauce',
+    'metrics',
+    'publish-to-aws'
+  ]);
+  grunt.registerTask('on-file-change', [
+    'build',
+    'amd',
+    'concat:tests',
+    'test'
+  ]);
+
+  // === Primary tasks ===
  grunt.registerTask('dev', ['clean', 'connect', 'watch']);
  grunt.registerTask('default', ['clean', 'build', 'test', 'release']);
+  grunt.registerTask('integration-tests', [
+    'default',
+    'bgShell:integrationTests'
+  ]);
 };
@@ -1,4 +1,4 @@
-Copyright (C) 2011-2014 by Yehuda Katz
+Copyright (C) 2011-2019 by Yehuda Katz

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -1,4 +1,5 @@
 [![Travis Build Status](https://img.shields.io/travis/wycats/handlebars.js/master.svg)](https://travis-ci.org/wycats/handlebars.js)
+[![Appveyor Build Status](https://ci.appveyor.com/api/projects/status/github/wycats/handlebars.js?branch=master&svg=true)](https://ci.appveyor.com/project/wycats/handlebars-js)
 [![Selenium Test Status](https://saucelabs.com/buildstatus/handlebars)](https://saucelabs.com/u/handlebars)

 Handlebars.js
@@ -10,24 +11,12 @@ Handlebars.js and Mustache are both logicless templating languages that
 keep the view and the code separated like we all know they should be.

 Checkout the official Handlebars docs site at
-[http://www.handlebarsjs.com](http://www.handlebarsjs.com).
+[https://handlebarsjs.com/](https://handlebarsjs.com) and the live demo at [http://tryhandlebarsjs.com/](http://tryhandlebarsjs.com/).

 Installing
 ----------
-Installing Handlebars is easy. Simply download the package [from the official site](http://handlebarsjs.com/) or the [bower repository][bower-repo] and add it to your web pages (you should usually use the most recent version).

-For web browsers, a free CDN is available at [jsDelivr](http://www.jsdelivr.com/#!handlebarsjs).  Advanced usage, such as [version aliasing & concocting](https://github.com/jsdelivr/jsdelivr#usage), is available. 
-
-Alternatively, if you prefer having the latest version of handlebars from
-the 'master' branch, passing builds of the 'master' branch are automatically
-published to S3. You may download the latest passing master build by grabbing
-a `handlebars-latest.js` file from the [builds page][builds-page]. When the
-build is published, it is also available as a `handlebars-gitSHA.js` file on
-the builds page if you need a version to refer to others.
-`handlebars-runtime.js` builds are also available.
-
-**Note**: The S3 builds page is provided as a convenience for the community,
-but you should not use it for hosting Handlebars in production.
+See our [installation documentation](https://handlebarsjs.com/installation/).

 Usage
 -----
@@ -57,295 +46,34 @@ var result = template(data);
 // </ul>
 ```

+Full documentation and more examples are at [handlebarsjs.com](https://handlebarsjs.com/).

-Registering Helpers
-------------------
-
-You can register helpers that Handlebars will use when evaluating your
-template. Here's an example, which assumes that your objects have a URL
-embedded in them, as well as the text for a link:
-
-```js
-Handlebars.registerHelper('link_to', function() {
-  return new Handlebars.SafeString("<a href='" + Handlebars.Utils.escapeExpression(this.url) + "'>" + Handlebars.Utils.escapeExpression(this.body) + "</a>");
-});
-
-var context = { posts: [{url: "/hello-world", body: "Hello World!"}] };
-var source = "<ul>{{#posts}}<li>{{link_to}}</li>{{/posts}}</ul>"
-
-var template = Handlebars.compile(source);
-template(context);
-
-// Would render:
-//
-// <ul>
-//   <li><a href='/hello-world'>Hello World!</a></li>
-// </ul>
-```
-
-Helpers take precedence over fields defined on the context. To access a field
-that is masked by a helper, a path reference may be used. In the example above
-a field named `link_to` on the `context` object would be referenced using:
-
-```
-{{./link_to}}
-```
-
-Escaping
--------
-
-By default, the `{{expression}}` syntax will escape its contents. This
-helps to protect you against accidental XSS problems caused by malicious
-data passed from the server as JSON.
-
-To explicitly *not* escape the contents, use the triple-mustache
-(`{{{}}}`). You have seen this used in the above example.
+Precompiling Templates
+----------------------

+Handlebars allows templates to be precompiled and included as javascript code rather than the handlebars template allowing for faster startup time. Full details are located [here](https://handlebarsjs.com/installation/precompilation.html).

 Differences Between Handlebars.js and Mustache
 ----------------------------------------------
 Handlebars.js adds a couple of additional features to make writing
 templates easier and also changes a tiny detail of how partials work.

-### Paths
-
-Handlebars.js supports an extended expression syntax that we call paths.
-Paths are made up of typical expressions and `.` characters. Expressions
-allow you to not only display data from the current context, but to
-display data from contexts that are descendants and ancestors of the
-current context.
-
-To display data from descendant contexts, use the `.` character. So, for
-example, if your data were structured like:
-
-```js
-var data = {"person": { "name": "Alan" }, "company": {"name": "Rad, Inc." } };
-```
-
-You could display the person's name from the top-level context with the
-following expression:
-
-```
-{{person.name}}
-```
-
-You can backtrack using `../`. For example, if you've already traversed
-into the person object you could still display the company's name with
-an expression like `{{../company.name}}`, so:
-
-```
-{{#with person}}{{name}} - {{../company.name}}{{/with}}
-```
-
-would render:
-
-```
-Alan - Rad, Inc.
-```
-
-### Strings
-
-When calling a helper, you can pass paths or Strings as parameters. For
-instance:
-
-```js
-Handlebars.registerHelper('link_to', function(title, options) {
-  return "<a href='/posts" + this.url + "'>" + title + "!</a>"
-});
-
-var context = { posts: [{url: "/hello-world", body: "Hello World!"}] };
-var source = '<ul>{{#posts}}<li>{{{link_to "Post"}}}</li>{{/posts}}</ul>'
-
-var template = Handlebars.compile(source);
-template(context);
-
-// Would render:
-//
-// <ul>
-//   <li><a href='/posts/hello-world'>Post!</a></li>
-// </ul>
-```
-
-When you pass a String as a parameter to a helper, the literal String
-gets passed to the helper function.
-
-
-### Block Helpers
-
-Handlebars.js also adds the ability to define block helpers. Block
-helpers are functions that can be called from anywhere in the template.
-Here's an example:
-
-```js
-var source = "<ul>{{#people}}<li>{{#link}}{{name}}{{/link}}</li>{{/people}}</ul>";
-Handlebars.registerHelper('link', function(options) {
-  return '<a href="/people/' + this.id + '">' + options.fn(this) + '</a>';
-});
-var template = Handlebars.compile(source);
-
-var data = { "people": [
-    { "name": "Alan", "id": 1 },
-    { "name": "Yehuda", "id": 2 }
-  ]};
-template(data);
-
-// Should render:
-// <ul>
-//   <li><a href="/people/1">Alan</a></li>
-//   <li><a href="/people/2">Yehuda</a></li>
-// </ul>
-```
-
-Whenever the block helper is called it is given one or more parameters,
-any arguments that are passed into the helper in the call, and an `options`
-object containing the `fn` function which executes the block's child.
-The block's current context may be accessed through `this`.
-
-Block helpers have the same syntax as mustache sections but should not be
-confused with one another. Sections are akin to an implicit `each` or
-`with` statement depending on the input data and helpers are explicit
-pieces of code that are free to implement whatever behavior they like.
-The [mustache spec](http://mustache.github.io/mustache.5.html)
-defines the exact behavior of sections. In the case of name conflicts,
-helpers are given priority.
-
-### Partials
-
-You can register additional templates as partials, which will be used by
-Handlebars when it encounters a partial (`{{> partialName}}`). Partials
-can either be String templates or compiled template functions. Here's an
-example:
-
-```js
-var source = "<ul>{{#people}}<li>{{> link}}</li>{{/people}}</ul>";
-
-Handlebars.registerPartial('link', '<a href="/people/{{id}}">{{name}}</a>')
-var template = Handlebars.compile(source);
-
-var data = { "people": [
-    { "name": "Alan", "id": 1 },
-    { "name": "Yehuda", "id": 2 }
-  ]};
-
-template(data);
-
-// Should render:
-// <ul>
-//   <li><a href="/people/1">Alan</a></li>
-//   <li><a href="/people/2">Yehuda</a></li>
-// </ul>
-```
-
-Partials can also accept parameters
-
-```js
-var source = "<div>{{> roster rosterProperties people=listOfPeople}}</div>";
-
-Handlebars.registerPartial('roster', '<h2>{{rosterName}}</h2>{{#people}}<span>{{id}}: {{name}}</span>{{/people}}')
-var template = Handlebars.compile(source);
-
-var data = {
-	"listOfPeople": [
-		{ "name": "Alan", "id": 1 },
-		{ "name": "Yehuda", "id": 2 }
-	], 
-	"rosterProperties": {
-		"rosterName": "Cool People"
-	}
-};
-
-template(data);
-
-// Should render:
-// <div>
-//  <h2>Cool People</h2>
-//   <span>1: Alan</span>
-//   <span>2: Yehuda</span>
-// </div>
-
-```
-
-### Comments
-
-You can add comments to your templates with the following syntax:
-
-```js
-{{! This is a comment }}
-```
-
-You can also use real html comments if you want them to end up in the output.
-
-```html
-<div>
-    {{! This comment will not end up in the output }}
-    <!-- This comment will show up in the output -->
-</div>
-```
+- [Nested Paths](https://handlebarsjs.com/guide/expressions.html#path-expressions)
+- [Helpers](https://handlebarsjs.com/guide/expressions.html#helpers)
+- [Block Expressions](https://handlebarsjs.com/guide/block-helpers.html#basic-blocks)
+- [Literal Values](https://handlebarsjs.com/guide/expressions.html#literal-segments)
+- [Delimited Comments](https://handlebarsjs.com/guide/#template-comments)

+Block expressions have the same syntax as mustache sections but should not be confused with one another. Sections are akin to an implicit `each` or `with` statement depending on the input data and helpers are explicit pieces of code that are free to implement whatever behavior they like. The [mustache spec](http://mustache.github.io/mustache.5.html) defines the exact behavior of sections. In the case of name conflicts, helpers are given priority.

 ### Compatibility

 There are a few Mustache behaviors that Handlebars does not implement.
 - Handlebars deviates from Mustache slightly in that it does not perform recursive lookup by default. The compile time `compat` flag must be set to enable this functionality. Users should note that there is a performance cost for enabling this flag. The exact cost varies by template, but it's recommended that performance sensitive operations should avoid this mode and instead opt for explicit path references.
- The optional Mustache-style lambdas are not supported. Instead Handlebars provides it's own lambda resolution that follows the behaviors of helpers.
- Alternative delimeters are not supported.
+- The optional Mustache-style lambdas are not supported. Instead Handlebars provides its own lambda resolution that follows the behaviors of helpers.
+- Alternative delimiters are not supported.


-Precompiling Templates
----------------------
-
-Handlebars allows templates to be precompiled and included as javascript
-code rather than the handlebars template allowing for faster startup time.
-
-### Installation
-The precompiler script may be installed via npm using the `npm install -g handlebars`
-command.
-
-### Usage
-
-<pre>
-Precompile handlebar templates.
-Usage: handlebars template...
-
-Options:
-  -a, --amd            Create an AMD format function (allows loading with RequireJS)          [boolean]
-  -f, --output         Output File                                                            [string]
-  -k, --known          Known helpers                                                          [string]
-  -o, --knownOnly      Known helpers only                                                     [boolean]
-  -m, --min            Minimize output                                                        [boolean]
-  -s, --simple         Output template function only.                                         [boolean]
-  -r, --root           Template root. Base value that will be stripped from template names.   [string]
-  -c, --commonjs       Exports CommonJS style, path to Handlebars module                      [string]
-  -h, --handlebarPath  Path to handlebar.js (only valid for amd-style)                        [string]
-  -n, --namespace      Template namespace                                                     [string]
-  -p, --partial        Compiling a partial template                                           [boolean]
-  -d, --data           Include data when compiling                                            [boolean]
-  -e, --extension      Template extension.                                                    [string]
-  -b, --bom            Removes the BOM (Byte Order Mark) from the beginning of the templates. [boolean]
-</pre>
-
-If using the precompiler's normal mode, the resulting templates will be
-stored to the `Handlebars.templates` object using the relative template
-name sans the extension. These templates may be executed in the same
-manner as templates.
-
-If using the simple mode the precompiler will generate a single
-javascript method. To execute this method it must be passed to
-the `Handlebars.template` method and the resulting object may be used as normal.
-
-### Optimizations
-
- Rather than using the full _handlebars.js_ library, implementations that
-  do not need to compile templates at runtime may include _handlebars.runtime.js_
-  whose min+gzip size is approximately 1k.
- If a helper is known to exist in the target environment they may be defined
-  using the `--known name` argument may be used to optimize accesses to these
-  helpers for size and speed.
- When all helpers are known in advance the `--knownOnly` argument may be used
-  to optimize all block helper references.
- Implementations that do not use `@data` variables can improve performance of
-  iteration centric templates by specifying `{data: false}` in the compiler options.
-
 Supported Environments
 ----------------------

@@ -394,6 +122,7 @@ Handlebars in the Wild
 * [Assemble](http://assemble.io), by [@jonschlinkert](https://github.com/jonschlinkert)
  and [@doowb](https://github.com/doowb), is a static site generator that uses Handlebars.js
  as its template engine.
+* [Cory](https://github.com/leo/cory), by [@leo](https://github.com/leo), is another tiny static site generator
 * [CoSchedule](http://coschedule.com) An editorial calendar for WordPress that uses Handlebars.js
 * [dashbars](https://github.com/pismute/dashbars) A modern helper library for Handlebars.js.
 * [Ember.js](http://www.emberjs.com) makes Handlebars.js the primary way to
@@ -414,13 +143,16 @@ Handlebars in the Wild
  Handlebars.js with [jQuery](http://jquery.com/).
 * [Lumbar](http://walmartlabs.github.io/lumbar) provides easy module-based template management for
  handlebars projects.
+* [Marionette.Handlebars](https://github.com/hashchange/marionette.handlebars) adds support for Handlebars and Mustache templates to Marionette.
 * [sammy.js](http://github.com/quirkey/sammy) by Aaron Quint, a.k.a. quirkey,
  supports Handlebars.js as one of its template plugins.
 * [SproutCore](http://www.sproutcore.com) uses Handlebars.js as its main
  templating engine, extending it with automatic data binding support.
 * [YUI](http://yuilibrary.com/yui/docs/handlebars/) implements a port of handlebars
 * [Swag](https://github.com/elving/swag) by [@elving](https://github.com/elving) is a growing collection of helpers for handlebars.js. Give your handlebars.js templates some swag son!
-* [DOMBars](https://github.com/blakeembrey/dombars) is a DOM-based templating engine built on the Handlebars parser and runtime
+* [DOMBars](https://github.com/blakeembrey/dombars) is a DOM-based templating engine built on the Handlebars parser and runtime **DEPRECATED**
+* [promised-handlebars](https://github.com/nknapp/promised-handlebars) is a wrapper for Handlebars that allows helpers to return Promises.
+* [just-handlebars-helpers](https://github.com/leapfrogtechnology/just-handlebars-helpers) A fully tested lightweight package with common Handlebars helpers.

 External Resources
 ------------------
@@ -433,6 +165,4 @@ License
 -------
 Handlebars.js is released under the MIT license.

-[bower-repo]: https://github.com/components/handlebars.js
-[builds-page]: http://builds.handlebarsjs.com.s3.amazonaws.com/bucket-listing.html?sort=lastmod&sortdir=desc
 [pull-request]: https://github.com/wycats/handlebars.js/pull/new/master
@@ -0,0 +1,36 @@
+# Test against these versions of Node.js
+environment:
+  matrix:
+    - nodejs_version: "10"
+
+platform:
+  - x64
+
+# Install scripts (runs after repo cloning)
+install:
+  # Get the latest stable version of Node.js
+  - ps: Install-Product node $env:nodejs_version $env:platform
+  # Clone submodules (mustache spec)
+  - cmd: git submodule update --init --recursive
+  # Install modules
+  - cmd: npm ci
+
+
+# Post-install test scripts
+test_script:
+  # Output useful info for debugging
+  - cmd: node --version
+  - cmd: npm --version
+  # Run tests
+  - cmd: npm run test
+
+# Don't actually build
+build: off
+
+on_failure:
+  - cmd: 7z a coverage.zip coverage
+  - cmd: appveyor PushArtifact coverage.zip
+
+
+# Set build version format here instead of in the admin panel
+version: "{build}"
@@ -0,0 +1,15 @@
+{
+  "extends": "prettier",
+  "globals": {
+    "require": true
+  },
+  "rules": {
+    // Disabling for tests, for now.
+    "no-path-concat": 0,
+
+    "no-var": 0,
+    "no-shadow": 0,
+    "handle-callback-err": 0,
+    "no-console": 0
+  }
+}
@@ -1,13 +1,14 @@
-var _ = require('underscore'),
-    async = require('async'),
-    fs = require('fs'),
-    zlib = require('zlib');
+var async = require('neo-async'),
+  fs = require('fs'),
+  zlib = require('zlib');

 module.exports = function(grunt, callback) {
  var distFiles = fs.readdirSync('dist'),
-      distSizes = {};
+    distSizes = {};

-  async.each(distFiles, function(file, callback) {
+  async.each(
+    distFiles,
+    function(file, callback) {
      var content;
      try {
        content = fs.readFileSync('dist/' + file);
@@ -33,7 +34,10 @@ module.exports = function(grunt, callback) {
      });
    },
    function() {
-      grunt.log.writeln('Distribution sizes: ' + JSON.stringify(distSizes, undefined, 2));
+      grunt.log.writeln(
+        'Distribution sizes: ' + JSON.stringify(distSizes, undefined, 2)
+      );
      callback([distSizes]);
-    });
+    }
+  );
 };
@@ -1,5 +1,5 @@
 var _ = require('underscore'),
-    templates = require('./templates');
+  templates = require('./templates');

 module.exports = function(grunt, callback) {
  // Deferring to here in case we have a build for parser, etc as part of this grunt exec
@@ -8,12 +8,17 @@ module.exports = function(grunt, callback) {
  var templateSizes = {};
  _.each(templates, function(info, template) {
    var src = info.handlebars,
-        compiled = Handlebars.precompile(src, {}),
-        knownHelpers = Handlebars.precompile(src, {knownHelpersOnly: true, knownHelpers: info.helpers});
+      compiled = Handlebars.precompile(src, {}),
+      knownHelpers = Handlebars.precompile(src, {
+        knownHelpersOnly: true,
+        knownHelpers: info.helpers
+      });

    templateSizes[template] = compiled.length;
    templateSizes['knownOnly_' + template] = knownHelpers.length;
  });
-  grunt.log.writeln('Precompiled sizes: ' + JSON.stringify(templateSizes, undefined, 2));
+  grunt.log.writeln(
+    'Precompiled sizes: ' + JSON.stringify(templateSizes, undefined, 2)
+  );
  callback([templateSizes]);
 };
@@ -1,6 +1,6 @@
 module.exports = {
  helpers: {
-    foo: function(options) {
+    foo: function() {
      return '';
    }
  },
@@ -8,5 +8,6 @@ module.exports = {
    bar: true
  },

-  handlebars: '{{foo person "person" 1 true foo=bar foo="person" foo=1 foo=true}}'
+  handlebars:
+    '{{foo person "person" 1 true foo=bar foo="person" foo=1 foo=true}}'
 };
@@ -1,7 +1,14 @@
 module.exports = {
-  context: { names: [{name: "Moe"}, {name: "Larry"}, {name: "Curly"}, {name: "Shemp"}] },
-  handlebars: "{{#each names}}{{name}}{{/each}}",
-  dust: "{#names}{name}{/names}",
-  mustache: "{{#names}}{{name}}{{/names}}",
-  eco: "<% for item in @names: %><%= item.name %><% end %>"
+  context: {
+    names: [
+      { name: 'Moe' },
+      { name: 'Larry' },
+      { name: 'Curly' },
+      { name: 'Shemp' }
+    ]
+  },
+  handlebars: '{{#each names}}{{name}}{{/each}}',
+  dust: '{#names}{name}{/names}',
+  mustache: '{{#names}}{{name}}{{/names}}',
+  eco: '<% for item in @names: %><%= item.name %><% end %>'
 };
@@ -1,4 +1,11 @@
 module.exports = {
-  context: { names: [{name: "Moe"}, {name: "Larry"}, {name: "Curly"}, {name: "Shemp"}] },
-  handlebars: "{{#names}}{{name}}{{/names}}"
-}
+  context: {
+    names: [
+      { name: 'Moe' },
+      { name: 'Larry' },
+      { name: 'Curly' },
+      { name: 'Shemp' }
+    ]
+  },
+  handlebars: '{{#names}}{{name}}{{/names}}'
+};
@@ -3,13 +3,13 @@ var fs = require('fs');
 module.exports = {
  context: {
    header: function() {
-      return "Colors";
+      return 'Colors';
    },
-    hasItems: true,   // To make things fairer in mustache land due to no `{{if}}` construct on arrays
+    hasItems: true, // To make things fairer in mustache land due to no `{{if}}` construct on arrays
    items: [
-      {name: "red", current: true, url: "#Red"},
-      {name: "green", current: false, url: "#Green"},
-      {name: "blue", current: false, url: "#Blue"}
+      { name: 'red', current: true, url: '#Red' },
+      { name: 'green', current: false, url: '#Green' },
+      { name: 'blue', current: false, url: '#Blue' }
    ]
  },

@@ -1,4 +1,11 @@
 module.exports = {
-  context: { names: [{name: "Moe"}, {name: "Larry"}, {name: "Curly"}, {name: "Shemp"}] },
-  handlebars: "{{#each names}}{{@index}}{{name}}{{/each}}"
-}
+  context: {
+    names: [
+      { name: 'Moe' },
+      { name: 'Larry' },
+      { name: 'Curly' },
+      { name: 'Shemp' }
+    ]
+  },
+  handlebars: '{{#each names}}{{@index}}{{name}}{{/each}}'
+};
@@ -1,6 +1,14 @@
 module.exports = {
-  context: { names: [{name: "Moe"}, {name: "Larry"}, {name: "Curly"}, {name: "Shemp"}], foo: 'bar' },
-  handlebars: "{{#each names}}{{../foo}}{{/each}}",
-  mustache: "{{#names}}{{foo}}{{/names}}",
-  eco: "<% for item in @names: %><%= @foo %><% end %>"
+  context: {
+    names: [
+      { name: 'Moe' },
+      { name: 'Larry' },
+      { name: 'Curly' },
+      { name: 'Shemp' }
+    ],
+    foo: 'bar'
+  },
+  handlebars: '{{#each names}}{{../foo}}{{/each}}',
+  mustache: '{{#names}}{{foo}}{{/names}}',
+  eco: '<% for item in @names: %><%= @foo %><% end %>'
 };
@@ -1,6 +1,16 @@
 module.exports = {
-  context: { names: [{bat: 'foo', name: ["Moe"]}, {bat: 'foo', name: ["Larry"]}, {bat: 'foo', name: ["Curly"]}, {bat: 'foo', name: ["Shemp"]}], foo: 'bar' },
-  handlebars: "{{#each names}}{{#each name}}{{../bat}}{{../../foo}}{{/each}}{{/each}}",
-  mustache: "{{#names}}{{#name}}{{bat}}{{foo}}{{/name}}{{/names}}",
-  eco: "<% for item in @names: %><% for child in item.name: %><%= item.bat %><%= @foo %><% end %><% end %>"
+  context: {
+    names: [
+      { bat: 'foo', name: ['Moe'] },
+      { bat: 'foo', name: ['Larry'] },
+      { bat: 'foo', name: ['Curly'] },
+      { bat: 'foo', name: ['Shemp'] }
+    ],
+    foo: 'bar'
+  },
+  handlebars:
+    '{{#each names}}{{#each name}}{{../bat}}{{../../foo}}{{/each}}{{/each}}',
+  mustache: '{{#names}}{{#name}}{{bat}}{{foo}}{{/name}}{{/names}}',
+  eco:
+    '<% for item in @names: %><% for child in item.name: %><%= item.bat %><%= @foo %><% end %><% end %>'
 };
@@ -1,4 +1,4 @@
 module.exports = {
-  context: { person: { name: "Larry", age: 45 } },
-  handlebars: "{{#person}}{{name}}{{age}}{{/person}}"
+  context: { person: { name: 'Larry', age: 45 } },
+  handlebars: '{{#person}}{{name}}{{age}}{{/person}}'
 };
@@ -1,7 +1,7 @@
 module.exports = {
-  context: { person: { name: "Larry", age: 45 } },
-  handlebars: "{{#with person}}{{name}}{{age}}{{/with}}",
-  dust: "{#person}{name}{age}{/person}",
-  eco: "<%= @person.name %><%= @person.age %>",
-  mustache: "{{#person}}{{name}}{{age}}{{/person}}"
+  context: { person: { name: 'Larry', age: 45 } },
+  handlebars: '{{#with person}}{{name}}{{age}}{{/with}}',
+  dust: '{#person}{name}{age}{/person}',
+  eco: '<%= @person.name %><%= @person.age %>',
+  mustache: '{{#person}}{{name}}{{age}}{{/person}}'
 };
@@ -1,10 +1,13 @@
 module.exports = {
-  context: { name: '1', kids: [{ name: '1.1', kids: [{name: '1.1.1', kids: []}] }] },
-  partials: {
-    mustache: { recursion: "{{name}}{{#kids}}{{>recursion}}{{/kids}}" },
-    handlebars: { recursion: "{{name}}{{#each kids}}{{>recursion}}{{/each}}" }
+  context: {
+    name: '1',
+    kids: [{ name: '1.1', kids: [{ name: '1.1.1', kids: [] }] }]
  },
-  handlebars: "{{name}}{{#each kids}}{{>recursion}}{{/each}}",
-  dust: "{name}{#kids}{>recursion:./}{/kids}",
-  mustache: "{{name}}{{#kids}}{{>recursion}}{{/kids}}"
+  partials: {
+    mustache: { recursion: '{{name}}{{#kids}}{{>recursion}}{{/kids}}' },
+    handlebars: { recursion: '{{name}}{{#each kids}}{{>recursion}}{{/each}}' }
+  },
+  handlebars: '{{name}}{{#each kids}}{{>recursion}}{{/each}}',
+  dust: '{name}{#kids}{>recursion:./}{/kids}',
+  mustache: '{{name}}{{#kids}}{{>recursion}}{{/kids}}'
 };
@@ -1,11 +1,19 @@
 module.exports = {
-  context: { peeps: [{name: "Moe", count: 15}, {name: "Larry", count: 5}, {name: "Curly", count: 1}] },
+  context: {
+    peeps: [
+      { name: 'Moe', count: 15 },
+      { name: 'Larry', count: 5 },
+      { name: 'Curly', count: 1 }
+    ]
+  },
  partials: {
-    mustache: { variables: "Hello {{name}}! You have {{count}} new messages." },
-    handlebars: { variables: "Hello {{name}}! You have {{count}} new messages." }
+    mustache: { variables: 'Hello {{name}}! You have {{count}} new messages.' },
+    handlebars: {
+      variables: 'Hello {{name}}! You have {{count}} new messages.'
+    }
  },

-  handlebars: "{{#each peeps}}{{>variables}}{{/each}}",
-  dust: "{#peeps}{>variables/}{/peeps}",
-  mustache: "{{#peeps}}{{>variables}}{{/peeps}}"
+  handlebars: '{{#each peeps}}{{>variables}}{{/each}}',
+  dust: '{#peeps}{>variables/}{/peeps}',
+  mustache: '{{#peeps}}{{>variables}}{{/peeps}}'
 };
@@ -1,7 +1,9 @@
 module.exports = {
-  context: { person: { name: {bar: {baz: "Larry"}}, age: 45 } },
-  handlebars: "{{person.name.bar.baz}}{{person.age}}{{person.foo}}{{animal.age}}",
-  dust: "{person.name.bar.baz}{person.age}{person.foo}{animal.age}",
-  eco: "<%= @person.name.bar.baz %><%= @person.age %><%= @person.foo %><% if @animal: %><%= @animal.age %><% end %>",
-  mustache: "{{person.name.bar.baz}}{{person.age}}{{person.foo}}{{animal.age}}"
+  context: { person: { name: { bar: { baz: 'Larry' } }, age: 45 } },
+  handlebars:
+    '{{person.name.bar.baz}}{{person.age}}{{person.foo}}{{animal.age}}',
+  dust: '{person.name.bar.baz}{person.age}{person.foo}{animal.age}',
+  eco:
+    '<%= @person.name.bar.baz %><%= @person.age %><%= @person.foo %><% if @animal: %><%= @animal.age %><% end %>',
+  mustache: '{{person.name.bar.baz}}{{person.age}}{{person.foo}}{{animal.age}}'
 };
@@ -1,7 +1,7 @@
 module.exports = {
  context: {},
-  handlebars: "Hello world",
-  dust: "Hello world",
-  mustache: "Hello world",
-  eco: "Hello world"
+  handlebars: 'Hello world',
+  dust: 'Hello world',
+  mustache: 'Hello world',
+  eco: 'Hello world'
 };
@@ -4,11 +4,11 @@ module.exports = {
      return 'foo ' + value;
    },
    header: function() {
-      return "Colors";
+      return 'Colors';
    }
  },
-  handlebars: "{{echo (header)}}",
-  eco: "<%= @echo(@header()) %>"
+  handlebars: '{{echo (header)}}',
+  eco: '<%= @echo(@header()) %>'
 };

 module.exports.context = module.exports.helpers;
@@ -1,8 +1,7 @@
 module.exports = {
-  context: {name: "Mick", count: 30},
-  handlebars:  "Hello {{name}}! You have {{count}} new messages.",
-  dust: "Hello {name}! You have {count} new messages.",
-  mustache: "Hello {{name}}! You have {{count}} new messages.",
-  eco: "Hello <%= @name %>! You have <%= @count %> new messages."
+  context: { name: 'Mick', count: 30 },
+  handlebars: 'Hello {{name}}! You have {{count}} new messages.',
+  dust: 'Hello {name}! You have {count} new messages.',
+  mustache: 'Hello {{name}}! You have {{count}} new messages.',
+  eco: 'Hello <%= @name %>! You have <%= @count %> new messages.'
 };
-
@@ -1,52 +1,66 @@
 var _ = require('underscore'),
-    runner = require('./util/template-runner'),
-    templates = require('./templates'),
-
-    eco, dust, Handlebars, Mustache, eco;
+  runner = require('./util/template-runner'),
+  eco,
+  dust,
+  Handlebars,
+  Mustache;

 try {
-  dust = require("dustjs-linkedin");
-} catch (err) { /* NOP */ }
+  dust = require('dustjs-linkedin');
+} catch (err) {
+  /* NOP */
+}

 try {
-  Mustache = require("mustache");
-} catch (err) { /* NOP */ }
+  Mustache = require('mustache');
+} catch (err) {
+  /* NOP */
+}

 try {
-  eco = require("eco");
-} catch (err) { /* NOP */ }
+  eco = require('eco');
+} catch (err) {
+  /* NOP */
+}

 function error() {
-  throw new Error("EWOT");
+  throw new Error('EWOT');
 }

 function makeSuite(bench, name, template, handlebarsOnly) {
  // Create aliases to minimize any impact from having to walk up the closure tree.
  var templateName = name,
+    context = template.context,
+    partials = template.partials,
+    handlebarsOut,
+    compatOut,
+    dustOut,
+    ecoOut,
+    mustacheOut;

-      context = template.context,
-      partials = template.partials,
-
-      handlebarsOut,
-      compatOut,
-      dustOut,
-      ecoOut,
-      mustacheOut;
-
-  var handlebar = Handlebars.compile(template.handlebars, {data: false}),
-      compat =  Handlebars.compile(template.handlebars, {data: false, compat: true}),
-      options = {helpers: template.helpers};
-  _.each(template.partials && template.partials.handlebars, function(partial, name) {
-    Handlebars.registerPartial(name, Handlebars.compile(partial, {data: false}));
+  var handlebar = Handlebars.compile(template.handlebars, { data: false }),
+    compat = Handlebars.compile(template.handlebars, {
+      data: false,
+      compat: true
+    }),
+    options = { helpers: template.helpers };
+  _.each(template.partials && template.partials.handlebars, function(
+    partial,
+    partialName
+  ) {
+    Handlebars.registerPartial(
+      partialName,
+      Handlebars.compile(partial, { data: false })
+    );
  });

  handlebarsOut = handlebar(context, options);
-  bench("handlebars", function() {
+  bench('handlebars', function() {
    handlebar(context, options);
  });

  compatOut = compat(context, options);
-  bench("compat", function() {
+  bench('compat', function() {
    compat(context, options);
  });

@@ -59,10 +73,12 @@ function makeSuite(bench, name, template, handlebarsOnly) {
      dustOut = false;
      dust.loadSource(dust.compile(template.dust, templateName));

-      dust.render(templateName, context, function(err, out) { dustOut = out; });
+      dust.render(templateName, context, function(err, out) {
+        dustOut = out;
+      });

-      bench("dust", function() {
-        dust.render(templateName, context, function(err, out) { });
+      bench('dust', function() {
+        dust.render(templateName, context, function() {});
      });
    } else {
      bench('dust', error);
@@ -75,26 +91,26 @@ function makeSuite(bench, name, template, handlebarsOnly) {

      ecoOut = ecoTemplate(context);

-      bench("eco", function() {
+      bench('eco', function() {
        ecoTemplate(context);
      });
    } else {
-      bench("eco", error);
+      bench('eco', error);
    }
  }

  if (Mustache) {
    var mustacheSource = template.mustache,
-        mustachePartials = partials && partials.mustache;
+      mustachePartials = partials && partials.mustache;

    if (mustacheSource) {
      mustacheOut = Mustache.to_html(mustacheSource, context, mustachePartials);

-      bench("mustache", function() {
+      bench('mustache', function() {
        Mustache.to_html(mustacheSource, context, mustachePartials);
      });
    } else {
-      bench("mustache", error);
+      bench('mustache', error);
    }
  }

@@ -108,9 +124,16 @@ function makeSuite(bench, name, template, handlebarsOnly) {
    b = b.replace(/\s/g, '');

    if (handlebarsOut !== b) {
-      throw new Error('Template output mismatch: ' + name
-            + '\n\nHandlebars: ' + handlebarsOut
-            + '\n\n' + lang + ': ' + b);
+      throw new Error(
+        'Template output mismatch: ' +
+          name +
+          '\n\nHandlebars: ' +
+          handlebarsOut +
+          '\n\n' +
+          lang +
+          ': ' +
+          b
+      );
    }
  }

@@ -1,7 +1,7 @@
 var _ = require('underscore'),
-    Benchmark = require("benchmark");
+  Benchmark = require('benchmark');

-var BenchWarmer = function(names) {
+function BenchWarmer() {
  this.benchmarks = [];
  this.currentBenches = [];
  this.names = [];
@@ -9,9 +9,9 @@ var BenchWarmer = function(names) {
  this.minimum = Infinity;
  this.maximum = -Infinity;
  this.errors = {};
-};
+}

-var print = require("sys").print;
+var print = require('util').print;

 BenchWarmer.prototype = {
  winners: function(benches) {
@@ -29,20 +29,25 @@ BenchWarmer.prototype = {
    });
  },
  push: function(name, fn) {
-    if(this.names.indexOf(name) == -1) {
+    if (this.names.indexOf(name) === -1) {
      this.names.push(name);
    }

-    var first = this.first, suiteName = this.suiteName, self = this;
+    var first = this.first,
+      suiteName = this.suiteName,
+      self = this;
    this.first = false;

    var bench = new Benchmark(fn, {
-      name: this.suiteName + ": " + name,
+      name: this.suiteName + ': ' + name,
      onComplete: function() {
-        if(first) { self.startLine(suiteName); }
+        if (first) {
+          self.startLine(suiteName);
+        }
        self.writeBench(bench);
        self.currentBenches.push(bench);
-      }, onError: function() {
+      },
+      onError: function() {
        self.errors[this.name] = this;
      }
    });
@@ -58,7 +63,7 @@ BenchWarmer.prototype = {
    this.printHeader('ops/msec', true);

    Benchmark.invoke(this.benchmarks, {
-      name: "run",
+      name: 'run',
      onComplete: function() {
        self.scaleTimes();

@@ -75,56 +80,75 @@ BenchWarmer.prototype = {
        });
        print('\n');

-        var errors = false, prop, bench;
-        for(prop in self.errors) {
-          if (self.errors.hasOwnProperty(prop)
-              && self.errors[prop].error.message !== 'EWOT') {
+        var errors = false,
+          prop,
+          bench;
+        for (prop in self.errors) {
+          if (
+            Object.prototype.hasOwnProperty.call(self, prop) &&
+            self.errors[prop].error.message !== 'EWOT'
+          ) {
            errors = true;
            break;
          }
        }

-        if(errors) {
-          print("\n\nErrors:\n");
-          for(prop in self.errors) {
-            if (self.errors.hasOwnProperty(prop)
-                && self.errors[prop].error.message !== 'EWOT') {
+        if (errors) {
+          print('\n\nErrors:\n');
+          Object.keys(self.errors).forEach(function(prop) {
+            if (self.errors[prop].error.message !== 'EWOT') {
              bench = self.errors[prop];
-              print("\n" + bench.name + ":\n");
+              print('\n' + bench.name + ':\n');
              print(bench.error.message);
-              if(bench.error.stack) {
-                print(bench.error.stack.join("\n"));
+              if (bench.error.stack) {
+                print(bench.error.stack.join('\n'));
              }
-              print("\n");
+              print('\n');
            }
-          }
+          });
        }

        callback();
      }
    });

-    print("\n");
+    print('\n');
  },

  scaleTimes: function() {
-    var scaled = this.scaled = {};
-    _.each(this.times, function(times, name) {
-      var output = scaled[name] = {};
+    var scaled = (this.scaled = {});
+    _.each(
+      this.times,
+      function(times, name) {
+        var output = (scaled[name] = {});

-      _.each(times, function(time, lang) {
-        output[lang] = ((time - this.minimum) / (this.maximum - this.minimum) * 100).toFixed(2);
-      }, this);
-    }, this);
+        _.each(
+          times,
+          function(time, lang) {
+            output[lang] = (
+              ((time - this.minimum) / (this.maximum - this.minimum)) *
+              100
+            ).toFixed(2);
+          },
+          this
+        );
+      },
+      this
+    );
  },

  printHeader: function(title, winners) {
-    var benchSize = 0, names = this.names, i, l;
+    var benchSize = 0,
+      names = this.names,
+      i,
+      l;

-    for(i=0, l=names.length; i<l; i++) {
+    for (i = 0, l = names.length; i < l; i++) {
      var name = names[i];

-      if(benchSize < name.length) { benchSize = name.length; }
+      if (benchSize < name.length) {
+        benchSize = name.length;
+      }
    }

    this.nameSize = benchSize + 2;
@@ -133,28 +157,30 @@ BenchWarmer.prototype = {

    this.startLine(title);
    horSize = horSize + this.benchSize;
-    for(i=0, l=names.length; i<l; i++) {
+    for (i = 0, l = names.length; i < l; i++) {
      this.writeValue(names[i]);
      horSize = horSize + this.benchSize;
    }

    if (winners) {
-      print("WINNER(S)");
-      horSize = horSize + "WINNER(S)".length;
+      print('WINNER(S)');
+      horSize = horSize + 'WINNER(S)'.length;
    }

-    print("\n" + new Array(horSize + 1).join("-"));
+    print('\n' + new Array(horSize + 1).join('-'));
  },

  startLine: function(name) {
-    var winners = Benchmark.map(this.winners(this.currentBenches), function(bench) {
-      return bench.name.split(": ")[1];
+    var winners = Benchmark.map(this.winners(this.currentBenches), function(
+      bench
+    ) {
+      return bench.name.split(': ')[1];
    });

    this.currentBenches = [];

-    print(winners.join(", "));
-    print("\n");
+    print(winners.join(', '));
+    print('\n');

    if (name) {
      this.writeValue(name);
@@ -163,35 +189,33 @@ BenchWarmer.prototype = {
  writeBench: function(bench) {
    var out;

-    if(!bench.error) {
+    if (!bench.error) {
      var count = bench.hz,
-          moe   = count * bench.stats.rme / 100,
-          minimum,
-          maximum;
+        moe = (count * bench.stats.rme) / 100,
+        minimum,
+        maximum;

      count = Math.round(count / 1000);
      moe = Math.round(moe / 1000);
      minimum = count - moe;
      maximum = count + moe;

-      out = count + " ±" + moe + " (" + bench.cycles + ")";
+      out = count + ' ±' + moe + ' (' + bench.cycles + ')';

      this.times[bench.suiteName][bench.benchName] = count;
      this.minimum = Math.min(this.minimum, minimum);
      this.maximum = Math.max(this.maximum, maximum);
+    } else if (bench.error.message === 'EWOT') {
+      out = 'NA';
    } else {
-      if (bench.error.message === 'EWOT') {
-        out = 'NA';
-      } else {
-        out = 'E';
-      }
+      out = 'E';
    }
    this.writeValue(out);
  },

  writeValue: function(out) {
    var padding = this.benchSize - out.length + 1;
-    out = out + new Array(padding).join(" ");
+    out = out + new Array(padding).join(' ');
    print(out);
  }
 };
@@ -1,12 +1,12 @@
 var _ = require('underscore'),
-    BenchWarmer = require('./benchwarmer'),
-    templates = require('../templates');
+  BenchWarmer = require('./benchwarmer'),
+  templates = require('../templates');

 module.exports = function(grunt, makeSuite, callback) {
  var warmer = new BenchWarmer();

  var handlebarsOnly = grunt.option('handlebars-only'),
-      grep = grunt.option('grep');
+    grep = grunt.option('grep');
  if (grep) {
    grep = new RegExp(grep);
  }
@@ -22,6 +22,8 @@ module.exports = function(grunt, makeSuite, callback) {
  });

  warmer.bench(function() {
-    callback && callback(warmer.times, warmer.scaled);
+    if (callback) {
+      callback(warmer.times, warmer.scaled);
+    }
  });
 };
@@ -26,7 +26,7 @@ var optimist = require('optimist')
        'type': 'string',
        'description': 'Path to handlebar.js (only valid for amd-style)',
        'alias': 'handlebarPath',
-  	    'default': ''
+        'default': ''
      },
      'k': {
        'type': 'string',
@@ -54,17 +54,27 @@ var optimist = require('optimist')
        'description': 'Output template function only.',
        'alias': 'simple'
      },
+      'N': {
+        'type': 'string',
+        'description': 'Name of passed string templates. Optional if running in a simple mode. Required when operating on multiple templates.',
+        'alias': 'name'
+      },
+      'i': {
+        'type': 'string',
+        'description': 'Generates a template from the passed CLI argument.\n"-" is treated as a special value and causes stdin to be read for the template value.',
+        'alias': 'string'
+      },
      'r': {
        'type': 'string',
        'description': 'Template root. Base value that will be stripped from template names.',
        'alias': 'root'
      },
-      'p' : {
+      'p': {
        'type': 'boolean',
        'description': 'Compiling a partial template',
        'alias': 'partial'
      },
-      'd' : {
+      'd': {
        'type': 'boolean',
        'description': 'Include data when compiling',
        'alias': 'data'
@@ -92,6 +102,7 @@ var optimist = require('optimist')
      }
    })

+    .wrap(120)
    .check(function(argv) {
      if (argv.version) {
        return;
@@ -100,12 +111,18 @@ var optimist = require('optimist')


 var argv = optimist.argv;
-argv.templates = argv._;
+argv.files = argv._;
 delete argv._;

-if (argv.help || (!argv.templates.length && !argv.version)) {
-  optimist.showHelp();
-  return;
-}
+var Precompiler = require('../dist/cjs/precompiler');
+Precompiler.loadTemplates(argv, function(err, opts) {
+  if (err) {
+    throw err;
+  }

-return require('../dist/cjs/precompiler').cli(argv);
+  if (opts.help || (!opts.templates.length && !opts.version)) {
+    optimist.showHelp();
+  } else {
+    Precompiler.cli(opts);
+  }
+});
@@ -1,6 +1,7 @@
 {
  "name": "handlebars",
-  "version": "3.0.3",
+  "version": "4.7.1",
  "main": "handlebars.js",
+  "license": "MIT",
  "dependencies": {}
 }
@@ -2,7 +2,7 @@
 <package>
 	<metadata>
 		<id>handlebars.js</id>
-		<version>3.0.3</version>
+		<version>4.7.1</version>
 		<authors>handlebars.js Authors</authors>
 		<licenseUrl>https://github.com/wycats/handlebars.js/blob/master/LICENSE</licenseUrl>
 		<projectUrl>https://github.com/wycats/handlebars.js/</projectUrl>
@@ -0,0 +1,20 @@
+{
+  "name": "handlebars",
+  "version": "4.7.1",
+  "license": "MIT",
+  "jspm": {
+    "main": "handlebars",
+    "shim": {
+      "handlebars": {
+        "exports": "Handlebars"
+      }
+    },
+    "files": [
+      "handlebars.js",
+      "handlebars.runtime.js"
+    ],
+    "buildConfig": {
+      "minify": true
+    }
+  }
+}
@@ -16,6 +16,34 @@ var ast = Handlebars.parse(myTemplate);
 Handlebars.precompile(ast);
 ```

+### Parsing
+
+There are two primary APIs that are used to parse an existing template into the AST:
+
+#### parseWithoutProcessing
+
+`Handlebars.parseWithoutProcessing` is the primary mechanism to turn a raw template string into the Handlebars AST described in this document. No processing is done on the resulting AST which makes this ideal for codemod (for source to source transformation) tooling.
+
+Example:
+
+```js
+let ast = Handlebars.parseWithoutProcessing(myTemplate);
+```
+
+#### parse
+
+`Handlebars.parse` will parse the template with `parseWithoutProcessing` (see above) then it will update the AST to strip extraneous whitespace. The whitespace stripping functionality handles two distinct situations:
+
+* Removes whitespace around dynamic statements that are on a line by themselves (aka "stand alone")
+* Applies "whitespace control" characters (i.e. `~`) by truncating the `ContentStatement` `value` property appropriately (e.g. `\n\n{{~foo}}` would have a `ContentStatement` with a `value` of `''`)
+
+`Handlebars.parse` is used internally by `Handlebars.precompile` and `Handlebars.compile`.
+
+Example:
+
+```js
+let ast = Handlebars.parse(myTemplate);
+```

 ### Basic

@@ -66,7 +94,7 @@ interface MustacheStatement <: Statement {

 interface BlockStatement <: Statement {
    type: "BlockStatement";
-    path: PathExpression;
+    path: PathExpression | Literal;
    params: [ Expression ];
    hash: Hash;

@@ -83,10 +111,23 @@ interface PartialStatement <: Statement {
    name: PathExpression | SubExpression;
    params: [ Expression ];
    hash: Hash;
-    
+
    indent: string;
    strip: StripFlags | null;
 }
+
+interface PartialBlockStatement <: Statement {
+    type: "PartialBlockStatement";
+    name: PathExpression | SubExpression;
+    params: [ Expression ];
+    hash: Hash;
+
+    program: Program | null;
+
+    indent: string;
+    openStrip: StripFlags | null;
+    closeStrip: StripFlags | null;
+}
 ```

 `name` will be a `SubExpression` when tied to a dynamic partial, i.e. `{{> (foo) }}`, otherwise this is a path or literal whose `original` value is used to lookup the desired partial.
@@ -107,6 +148,33 @@ interface CommentStatement <: Statement {
 }
 ```

+
+```java
+interface Decorator <: Statement {
+    type: "Decorator";
+
+    path: PathExpression | Literal;
+    params: [ Expression ];
+    hash: Hash;
+
+    strip: StripFlags | null;
+}
+
+interface DecoratorBlock <: Statement {
+    type: "DecoratorBlock";
+    path: PathExpression | Literal;
+    params: [ Expression ];
+    hash: Hash;
+
+    program: Program | null;
+
+    openStrip: StripFlags | null;
+    closeStrip: StripFlags | null;
+}
+```
+
+Decorator paths only utilize the `path.original` value and as a consequence do not support depthed evaluation.
+
 ### Expressions

 ```java
@@ -236,7 +304,7 @@ The `Handlebars.JavaScriptCompiler` object has a number of methods that may be c

  - `parent` is the existing code in the path resolution
  - `name` is the current path component
-  - `type` is the type of name being evaluated. May be one of `context`, `data`, `helper`, or `partial`.
+  - `type` is the type of name being evaluated. May be one of `context`, `data`, `helper`, `decorator`, or `partial`.

  Note that this does not impact dynamic partials, which implementors need to be aware of. Overriding `VM.resolvePartial` may be required to support dynamic cases.

@@ -256,21 +324,43 @@ The `Handlebars.JavaScriptCompiler` object has a number of methods that may be c
 - `initializeBuffer()`
    Allows for buffers other than the default string buffer to be used. Generally needs to be paired with a custom `appendToBuffer` implementation.

+### Example for the compiler api.
+
+This example changes all lookups of properties are performed by a helper (`lookupLowerCase`) which looks for `test` if `{{Test}}` occurs in the template. This is just to illustrate how compiler behavior can be change.
+
+There is also [a jsfiddle with this code](https://jsfiddle.net/9D88g/162/) if you want to play around with it.
+
+
 ```javascript
 function MyCompiler() {
  Handlebars.JavaScriptCompiler.apply(this, arguments);
 }
-MyCompiler.prototype = Object.create(Handlebars.JavaScriptCompiler);
+MyCompiler.prototype = new Handlebars.JavaScriptCompiler();

-MyCompiler.nameLookup = function(parent, name, type) {
-  if (type === 'partial') {
-    return 'MyPartialList[' + JSON.stringify(name) ']';
+// Use this compile to compile BlockStatment-Blocks
+MyCompiler.prototype.compiler = MyCompiler
+
+MyCompiler.prototype.nameLookup = function(parent, name, type) {
+  if (type === 'context') {
+    return this.source.functionCall('helpers.lookupLowerCase', '', [parent, JSON.stringify(name)])
  } else {
    return Handlebars.JavaScriptCompiler.prototype.nameLookup.call(this, parent, name, type);
  }
-};
+}

 var env = Handlebars.create();
+env.registerHelper('lookupLowerCase', function(parent, name) {
+  return parent[name.toLowerCase()]
+})
+
 env.JavaScriptCompiler = MyCompiler;
-env.compile('my template');
+
+var template = env.compile('{{#each Test}} ({{Value}}) {{/each}}');
+console.log(template({
+  test: [ 
+    {value: 'a'},
+    {value: 'b'},
+    {value: 'c'}
+    ]
+}));
 ```
@@ -0,0 +1,19 @@
+# Decorators
+
+Decorators allow for blocks to be annotated with metadata or wrapped in functionality prior to execution of the block. This may be used to communicate with the containing helper or to setup a particular state in the system prior to running the block.
+
+Decorators are registered through similar methods as helpers, `registerDecorators` and `unregisterDecorators`. These can then be referenced via the friendly name in the template using the `{{* decorator}}` and `{{#* decorator}}{/decorator}}` syntaxes. These syntaxes are derivatives of the normal mustache syntax and as such have all of the same argument and whitespace behaviors.
+
+Decorators are executed when the block program is instantiated and are passed `(program, props, container, context, data, blockParams, depths)`.
+
+- `program`: The block to wrap
+- `props`: Object used to set metadata on the final function. Any values set on this object will be set on the function, regardless of if the original function is replaced or not. Metadata should be applied using this object as values applied to `program` may be masked by subsequent decorators that may wrap `program`.
+- `container`: The current runtime container
+- `context`: The current context. Since the decorator is run before the block that contains it, this is the parent context.
+- `data`: The current `@data` values
+- `blockParams`: The current block parameters stack
+- `depths`: The current context stack
+
+Decorators may set values on `props` or return a modified function that wraps `program` in particular behaviors. If the decorator returns nothing, then `program` is left unaltered.
+
+The [inline partial](https://github.com/wycats/handlebars.js/blob/master/lib/handlebars/decorators/inline.js) implementation provides an example of decorators being used for both metadata and wrapping behaviors.
@@ -0,0 +1,12 @@
+Add a new integration test by creating a new subfolder
+
+Add a file "test.sh" to that runs the test. "test.sh" should exit with a non-zero exit code 
+and display an error message, if something goes wrong.
+
+* An integration test should reflect real-world setups that use handlebars.
+* It should compile a minimal template and compare the output to an expected output.
+* It should use "../.." as dependency for Handlebars so that the currently built library is used.
+
+Currently, integration tests are only running on Linux, especially in travis-ci.
+
+  
@@ -0,0 +1,13 @@
+module.exports = {
+  extends: ['eslint:recommended', 'plugin:es5/no-es2015', 'prettier'],
+  globals: {
+    self: false
+  },
+  env: {
+    node: true
+  },
+  rules: {
+    'no-console': 'off',
+    'no-var': 'off'
+  }
+};
@@ -0,0 +1,2 @@
+target
+package-lock.json
@@ -0,0 +1,16 @@
+{
+  "name": "multi-nodejs-test",
+  "version": "1.0.0",
+  "description": "Simple integration test with all relevant NodeJS-versions.",
+  "keywords": [],
+  "author": "Nils Knappmeier",
+  "private": true,
+  "license": "MIT",
+  "dependencies": {
+    "handlebars": "file:../.."
+  },
+  "scripts": {
+    "test": "node run-handlebars.js",
+    "test-precompile": "handlebars precompile-test-template.txt.hbs"
+  }
+}
@@ -0,0 +1 @@
+Author: {{author}}
@@ -0,0 +1,11 @@
+// This test should run successfully with node 0.10++ as long as Handlebars has been compiled before
+var assert = require('assert');
+var Handlebars = require('handlebars');
+
+console.log('Testing built Handlebars with Node version ' + process.version);
+
+var template = Handlebars.compile('Author: {{author}}');
+var output = template({ author: 'Yehuda' });
+assert.strictEqual(output, 'Author: Yehuda');
+
+console.log('Success');
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+cd "$( dirname "$( readlink -f "$0" )" )" || exit 1
+# shellcheck disable=SC1090
+[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
+
+# This script tests with precompiler and the built distribution with multiple NodeJS version.
+# The rest of the travis-build will only work with newer NodeJS versions, because the build
+# tools don't support older versions.
+# However, the built distribution should work with older NodeJS versions as well.
+# This test is simple by design. It merely ensures, that calling Handlebars does not fail with old versions.
+# It does (almost) not test for correctness, because that is already done in the mocha-tests.
+# And it does not use any NodeJS based testing framwork to make this part independent of the Node version.
+
+unset npm_config_prefix
+
+echo "Handlebars should be able to run in various versions of NodeJS"
+for i in  0.10 0.12 4 5 6 7 8 9 10 11 ; do
+    rm target node_modules package-lock.json -rf
+    mkdir target
+    nvm install "$i"
+    nvm exec "$i" npm install
+    nvm exec "$i" npm run test || exit 1
+    nvm exec "$i" npm run test-precompile || exit 1
+
+    echo Success
+done
@@ -0,0 +1,13 @@
+#!/bin/bash
+
+cd "$( dirname "$( readlink -f "$0" )" )" || exit 1
+
+for i in */test.sh ; do
+  (
+    echo "----------------------------------------"
+    echo "-- Running integration test: $i"
+    echo "----------------------------------------"
+    cd "$( dirname "$i" )" || exit 1
+    ./test.sh || exit 1
+  )
+done
@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    "@roundingwellos/babel-plugin-handlebars-inline-precompile"
+   // "istanbul"
+  ],
+  "presets": [
+    [
+      "@babel/preset-env"
+    ]
+  ]
+}
@@ -0,0 +1,3 @@
+node_modules
+dist
+package-lock.json
@@ -0,0 +1,24 @@
+{
+  "name": "webpack-babel-test",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "@babel/core": "^7.5.5",
+    "@babel/preset-env": "^7.5.5",
+    "@roundingwellos/babel-plugin-handlebars-inline-precompile": "^3.0.1",
+    "babel-loader": "^8.0.6",
+    "babel-plugin-istanbul": "^5.2.0",
+    "handlebars": "file:../..",
+    "handlebars-loader": "^1.7.1",
+    "nyc": "^14.1.1",
+    "webpack": "^4.39.3",
+    "webpack-cli": "^3.3.7"
+  },
+  "scripts": {
+    "build": "webpack --config webpack.config.js"
+  }
+}
@@ -0,0 +1,12 @@
+import * as Handlebars from 'handlebars/runtime';
+import hbs from 'handlebars-inline-precompile';
+import { assertEquals } from '../../webpack-test/src/lib/assert';
+
+Handlebars.registerHelper('loud', function(text) {
+  return text.toUpperCase();
+});
+
+const template = hbs`{{loud name}}`;
+const output = template({ name: 'yehuda' });
+
+assertEquals(output, 'YEHUDA');
@@ -0,0 +1,5 @@
+export function assertEquals(actual, expected) {
+  if (actual !== expected) {
+    throw new Error(`Expected "${actual}" to equal "${expected}"`);
+  }
+}
@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -e
+
+# Cleanup: package-lock and "npm ci" is not working with local dependencies
+rm dist package-lock.json -rf
+npm install
+npm run build
+
+for i in dist/*-test.js ; do
+  echo "----------------------"
+  echo "-- Running $i"
+  echo "----------------------"
+  node "$i"
+  echo "Success"
+done
@@ -0,0 +1,32 @@
+const fs = require('fs');
+
+const testFiles = fs.readdirSync('src');
+const entryPoints = {};
+testFiles
+  .filter(file => file.match(/-test.js$/))
+  .forEach(file => {
+    entryPoints[file] = `./src/${file}`;
+  });
+
+module.exports = {
+  entry: entryPoints,
+  output: {
+    filename: '[name]',
+    path: __dirname + '/dist'
+  },
+  module: {
+    rules: [
+      {
+        test: /\.js?$/,
+        exclude: /node_modules/,
+        use: {
+          loader: 'babel-loader',
+          options: { cacheDirectory: false }
+        }
+      }
+    ]
+  },
+  optimization: {
+    minimize: false
+  }
+};
@@ -0,0 +1,3 @@
+node_modules
+dist
+package-lock.json
@@ -0,0 +1,21 @@
+{
+  "name": "webpack-test",
+  "description": "Various tests with Handlebars and Webpack",
+  "version": "1.0.0",
+  "main": "index.js",
+  "scripts": {
+    "build": "webpack --config webpack.config.js",
+    "test": "node dist/main.js"
+  },
+  "private": true,
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {},
+  "devDependencies": {
+    "handlebars": "file:../..",
+    "handlebars-loader": "^1.7.1",
+    "webpack": "^4.39.3",
+    "webpack-cli": "^3.3.7"
+  }
+}
@@ -0,0 +1,6 @@
+import Handlebars from 'handlebars/dist/handlebars';
+
+import { assertEquals } from './lib/assert';
+
+const template = Handlebars.compile('Author: {{author}}');
+assertEquals(template({ author: 'Yehuda' }), 'Author: Yehuda');
@@ -0,0 +1,5 @@
+import Handlebars from 'handlebars';
+import { assertEquals } from './lib/assert';
+
+const template = Handlebars.compile('Author: {{author}}');
+assertEquals(template({ author: 'Yehuda' }), 'Author: Yehuda');
@@ -0,0 +1,10 @@
+import { assertEquals } from './lib/assert';
+
+import testTemplate from './test-template.handlebars';
+assertEquals(testTemplate({ author: 'Yehuda' }).trim(), 'Author: Yehuda');
+
+const testTemplateRequire = require('./test-template.handlebars');
+assertEquals(
+  testTemplateRequire({ author: 'Yehuda' }).trim(),
+  'Author: Yehuda'
+);
@@ -0,0 +1,10 @@
+import * as HandlebarsViaImport from 'handlebars';
+const HandlebarsViaRequire = require('handlebars');
+import { assertEquals } from './lib/assert';
+
+HandlebarsViaImport.registerHelper('loud', function(text) {
+  return text.toUpperCase();
+});
+
+const template = HandlebarsViaRequire.compile('Author: {{loud author}}');
+assertEquals(template({ author: 'Yehuda' }), 'Author: YEHUDA');
@@ -0,0 +1,6 @@
+import * as Handlebars from 'handlebars/dist/handlebars';
+
+import { assertEquals } from './lib/assert';
+
+const template = Handlebars.compile('Author: {{author}}');
+assertEquals(template({ author: 'Yehuda' }), 'Author: Yehuda');
@@ -0,0 +1,5 @@
+import * as Handlebars from 'handlebars';
+import { assertEquals } from './lib/assert';
+
+const template = Handlebars.compile('Author: {{author}}');
+assertEquals(template({ author: 'Yehuda' }), 'Author: Yehuda');
@@ -0,0 +1,5 @@
+export function assertEquals(actual, expected) {
+  if (actual !== expected) {
+    throw new Error(`Expected "${actual}" to equal "${expected}"`);
+  }
+}
@@ -0,0 +1,2 @@
+Author: {{author}}
+
@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -e
+
+# Cleanup: package-lock and "npm ci" is not working with local dependencies
+rm dist package-lock.json -rf
+npm install
+npm run build
+
+for i in dist/*-test.js ; do
+  echo "----------------------"
+  echo "-- Running $i"
+  echo "----------------------"
+  node "$i"
+  echo "Success"
+done
@@ -0,0 +1,20 @@
+const fs = require('fs');
+
+const testFiles = fs.readdirSync('src');
+const entryPoints = {};
+testFiles
+  .filter(file => file.match(/-test.js$/))
+  .forEach(file => {
+    entryPoints[file] = `./src/${file}`;
+  });
+
+module.exports = {
+  entry: entryPoints,
+  output: {
+    filename: '[name]',
+    path: __dirname + '/dist'
+  },
+  module: {
+    rules: [{ test: /\.handlebars$/, loader: 'handlebars-loader' }]
+  }
+};
@@ -2,7 +2,11 @@ import runtime from './handlebars.runtime';

 // Compiler imports
 import AST from './handlebars/compiler/ast';
-import { parser as Parser, parse } from './handlebars/compiler/base';
+import {
+  parser as Parser,
+  parse,
+  parseWithoutProcessing
+} from './handlebars/compiler/base';
 import { Compiler, compile, precompile } from './handlebars/compiler/compiler';
 import JavaScriptCompiler from './handlebars/compiler/javascript-compiler';
 import Visitor from './handlebars/compiler/visitor';
@@ -25,6 +29,7 @@ function create() {
  hb.JavaScriptCompiler = JavaScriptCompiler;
  hb.Parser = Parser;
  hb.parse = parse;
+  hb.parseWithoutProcessing = parseWithoutProcessing;

  return hb;
 }
@@ -1,8 +1,13 @@
-import * as Utils from './utils';
+import { createFrame, extend, toString } from './utils';
 import Exception from './exception';
+import { registerDefaultHelpers } from './helpers';
+import { registerDefaultDecorators } from './decorators';
+import logger from './logger';
+import { resetLoggedProperties } from './internal/proto-access';

-export const VERSION = '3.0.1';
-export const COMPILER_REVISION = 6;
+export const VERSION = '4.7.1';
+export const COMPILER_REVISION = 8;
+export const LAST_COMPATIBLE_COMPILER_REVISION = 7;

 export const REVISION_CHANGES = {
  1: '<= 1.0.rc.2', // 1.0.rc.2 is actually rev2 but doesn't report it
@@ -10,31 +15,34 @@ export const REVISION_CHANGES = {
  3: '== 1.0.0-rc.4',
  4: '== 1.x.x',
  5: '== 2.0.0-alpha.x',
-  6: '>= 2.0.0-beta.1'
+  6: '>= 2.0.0-beta.1',
+  7: '>= 4.0.0 <4.3.0',
+  8: '>= 4.3.0'
 };

-const isArray = Utils.isArray,
-      isFunction = Utils.isFunction,
-      toString = Utils.toString,
-      objectType = '[object Object]';
+const objectType = '[object Object]';

-export function HandlebarsEnvironment(helpers, partials) {
+export function HandlebarsEnvironment(helpers, partials, decorators) {
  this.helpers = helpers || {};
  this.partials = partials || {};
+  this.decorators = decorators || {};

  registerDefaultHelpers(this);
+  registerDefaultDecorators(this);
 }

 HandlebarsEnvironment.prototype = {
  constructor: HandlebarsEnvironment,

  logger: logger,
-  log: log,
+  log: logger.log,

  registerHelper: function(name, fn) {
    if (toString.call(name) === objectType) {
-      if (fn) { throw new Exception('Arg not supported with multiple helpers'); }
-      Utils.extend(this.helpers, name);
+      if (fn) {
+        throw new Exception('Arg not supported with multiple helpers');
+      }
+      extend(this.helpers, name);
    } else {
      this.helpers[name] = fn;
    }
@@ -45,200 +53,42 @@ HandlebarsEnvironment.prototype = {

  registerPartial: function(name, partial) {
    if (toString.call(name) === objectType) {
-      Utils.extend(this.partials, name);
+      extend(this.partials, name);
    } else {
      if (typeof partial === 'undefined') {
-        throw new Exception('Attempting to register a partial as undefined');
+        throw new Exception(
+          `Attempting to register a partial called "${name}" as undefined`
+        );
      }
      this.partials[name] = partial;
    }
  },
  unregisterPartial: function(name) {
    delete this.partials[name];
-  }
-};
+  },

-function registerDefaultHelpers(instance) {
-  instance.registerHelper('helperMissing', function(/* [args, ]options */) {
-    if (arguments.length === 1) {
-      // A missing field in a {{foo}} constuct.
-      return undefined;
+  registerDecorator: function(name, fn) {
+    if (toString.call(name) === objectType) {
+      if (fn) {
+        throw new Exception('Arg not supported with multiple decorators');
+      }
+      extend(this.decorators, name);
    } else {
-      // Someone is actually trying to call something, blow up.
-      throw new Exception('Missing helper: "' + arguments[arguments.length - 1].name + '"');
-    }
-  });
-
-  instance.registerHelper('blockHelperMissing', function(context, options) {
-    let inverse = options.inverse,
-        fn = options.fn;
-
-    if (context === true) {
-      return fn(this);
-    } else if (context === false || context == null) {
-      return inverse(this);
-    } else if (isArray(context)) {
-      if (context.length > 0) {
-        if (options.ids) {
-          options.ids = [options.name];
-        }
-
-        return instance.helpers.each(context, options);
-      } else {
-        return inverse(this);
-      }
-    } else {
-      if (options.data && options.ids) {
-        let data = createFrame(options.data);
-        data.contextPath = Utils.appendContextPath(options.data.contextPath, options.name);
-        options = {data: data};
-      }
-
-      return fn(context, options);
-    }
-  });
-
-  instance.registerHelper('each', function(context, options) {
-    if (!options) {
-      throw new Exception('Must pass iterator to #each');
-    }
-
-    let fn = options.fn,
-        inverse = options.inverse,
-        i = 0,
-        ret = '',
-        data,
-        contextPath;
-
-    if (options.data && options.ids) {
-      contextPath = Utils.appendContextPath(options.data.contextPath, options.ids[0]) + '.';
-    }
-
-    if (isFunction(context)) { context = context.call(this); }
-
-    if (options.data) {
-      data = createFrame(options.data);
-    }
-
-    function execIteration(field, index, last) {
-      if (data) {
-        data.key = field;
-        data.index = index;
-        data.first = index === 0;
-        data.last = !!last;
-
-        if (contextPath) {
-          data.contextPath = contextPath + field;
-        }
-      }
-
-      ret = ret + fn(context[field], {
-        data: data,
-        blockParams: Utils.blockParams([context[field], field], [contextPath + field, null])
-      });
-    }
-
-    if (context && typeof context === 'object') {
-      if (isArray(context)) {
-        for (let j = context.length; i < j; i++) {
-          execIteration(i, i, i === context.length - 1);
-        }
-      } else {
-        let priorKey;
-
-        for (let key in context) {
-          if (context.hasOwnProperty(key)) {
-            // We're running the iterations one step out of sync so we can detect
-            // the last iteration without have to scan the object twice and create
-            // an itermediate keys array.
-            if (priorKey) {
-              execIteration(priorKey, i - 1);
-            }
-            priorKey = key;
-            i++;
-          }
-        }
-        if (priorKey) {
-          execIteration(priorKey, i - 1, true);
-        }
-      }
-    }
-
-    if (i === 0) {
-      ret = inverse(this);
-    }
-
-    return ret;
-  });
-
-  instance.registerHelper('if', function(conditional, options) {
-    if (isFunction(conditional)) { conditional = conditional.call(this); }
-
-    // Default behavior is to render the positive path if the value is truthy and not empty.
-    // The `includeZero` option may be set to treat the condtional as purely not empty based on the
-    // behavior of isEmpty. Effectively this determines if 0 is handled by the positive path or negative.
-    if ((!options.hash.includeZero && !conditional) || Utils.isEmpty(conditional)) {
-      return options.inverse(this);
-    } else {
-      return options.fn(this);
-    }
-  });
-
-  instance.registerHelper('unless', function(conditional, options) {
-    return instance.helpers['if'].call(this, conditional, {fn: options.inverse, inverse: options.fn, hash: options.hash});
-  });
-
-  instance.registerHelper('with', function(context, options) {
-    if (isFunction(context)) { context = context.call(this); }
-
-    let fn = options.fn;
-
-    if (!Utils.isEmpty(context)) {
-      if (options.data && options.ids) {
-        let data = createFrame(options.data);
-        data.contextPath = Utils.appendContextPath(options.data.contextPath, options.ids[0]);
-        options = {data: data};
-      }
-
-      return fn(context, options);
-    } else {
-      return options.inverse(this);
-    }
-  });
-
-  instance.registerHelper('log', function(message, options) {
-    let level = options.data && options.data.level != null ? parseInt(options.data.level, 10) : 1;
-    instance.log(level, message);
-  });
-
-  instance.registerHelper('lookup', function(obj, field) {
-    return obj && obj[field];
-  });
-}
-
-export let logger = {
-  methodMap: { 0: 'debug', 1: 'info', 2: 'warn', 3: 'error' },
-
-  // State enum
-  DEBUG: 0,
-  INFO: 1,
-  WARN: 2,
-  ERROR: 3,
-  level: 1,
-
-  // Can be overridden in the host environment
-  log: function(level, message) {
-    if (typeof console !== 'undefined' && logger.level <= level) {
-      let method = logger.methodMap[level];
-      (console[method] || console.log).call(console, message);    // eslint-disable-line no-console
+      this.decorators[name] = fn;
    }
+  },
+  unregisterDecorator: function(name) {
+    delete this.decorators[name];
+  },
+  /**
+   * Reset the memory of illegal property accesses that have already been logged.
+   * @deprecated should only be used in handlebars test-cases
+   */
+  resetLoggedPropertyAccesses() {
+    resetLoggedProperties();
  }
 };

 export let log = logger.log;

-export function createFrame(object) {
-  let frame = Utils.extend({}, object);
-  frame._parent = object;
-  return frame;
-}
+export { createFrame, logger };
@@ -1,152 +1,32 @@
 let AST = {
-  Program: function(statements, blockParams, strip, locInfo) {
-    this.loc = locInfo;
-    this.type = 'Program';
-    this.body = statements;
-
-    this.blockParams = blockParams;
-    this.strip = strip;
-  },
-
-  MustacheStatement: function(path, params, hash, escaped, strip, locInfo) {
-    this.loc = locInfo;
-    this.type = 'MustacheStatement';
-
-    this.path = path;
-    this.params = params || [];
-    this.hash = hash;
-    this.escaped = escaped;
-
-    this.strip = strip;
-  },
-
-  BlockStatement: function(path, params, hash, program, inverse, openStrip, inverseStrip, closeStrip, locInfo) {
-    this.loc = locInfo;
-    this.type = 'BlockStatement';
-
-    this.path = path;
-    this.params = params || [];
-    this.hash = hash;
-    this.program = program;
-    this.inverse = inverse;
-
-    this.openStrip = openStrip;
-    this.inverseStrip = inverseStrip;
-    this.closeStrip = closeStrip;
-  },
-
-  PartialStatement: function(name, params, hash, strip, locInfo) {
-    this.loc = locInfo;
-    this.type = 'PartialStatement';
-
-    this.name = name;
-    this.params = params || [];
-    this.hash = hash;
-
-    this.indent = '';
-    this.strip = strip;
-  },
-
-  ContentStatement: function(string, locInfo) {
-    this.loc = locInfo;
-    this.type = 'ContentStatement';
-    this.original = this.value = string;
-  },
-
-  CommentStatement: function(comment, strip, locInfo) {
-    this.loc = locInfo;
-    this.type = 'CommentStatement';
-    this.value = comment;
-
-    this.strip = strip;
-  },
-
-  SubExpression: function(path, params, hash, locInfo) {
-    this.loc = locInfo;
-
-    this.type = 'SubExpression';
-    this.path = path;
-    this.params = params || [];
-    this.hash = hash;
-  },
-
-  PathExpression: function(data, depth, parts, original, locInfo) {
-    this.loc = locInfo;
-    this.type = 'PathExpression';
-
-    this.data = data;
-    this.original = original;
-    this.parts = parts;
-    this.depth = depth;
-  },
-
-  StringLiteral: function(string, locInfo) {
-    this.loc = locInfo;
-    this.type = 'StringLiteral';
-    this.original =
-      this.value = string;
-  },
-
-  NumberLiteral: function(number, locInfo) {
-    this.loc = locInfo;
-    this.type = 'NumberLiteral';
-    this.original =
-      this.value = Number(number);
-  },
-
-  BooleanLiteral: function(bool, locInfo) {
-    this.loc = locInfo;
-    this.type = 'BooleanLiteral';
-    this.original =
-      this.value = bool === 'true';
-  },
-
-  UndefinedLiteral: function(locInfo) {
-    this.loc = locInfo;
-    this.type = 'UndefinedLiteral';
-    this.original = this.value = undefined;
-  },
-
-  NullLiteral: function(locInfo) {
-    this.loc = locInfo;
-    this.type = 'NullLiteral';
-    this.original = this.value = null;
-  },
-
-  Hash: function(pairs, locInfo) {
-    this.loc = locInfo;
-    this.type = 'Hash';
-    this.pairs = pairs;
-  },
-  HashPair: function(key, value, locInfo) {
-    this.loc = locInfo;
-    this.type = 'HashPair';
-    this.key = key;
-    this.value = value;
-  },
-
  // Public API used to evaluate derived attributes regarding AST nodes
  helpers: {
    // a mustache is definitely a helper if:
    // * it is an eligible helper, and
    // * it has at least one parameter or hash segment
    helperExpression: function(node) {
-      return !!(node.type === 'SubExpression' || node.params.length || node.hash);
+      return (
+        node.type === 'SubExpression' ||
+        ((node.type === 'MustacheStatement' ||
+          node.type === 'BlockStatement') &&
+          !!((node.params && node.params.length) || node.hash))
+      );
    },

    scopedId: function(path) {
-      return (/^\.|this\b/).test(path.original);
+      return /^\.|this\b/.test(path.original);
    },

    // an ID is simple if it only has one part, and that part is not
    // `..` or `this`.
    simpleId: function(path) {
-      return path.parts.length === 1 && !AST.helpers.scopedId(path) && !path.depth;
+      return (
+        path.parts.length === 1 && !AST.helpers.scopedId(path) && !path.depth
+      );
    }
  }
 };

-
 // Must be exported as an object rather than the root of the module as the jison lexer
 // must modify the object to operate properly.
 export default AST;
@@ -1,5 +1,4 @@
 import parser from './parser';
-import AST from './ast';
 import WhitespaceControl from './whitespace-control';
 import * as Helpers from './helpers';
 import { extend } from '../utils';
@@ -7,11 +6,13 @@ import { extend } from '../utils';
 export { parser };

 let yy = {};
-extend(yy, Helpers, AST);
+extend(yy, Helpers);

-export function parse(input, options) {
+export function parseWithoutProcessing(input, options) {
  // Just return if an already-compiled AST was passed in.
-  if (input.type === 'Program') { return input; }
+  if (input.type === 'Program') {
+    return input;
+  }

  parser.yy = yy;

@@ -20,6 +21,14 @@ export function parse(input, options) {
    return new yy.SourceLocation(options && options.srcName, locInfo);
  };

-  let strip = new WhitespaceControl();
-  return strip.accept(parser.parse(input));
+  let ast = parser.parse(input);
+
+  return ast;
+}
+
+export function parse(input, options) {
+  let ast = parseWithoutProcessing(input, options);
+  let strip = new WhitespaceControl(options);
+
+  return strip.accept(ast);
 }
@@ -1,5 +1,5 @@
-/*global define */
-import {isArray} from '../utils';
+/* global define */
+import { isArray } from '../utils';

 let SourceNode;

@@ -38,7 +38,7 @@ if (!SourceNode) {
      this.src = chunks + this.src;
    },
    toStringWithSourceMap: function() {
-      return {code: this.toString()};
+      return { code: this.toString() };
    },
    toString: function() {
      return this.src;
@@ -46,7 +46,6 @@ if (!SourceNode) {
  };
 }

-
 function castChunk(chunk, codeGen, loc) {
  if (isArray(chunk)) {
    let ret = [];
@@ -62,13 +61,15 @@ function castChunk(chunk, codeGen, loc) {
  return chunk;
 }

-
 function CodeGen(srcFile) {
  this.srcFile = srcFile;
  this.source = [];
 }

 CodeGen.prototype = {
+  isEmpty() {
+    return !this.source.length;
+  },
  prepend: function(source, loc) {
    this.source.unshift(this.wrap(source, loc));
  },
@@ -90,17 +91,23 @@ CodeGen.prototype = {
    }
  },

-  empty: function(loc = this.currentLocation || {start: {}}) {
+  empty: function() {
+    let loc = this.currentLocation || { start: {} };
    return new SourceNode(loc.start.line, loc.start.column, this.srcFile);
  },
-  wrap: function(chunk, loc = this.currentLocation || {start: {}}) {
+  wrap: function(chunk, loc = this.currentLocation || { start: {} }) {
    if (chunk instanceof SourceNode) {
      return chunk;
    }

    chunk = castChunk(chunk, this, loc);

-    return new SourceNode(loc.start.line, loc.start.column, this.srcFile, chunk);
+    return new SourceNode(
+      loc.start.line,
+      loc.start.column,
+      this.srcFile,
+      chunk
+    );
  },

  functionCall: function(fn, type, params) {
@@ -109,26 +116,28 @@ CodeGen.prototype = {
  },

  quotedString: function(str) {
-    return '"' + (str + '')
-      .replace(/\\/g, '\\\\')
-      .replace(/"/g, '\\"')
-      .replace(/\n/g, '\\n')
-      .replace(/\r/g, '\\r')
-      .replace(/\u2028/g, '\\u2028')   // Per Ecma-262 7.3 + 7.8.4
-      .replace(/\u2029/g, '\\u2029') + '"';
+    return (
+      '"' +
+      (str + '')
+        .replace(/\\/g, '\\\\')
+        .replace(/"/g, '\\"')
+        .replace(/\n/g, '\\n')
+        .replace(/\r/g, '\\r')
+        .replace(/\u2028/g, '\\u2028') // Per Ecma-262 7.3 + 7.8.4
+        .replace(/\u2029/g, '\\u2029') +
+      '"'
+    );
  },

  objectLiteral: function(obj) {
    let pairs = [];

-    for (let key in obj) {
-      if (obj.hasOwnProperty(key)) {
-        let value = castChunk(obj[key], this);
-        if (value !== 'undefined') {
-          pairs.push([this.quotedString(key), ':', value]);
-        }
+    Object.keys(obj).forEach(key => {
+      let value = castChunk(obj[key], this);
+      if (value !== 'undefined') {
+        pairs.push([this.quotedString(key), ':', value]);
      }
-    }
+    });

    let ret = this.generateList(pairs);
    ret.prepend('{');
@@ -136,23 +145,22 @@ CodeGen.prototype = {
    return ret;
  },

-
-  generateList: function(entries, loc) {
-    let ret = this.empty(loc);
+  generateList: function(entries) {
+    let ret = this.empty();

    for (let i = 0, len = entries.length; i < len; i++) {
      if (i) {
        ret.add(',');
      }

-      ret.add(castChunk(entries[i], this, loc));
+      ret.add(castChunk(entries[i], this));
    }

    return ret;
  },

-  generateArray: function(entries, loc) {
-    let ret = this.generateList(entries, loc);
+  generateArray: function(entries) {
+    let ret = this.generateList(entries);
    ret.prepend('[');
    ret.add(']');

@@ -161,4 +169,3 @@ CodeGen.prototype = {
 };

 export default CodeGen;
-
@@ -1,5 +1,7 @@
+/* eslint-disable new-cap */
+
 import Exception from '../exception';
-import {isArray, indexOf} from '../utils';
+import { isArray, indexOf, extend } from '../utils';
 import AST from './ast';

 const slice = [].slice;
@@ -22,8 +24,11 @@ Compiler.prototype = {

    for (let i = 0; i < len; i++) {
      let opcode = this.opcodes[i],
-          otherOpcode = other.opcodes[i];
-      if (opcode.opcode !== otherOpcode.opcode || !argEquals(opcode.args, otherOpcode.args)) {
+        otherOpcode = other.opcodes[i];
+      if (
+        opcode.opcode !== otherOpcode.opcode ||
+        !argEquals(opcode.args, otherOpcode.args)
+      ) {
        return false;
      }
    }
@@ -52,33 +57,28 @@ Compiler.prototype = {

    options.blockParams = options.blockParams || [];

-    // These changes will propagate to the other compiler components
-    let knownHelpers = options.knownHelpers;
-    options.knownHelpers = {
-      'helperMissing': true,
-      'blockHelperMissing': true,
-      'each': true,
-      'if': true,
-      'unless': true,
-      'with': true,
-      'log': true,
-      'lookup': true
-    };
-    if (knownHelpers) {
-      for (let name in knownHelpers) {
-        if (name in knownHelpers) {
-          options.knownHelpers[name] = knownHelpers[name];
-        }
-      }
-    }
+    options.knownHelpers = extend(
+      Object.create(null),
+      {
+        helperMissing: true,
+        blockHelperMissing: true,
+        each: true,
+        if: true,
+        unless: true,
+        with: true,
+        log: true,
+        lookup: true
+      },
+      options.knownHelpers
+    );

    return this.accept(program);
  },

  compileProgram: function(program) {
    let childCompiler = new this.compiler(), // eslint-disable-line new-cap
-        result = childCompiler.compile(program, this.options),
-        guid = this.guid++;
+      result = childCompiler.compile(program, this.options),
+      guid = this.guid++;

    this.usePartial = this.usePartial || result.usePartial;

@@ -89,6 +89,11 @@ Compiler.prototype = {
  },

  accept: function(node) {
+    /* istanbul ignore next: Sanity code */
+    if (!this[node.type]) {
+      throw new Exception('Unknown type: ' + node.type, node);
+    }
+
    this.sourceNode.unshift(node);
    let ret = this[node.type](node);
    this.sourceNode.shift();
@@ -99,7 +104,7 @@ Compiler.prototype = {
    this.options.blockParams.unshift(program.blockParams);

    let body = program.body,
-        bodyLength = body.length;
+      bodyLength = body.length;
    for (let i = 0; i < bodyLength; i++) {
      this.accept(body[i]);
    }
@@ -116,7 +121,7 @@ Compiler.prototype = {
    transformLiteralToPath(block);

    let program = block.program,
-        inverse = block.inverse;
+      inverse = block.inverse;

    program = program && this.compileProgram(program);
    inverse = inverse && this.compileProgram(inverse);
@@ -148,23 +153,44 @@ Compiler.prototype = {
    this.opcode('append');
  },

+  DecoratorBlock(decorator) {
+    let program = decorator.program && this.compileProgram(decorator.program);
+    let params = this.setupFullMustacheParams(decorator, program, undefined),
+      path = decorator.path;
+
+    this.useDecorators = true;
+    this.opcode('registerDecorator', params.length, path.original);
+  },
+
  PartialStatement: function(partial) {
    this.usePartial = true;

+    let program = partial.program;
+    if (program) {
+      program = this.compileProgram(partial.program);
+    }
+
    let params = partial.params;
    if (params.length > 1) {
-      throw new Exception('Unsupported number of partial arguments: ' + params.length, partial);
+      throw new Exception(
+        'Unsupported number of partial arguments: ' + params.length,
+        partial
+      );
    } else if (!params.length) {
-      params.push({type: 'PathExpression', parts: [], depth: 0});
+      if (this.options.explicitPartialContext) {
+        this.opcode('pushLiteral', 'undefined');
+      } else {
+        params.push({ type: 'PathExpression', parts: [], depth: 0 });
+      }
    }

    let partialName = partial.name.original,
-        isDynamic = partial.name.type === 'SubExpression';
+      isDynamic = partial.name.type === 'SubExpression';
    if (isDynamic) {
      this.accept(partial.name);
    }

-    this.setupFullMustacheParams(partial, undefined, undefined, true);
+    this.setupFullMustacheParams(partial, program, undefined, true);

    let indent = partial.indent || '';
    if (this.options.preventIndent && indent) {
@@ -175,9 +201,12 @@ Compiler.prototype = {
    this.opcode('invokePartial', isDynamic, partialName, indent);
    this.opcode('append');
  },
+  PartialBlockStatement: function(partialBlock) {
+    this.PartialStatement(partialBlock);
+  },

  MustacheStatement: function(mustache) {
-    this.SubExpression(mustache);   // eslint-disable-line new-cap
+    this.SubExpression(mustache);

    if (mustache.escaped && !this.options.noEscape) {
      this.opcode('appendEscaped');
@@ -185,6 +214,9 @@ Compiler.prototype = {
      this.opcode('append');
    }
  },
+  Decorator(decorator) {
+    this.DecoratorBlock(decorator);
+  },

  ContentStatement: function(content) {
    if (content.value) {
@@ -208,38 +240,50 @@ Compiler.prototype = {
  },
  ambiguousSexpr: function(sexpr, program, inverse) {
    let path = sexpr.path,
-        name = path.parts[0],
-        isBlock = program != null || inverse != null;
+      name = path.parts[0],
+      isBlock = program != null || inverse != null;

    this.opcode('getContext', path.depth);

    this.opcode('pushProgram', program);
    this.opcode('pushProgram', inverse);

+    path.strict = true;
    this.accept(path);

    this.opcode('invokeAmbiguous', name, isBlock);
  },

  simpleSexpr: function(sexpr) {
-    this.accept(sexpr.path);
+    let path = sexpr.path;
+    path.strict = true;
+    this.accept(path);
    this.opcode('resolvePossibleLambda');
  },

  helperSexpr: function(sexpr, program, inverse) {
    let params = this.setupFullMustacheParams(sexpr, program, inverse),
-        path = sexpr.path,
-        name = path.parts[0];
+      path = sexpr.path,
+      name = path.parts[0];

    if (this.options.knownHelpers[name]) {
      this.opcode('invokeKnownHelper', params.length, name);
    } else if (this.options.knownHelpersOnly) {
-      throw new Exception('You specified knownHelpersOnly, but used the unknown helper ' + name, sexpr);
+      throw new Exception(
+        'You specified knownHelpersOnly, but used the unknown helper ' + name,
+        sexpr
+      );
    } else {
+      path.strict = true;
      path.falsy = true;

      this.accept(path);
-      this.opcode('invokeHelper', params.length, path.original, AST.helpers.simpleId(path));
+      this.opcode(
+        'invokeHelper',
+        params.length,
+        path.original,
+        AST.helpers.simpleId(path)
+      );
    }
  },

@@ -248,8 +292,8 @@ Compiler.prototype = {
    this.opcode('getContext', path.depth);

    let name = path.parts[0],
-        scoped = AST.helpers.scopedId(path),
-        blockParamId = !path.depth && !scoped && this.blockParamIndex(name);
+      scoped = AST.helpers.scopedId(path),
+      blockParamId = !path.depth && !scoped && this.blockParamIndex(name);

    if (blockParamId) {
      this.opcode('lookupBlockParam', blockParamId, path.parts);
@@ -258,9 +302,15 @@ Compiler.prototype = {
      this.opcode('pushContext');
    } else if (path.data) {
      this.options.data = true;
-      this.opcode('lookupData', path.depth, path.parts);
+      this.opcode('lookupData', path.depth, path.parts, path.strict);
    } else {
-      this.opcode('lookupOnContext', path.parts, path.falsy, scoped);
+      this.opcode(
+        'lookupOnContext',
+        path.parts,
+        path.falsy,
+        path.strict,
+        scoped
+      );
    }
  },

@@ -286,8 +336,8 @@ Compiler.prototype = {

  Hash: function(hash) {
    let pairs = hash.pairs,
-        i = 0,
-        l = pairs.length;
+      i = 0,
+      l = pairs.length;

    this.opcode('pushHash');

@@ -302,7 +352,11 @@ Compiler.prototype = {

  // HELPERS
  opcode: function(name) {
-    this.opcodes.push({ opcode: name, args: slice.call(arguments, 1), loc: this.sourceNode[0].loc });
+    this.opcodes.push({
+      opcode: name,
+      args: slice.call(arguments, 1),
+      loc: this.sourceNode[0].loc
+    });
  },

  addDepth: function(depth) {
@@ -331,8 +385,7 @@ Compiler.prototype = {
    // An eligible helper is one that does not have a complex path, i.e. `this.foo`, `../foo` etc.
    if (isEligible && !isHelper) {
      let name = sexpr.path.parts[0],
-          options = this.options;
-
+        options = this.options;
      if (options.knownHelpers[name]) {
        isHelper = true;
      } else if (options.knownHelpersOnly) {
@@ -360,9 +413,7 @@ Compiler.prototype = {

    if (this.stringParams) {
      if (value.replace) {
-        value = value
-            .replace(/^(\.?\.\/)*/g, '')
-            .replace(/\//g, '.');
+        value = value.replace(/^(\.?\.\/)*/g, '').replace(/\//g, '.');
      }

      if (val.depth) {
@@ -380,7 +431,7 @@ Compiler.prototype = {
      if (this.trackIds) {
        let blockParamIndex;
        if (val.parts && !AST.helpers.scopedId(val) && !val.depth) {
-           blockParamIndex = this.blockParamIndex(val.parts[0]);
+          blockParamIndex = this.blockParamIndex(val.parts[0]);
        }
        if (blockParamIndex) {
          let blockParamChild = val.parts.slice(1).join('.');
@@ -389,8 +440,9 @@ Compiler.prototype = {
          value = val.original || value;
          if (value.replace) {
            value = value
-                .replace(/^\.\//g, '')
-                .replace(/^\.$/g, '');
+              .replace(/^this(?:\.|$)/, '')
+              .replace(/^\.\//, '')
+              .replace(/^\.$/, '');
          }

          this.opcode('pushId', val.type, value);
@@ -417,9 +469,13 @@ Compiler.prototype = {
  },

  blockParamIndex: function(name) {
-    for (let depth = 0, len = this.options.blockParams.length; depth < len; depth++) {
+    for (
+      let depth = 0, len = this.options.blockParams.length;
+      depth < len;
+      depth++
+    ) {
      let blockParams = this.options.blockParams[depth],
-          param = blockParams && indexOf(blockParams, name);
+        param = blockParams && indexOf(blockParams, name);
      if (blockParams && param >= 0) {
        return [depth, param];
      }
@@ -428,8 +484,14 @@ Compiler.prototype = {
 };

 export function precompile(input, options, env) {
-  if (input == null || (typeof input !== 'string' && input.type !== 'Program')) {
-    throw new Exception('You must pass a string or Handlebars AST to Handlebars.precompile. You passed ' + input);
+  if (
+    input == null ||
+    (typeof input !== 'string' && input.type !== 'Program')
+  ) {
+    throw new Exception(
+      'You must pass a string or Handlebars AST to Handlebars.precompile. You passed ' +
+        input
+    );
  }

  options = options || {};
@@ -441,15 +503,22 @@ export function precompile(input, options, env) {
  }

  let ast = env.parse(input, options),
-      environment = new env.Compiler().compile(ast, options);
+    environment = new env.Compiler().compile(ast, options);
  return new env.JavaScriptCompiler().compile(environment, options);
 }

 export function compile(input, options = {}, env) {
-  if (input == null || (typeof input !== 'string' && input.type !== 'Program')) {
-    throw new Exception('You must pass a string or Handlebars AST to Handlebars.compile. You passed ' + input);
+  if (
+    input == null ||
+    (typeof input !== 'string' && input.type !== 'Program')
+  ) {
+    throw new Exception(
+      'You must pass a string or Handlebars AST to Handlebars.compile. You passed ' +
+        input
+    );
  }

+  options = extend({}, options);
  if (!('data' in options)) {
    options.data = true;
  }
@@ -461,8 +530,13 @@ export function compile(input, options = {}, env) {

  function compileInput() {
    let ast = env.parse(input, options),
-        environment = new env.Compiler().compile(ast, options),
-        templateSpec = new env.JavaScriptCompiler().compile(environment, options, undefined, true);
+      environment = new env.Compiler().compile(ast, options),
+      templateSpec = new env.JavaScriptCompiler().compile(
+        environment,
+        options,
+        undefined,
+        true
+      );
    return env.template(templateSpec);
  }

@@ -508,6 +582,13 @@ function transformLiteralToPath(sexpr) {
    let literal = sexpr.path;
    // Casting to string here to make false and 0 literal values play nicely with the rest
    // of the system.
-    sexpr.path = new AST.PathExpression(false, 0, [literal.original + ''], literal.original + '', literal.loc);
+    sexpr.path = {
+      type: 'PathExpression',
+      data: false,
+      depth: 0,
+      parts: [literal.original + ''],
+      original: literal.original + '',
+      loc: literal.loc
+    };
  }
 }
@@ -1,5 +1,18 @@
 import Exception from '../exception';

+function validateClose(open, close) {
+  close = close.path ? close.path.original : close;
+
+  if (open.path.original !== close) {
+    let errorNode = { loc: open.path.loc };
+
+    throw new Exception(
+      open.path.original + " doesn't match " + close,
+      errorNode
+    );
+  }
+}
+
 export function SourceLocation(source, locInfo) {
  this.source = source;
  this.start = {
@@ -14,7 +27,7 @@ export function SourceLocation(source, locInfo) {

 export function id(token) {
  if (/^\[.*\]$/.test(token)) {
-    return token.substr(1, token.length - 2);
+    return token.substring(1, token.length - 1);
  } else {
    return token;
  }
@@ -28,79 +41,111 @@ export function stripFlags(open, close) {
 }

 export function stripComment(comment) {
-  return comment.replace(/^\{\{~?\!-?-?/, '')
-                .replace(/-?-?~?\}\}$/, '');
+  return comment.replace(/^\{\{~?!-?-?/, '').replace(/-?-?~?\}\}$/, '');
 }

-export function preparePath(data, parts, locInfo) {
-  locInfo = this.locInfo(locInfo);
+export function preparePath(data, parts, loc) {
+  loc = this.locInfo(loc);

  let original = data ? '@' : '',
-      dig = [],
-      depth = 0,
-      depthString = '';
+    dig = [],
+    depth = 0;

  for (let i = 0, l = parts.length; i < l; i++) {
    let part = parts[i].part,
-        // If we have [] syntax then we do not treat path references as operators,
-        // i.e. foo.[this] resolves to approximately context.foo['this']
-        isLiteral = parts[i].original !== part;
+      // If we have [] syntax then we do not treat path references as operators,
+      // i.e. foo.[this] resolves to approximately context.foo['this']
+      isLiteral = parts[i].original !== part;
    original += (parts[i].separator || '') + part;

    if (!isLiteral && (part === '..' || part === '.' || part === 'this')) {
      if (dig.length > 0) {
-        throw new Exception('Invalid path: ' + original, {loc: locInfo});
+        throw new Exception('Invalid path: ' + original, { loc });
      } else if (part === '..') {
        depth++;
-        depthString += '../';
      }
    } else {
      dig.push(part);
    }
  }

-  return new this.PathExpression(data, depth, dig, original, locInfo);
+  return {
+    type: 'PathExpression',
+    data,
+    depth,
+    parts: dig,
+    original,
+    loc
+  };
 }

 export function prepareMustache(path, params, hash, open, strip, locInfo) {
  // Must use charAt to support IE pre-10
  let escapeFlag = open.charAt(3) || open.charAt(2),
-      escaped = escapeFlag !== '{' && escapeFlag !== '&';
+    escaped = escapeFlag !== '{' && escapeFlag !== '&';

-  return new this.MustacheStatement(path, params, hash, escaped, strip, this.locInfo(locInfo));
+  let decorator = /\*/.test(open);
+  return {
+    type: decorator ? 'Decorator' : 'MustacheStatement',
+    path,
+    params,
+    hash,
+    escaped,
+    strip,
+    loc: this.locInfo(locInfo)
+  };
 }

-export function prepareRawBlock(openRawBlock, content, close, locInfo) {
-  if (openRawBlock.path.original !== close) {
-    let errorNode = {loc: openRawBlock.path.loc};
-
-    throw new Exception(openRawBlock.path.original + " doesn't match " + close, errorNode);
-  }
+export function prepareRawBlock(openRawBlock, contents, close, locInfo) {
+  validateClose(openRawBlock, close);

  locInfo = this.locInfo(locInfo);
-  let program = new this.Program([content], null, {}, locInfo);
+  let program = {
+    type: 'Program',
+    body: contents,
+    strip: {},
+    loc: locInfo
+  };

-  return new this.BlockStatement(
-      openRawBlock.path, openRawBlock.params, openRawBlock.hash,
-      program, undefined,
-      {}, {}, {},
-      locInfo);
+  return {
+    type: 'BlockStatement',
+    path: openRawBlock.path,
+    params: openRawBlock.params,
+    hash: openRawBlock.hash,
+    program,
+    openStrip: {},
+    inverseStrip: {},
+    closeStrip: {},
+    loc: locInfo
+  };
 }

-export function prepareBlock(openBlock, program, inverseAndProgram, close, inverted, locInfo) {
-  // When we are chaining inverse calls, we will not have a close path
-  if (close && close.path && openBlock.path.original !== close.path.original) {
-    let errorNode = {loc: openBlock.path.loc};
-
-    throw new Exception(openBlock.path.original + ' doesn\'t match ' + close.path.original, errorNode);
+export function prepareBlock(
+  openBlock,
+  program,
+  inverseAndProgram,
+  close,
+  inverted,
+  locInfo
+) {
+  if (close && close.path) {
+    validateClose(openBlock, close);
  }

+  let decorator = /\*/.test(openBlock.open);
+
  program.blockParams = openBlock.blockParams;

-  let inverse,
-      inverseStrip;
+  let inverse, inverseStrip;

  if (inverseAndProgram) {
+    if (decorator) {
+      throw new Exception(
+        'Unexpected inverse block on decorator',
+        inverseAndProgram
+      );
+    }
+
    if (inverseAndProgram.chain) {
      inverseAndProgram.program.body[0].closeStrip = close.strip;
    }
@@ -115,9 +160,60 @@ export function prepareBlock(openBlock, program, inverseAndProgram, close, inver
    program = inverted;
  }

-  return new this.BlockStatement(
-      openBlock.path, openBlock.params, openBlock.hash,
-      program, inverse,
-      openBlock.strip, inverseStrip, close && close.strip,
-      this.locInfo(locInfo));
+  return {
+    type: decorator ? 'DecoratorBlock' : 'BlockStatement',
+    path: openBlock.path,
+    params: openBlock.params,
+    hash: openBlock.hash,
+    program,
+    inverse,
+    openStrip: openBlock.strip,
+    inverseStrip,
+    closeStrip: close && close.strip,
+    loc: this.locInfo(locInfo)
+  };
+}
+
+export function prepareProgram(statements, loc) {
+  if (!loc && statements.length) {
+    const firstLoc = statements[0].loc,
+      lastLoc = statements[statements.length - 1].loc;
+
+    /* istanbul ignore else */
+    if (firstLoc && lastLoc) {
+      loc = {
+        source: firstLoc.source,
+        start: {
+          line: firstLoc.start.line,
+          column: firstLoc.start.column
+        },
+        end: {
+          line: lastLoc.end.line,
+          column: lastLoc.end.column
+        }
+      };
+    }
+  }
+
+  return {
+    type: 'Program',
+    body: statements,
+    strip: {},
+    loc: loc
+  };
+}
+
+export function preparePartialBlock(open, program, close, locInfo) {
+  validateClose(open, close);
+
+  return {
+    type: 'PartialBlockStatement',
+    name: open.path,
+    params: open.params,
+    hash: open.hash,
+    program,
+    openStrip: open.strip,
+    closeStrip: close && close.strip,
+    loc: this.locInfo(locInfo)
+  };
 }
@@ -1,6 +1,6 @@
 import { COMPILER_REVISION, REVISION_CHANGES } from '../base';
 import Exception from '../exception';
-import {isArray} from '../utils';
+import { isArray } from '../utils';
 import CodeGen from './code-gen';

 function Literal(value) {
@@ -12,20 +12,16 @@ function JavaScriptCompiler() {}
 JavaScriptCompiler.prototype = {
  // PUBLIC API: You can override these methods in a subclass to provide
  // alternative compiled forms for name lookup and buffering semantics
-  nameLookup: function(parent, name /* , type*/) {
-    if (JavaScriptCompiler.isValidJavaScriptVariableName(name)) {
-      return [parent, '.', name];
-    } else {
-      return [parent, "['", name, "']"];
-    }
+  nameLookup: function(parent, name /*,  type */) {
+    return this.internalNameLookup(parent, name);
  },
  depthedLookup: function(name) {
-    return [this.aliasable('this.lookup'), '(depths, "', name, '")'];
+    return [this.aliasable('container.lookup'), '(depths, "', name, '")'];
  },

  compilerInfo: function() {
    const revision = COMPILER_REVISION,
-          versions = REVISION_CHANGES[revision];
+      versions = REVISION_CHANGES[revision];
    return [revision, versions];
  },

@@ -53,6 +49,12 @@ JavaScriptCompiler.prototype = {
    return this.quotedString('');
  },
  // END PUBLIC API
+  internalNameLookup: function(parent, name) {
+    this.lookupPropertyFunctionIsUsed = true;
+    return ['lookupProperty(', parent, ',', JSON.stringify(name), ')'];
+  },
+
+  lookupPropertyFunctionIsUsed: false,

  compile: function(environment, options, context, asObject) {
    this.environment = environment;
@@ -64,6 +66,7 @@ JavaScriptCompiler.prototype = {
    this.name = this.environment.name;
    this.isChild = !!context;
    this.context = context || {
+      decorators: [],
      programs: [],
      environments: []
    };
@@ -81,14 +84,18 @@ JavaScriptCompiler.prototype = {

    this.compileChildren(environment, options);

-    this.useDepths = this.useDepths || environment.useDepths || this.options.compat;
+    this.useDepths =
+      this.useDepths ||
+      environment.useDepths ||
+      environment.useDecorators ||
+      this.options.compat;
    this.useBlockParams = this.useBlockParams || environment.useBlockParams;

    let opcodes = environment.opcodes,
-        opcode,
-        firstLoc,
-        i,
-        l;
+      opcode,
+      firstLoc,
+      i,
+      l;

    for (i = 0, l = opcodes.length; i < l; i++) {
      opcode = opcodes[i];
@@ -107,16 +114,58 @@ JavaScriptCompiler.prototype = {
      throw new Exception('Compile completed with content left on stack');
    }

+    if (!this.decorators.isEmpty()) {
+      this.useDecorators = true;
+
+      this.decorators.prepend([
+        'var decorators = container.decorators, ',
+        this.lookupPropertyFunctionVarDeclaration(),
+        ';\n'
+      ]);
+      this.decorators.push('return fn;');
+
+      if (asObject) {
+        this.decorators = Function.apply(this, [
+          'fn',
+          'props',
+          'container',
+          'depth0',
+          'data',
+          'blockParams',
+          'depths',
+          this.decorators.merge()
+        ]);
+      } else {
+        this.decorators.prepend(
+          'function(fn, props, container, depth0, data, blockParams, depths) {\n'
+        );
+        this.decorators.push('}\n');
+        this.decorators = this.decorators.merge();
+      }
+    } else {
+      this.decorators = undefined;
+    }
+
    let fn = this.createFunctionContext(asObject);
    if (!this.isChild) {
      let ret = {
        compiler: this.compilerInfo(),
        main: fn
      };
-      let programs = this.context.programs;
+
+      if (this.decorators) {
+        ret.main_d = this.decorators; // eslint-disable-line camelcase
+        ret.useDecorators = true;
+      }
+
+      let { programs, decorators } = this.context;
      for (i = 0, l = programs.length; i < l; i++) {
        if (programs[i]) {
          ret[i] = programs[i];
+          if (decorators[i]) {
+            ret[i + '_d'] = decorators[i];
+            ret.useDecorators = true;
+          }
        }
      }

@@ -139,11 +188,11 @@ JavaScriptCompiler.prototype = {
      if (!asObject) {
        ret.compiler = JSON.stringify(ret.compiler);

-        this.source.currentLocation = {start: {line: 1, column: 0}};
+        this.source.currentLocation = { start: { line: 1, column: 0 } };
        ret = this.objectLiteral(ret);

        if (options.srcName) {
-          ret = ret.toStringWithSourceMap({file: options.destName});
+          ret = ret.toStringWithSourceMap({ file: options.destName });
          ret.map = ret.map && ret.map.toString();
        } else {
          ret = ret.toString();
@@ -163,6 +212,7 @@ JavaScriptCompiler.prototype = {
    // getContext opcode when it would be a noop
    this.lastContext = 0;
    this.source = new CodeGen(this.options.srcName);
+    this.decorators = new CodeGen(this.options.srcName);
  },

  createFunctionContext: function(asObject) {
@@ -180,16 +230,19 @@ JavaScriptCompiler.prototype = {
    // aliases will not be used, but this case is already being run on the client and
    // we aren't concern about minimizing the template size.
    let aliasCount = 0;
-    for (let alias in this.aliases) {    // eslint-disable-line guard-for-in
+    Object.keys(this.aliases).forEach(alias => {
      let node = this.aliases[alias];
-
-      if (this.aliases.hasOwnProperty(alias) && node.children && node.referenceCount > 1) {
-        varDeclarations += ', alias' + (++aliasCount) + '=' + alias;
+      if (node.children && node.referenceCount > 1) {
+        varDeclarations += ', alias' + ++aliasCount + '=' + alias;
        node.children[0] = 'alias' + aliasCount;
      }
+    });
+
+    if (this.lookupPropertyFunctionIsUsed) {
+      varDeclarations += ', ' + this.lookupPropertyFunctionVarDeclaration();
    }

-    let params = ['depth0', 'helpers', 'partials', 'data'];
+    let params = ['container', 'depth0', 'helpers', 'partials', 'data'];

    if (this.useBlockParams || this.useDepths) {
      params.push('blockParams');
@@ -206,18 +259,23 @@ JavaScriptCompiler.prototype = {

      return Function.apply(this, params);
    } else {
-      return this.source.wrap(['function(', params.join(','), ') {\n  ', source, '}']);
+      return this.source.wrap([
+        'function(',
+        params.join(','),
+        ') {\n  ',
+        source,
+        '}'
+      ]);
    }
  },
  mergeSource: function(varDeclarations) {
    let isSimple = this.environment.isSimple,
-        appendOnly = !this.forceBuffer,
-        appendFirst,
-
-        sourceSeen,
-        bufferStart,
-        bufferEnd;
-    this.source.each((line) => {
+      appendOnly = !this.forceBuffer,
+      appendFirst,
+      sourceSeen,
+      bufferStart,
+      bufferEnd;
+    this.source.each(line => {
      if (line.appendToBuffer) {
        if (bufferStart) {
          line.prepend('  + ');
@@ -243,7 +301,6 @@ JavaScriptCompiler.prototype = {
      }
    });

-
    if (appendOnly) {
      if (bufferStart) {
        bufferStart.prepend('return ');
@@ -252,7 +309,8 @@ JavaScriptCompiler.prototype = {
        this.source.push('return "";');
      }
    } else {
-      varDeclarations += ', buffer = ' + (appendFirst ? '' : this.initializeBuffer());
+      varDeclarations +=
+        ', buffer = ' + (appendFirst ? '' : this.initializeBuffer());

      if (bufferStart) {
        bufferStart.prepend('return buffer + ');
@@ -263,12 +321,25 @@ JavaScriptCompiler.prototype = {
    }

    if (varDeclarations) {
-      this.source.prepend('var ' + varDeclarations.substring(2) + (appendFirst ? '' : ';\n'));
+      this.source.prepend(
+        'var ' + varDeclarations.substring(2) + (appendFirst ? '' : ';\n')
+      );
    }

    return this.source.merge();
  },

+  lookupPropertyFunctionVarDeclaration: function() {
+    return `
+      lookupProperty = container.lookupProperty || function(parent, propertyName) {
+        if (Object.prototype.hasOwnProperty.call(parent, propertyName)) {
+          return parent[propertyName];
+        }
+        return undefined
+    }
+    `.trim();
+  },
+
  // [blockValue]
  //
  // On stack, before: hash, inverse, program, value
@@ -279,8 +350,10 @@ JavaScriptCompiler.prototype = {
  // replace it on the stack with the result of properly
  // invoking blockHelperMissing.
  blockValue: function(name) {
-    let blockHelperMissing = this.aliasable('helpers.blockHelperMissing'),
-        params = [this.contextName(0)];
+    let blockHelperMissing = this.aliasable(
+        'container.hooks.blockHelperMissing'
+      ),
+      params = [this.contextName(0)];
    this.setupHelperArgs(name, 0, params);

    let blockName = this.popStack();
@@ -297,8 +370,10 @@ JavaScriptCompiler.prototype = {
  // On stack, after, if lastHelper: value
  ambiguousBlockValue: function() {
    // We're being a bit cheeky and reusing the options value from the prior exec
-    let blockHelperMissing = this.aliasable('helpers.blockHelperMissing'),
-        params = [this.contextName(0)];
+    let blockHelperMissing = this.aliasable(
+        'container.hooks.blockHelperMissing'
+      ),
+      params = [this.contextName(0)];
    this.setupHelperArgs('', 0, params, true);

    this.flushInline();
@@ -307,9 +382,14 @@ JavaScriptCompiler.prototype = {
    params.splice(1, 0, current);

    this.pushSource([
-        'if (!', this.lastHelper, ') { ',
-          current, ' = ', this.source.functionCall(blockHelperMissing, 'call', params),
-        '}']);
+      'if (!',
+      this.lastHelper,
+      ') { ',
+      current,
+      ' = ',
+      this.source.functionCall(blockHelperMissing, 'call', params),
+      '}'
+    ]);
  },

  // [appendContent]
@@ -339,14 +419,24 @@ JavaScriptCompiler.prototype = {
  // Otherwise, the empty string is appended
  append: function() {
    if (this.isInline()) {
-      this.replaceStack((current) => [' != null ? ', current, ' : ""']);
+      this.replaceStack(current => [' != null ? ', current, ' : ""']);

      this.pushSource(this.appendToBuffer(this.popStack()));
    } else {
      let local = this.popStack();
-      this.pushSource(['if (', local, ' != null) { ', this.appendToBuffer(local, undefined, true), ' }']);
+      this.pushSource([
+        'if (',
+        local,
+        ' != null) { ',
+        this.appendToBuffer(local, undefined, true),
+        ' }'
+      ]);
      if (this.environment.isSimple) {
-        this.pushSource(['else { ', this.appendToBuffer("''", undefined, true), ' }']);
+        this.pushSource([
+          'else { ',
+          this.appendToBuffer("''", undefined, true),
+          ' }'
+        ]);
      }
    }
  },
@@ -358,8 +448,14 @@ JavaScriptCompiler.prototype = {
  //
  // Escape `value` and append it to the buffer
  appendEscaped: function() {
-    this.pushSource(this.appendToBuffer(
-        [this.aliasable('this.escapeExpression'), '(', this.popStack(), ')']));
+    this.pushSource(
+      this.appendToBuffer([
+        this.aliasable('container.escapeExpression'),
+        '(',
+        this.popStack(),
+        ')'
+      ])
+    );
  },

  // [getContext]
@@ -390,7 +486,7 @@ JavaScriptCompiler.prototype = {
  //
  // Looks up the value of `name` on the current context and pushes
  // it onto the stack.
-  lookupOnContext: function(parts, falsy, scoped) {
+  lookupOnContext: function(parts, falsy, strict, scoped) {
    let i = 0;

    if (!scoped && this.options.compat && !this.lastContext) {
@@ -401,7 +497,7 @@ JavaScriptCompiler.prototype = {
      this.pushContext();
    }

-    this.resolvePath('context', parts, i, falsy);
+    this.resolvePath('context', parts, i, falsy, strict);
  },

  // [lookupBlockParam]
@@ -424,26 +520,26 @@ JavaScriptCompiler.prototype = {
  // On stack, after: data, ...
  //
  // Push the data lookup operator
-  lookupData: function(depth, parts) {
+  lookupData: function(depth, parts, strict) {
    if (!depth) {
      this.pushStackLiteral('data');
    } else {
-      this.pushStackLiteral('this.data(data, ' + depth + ')');
+      this.pushStackLiteral('container.data(data, ' + depth + ')');
    }

-    this.resolvePath('data', parts, 0, true);
+    this.resolvePath('data', parts, 0, true, strict);
  },

-  resolvePath: function(type, parts, i, falsy) {
+  resolvePath: function(type, parts, i, falsy, strict) {
    if (this.options.strict || this.options.assumeObjects) {
-      this.push(strictLookup(this.options.strict, this, parts, type));
+      this.push(strictLookup(this.options.strict && strict, this, parts, type));
      return;
    }

    let len = parts.length;
    for (; i < len; i++) {
-      /*eslint-disable no-loop-func */
-      this.replaceStack((current) => {
+      /* eslint-disable no-loop-func */
+      this.replaceStack(current => {
        let lookup = this.nameLookup(current, parts[i], type);
        // We want to ensure that zero and false are handled properly if the context (falsy flag)
        // needs to have the special handling for these values.
@@ -454,7 +550,7 @@ JavaScriptCompiler.prototype = {
          return [' && ', lookup];
        }
      });
-      /*eslint-enable no-loop-func */
+      /* eslint-enable no-loop-func */
    }
  },

@@ -466,7 +562,14 @@ JavaScriptCompiler.prototype = {
  // If the `value` is a lambda, replace it on the stack by
  // the return value of the lambda
  resolvePossibleLambda: function() {
-    this.push([this.aliasable('this.lambda'), '(', this.popStack(), ', ', this.contextName(0), ')']);
+    this.push([
+      this.aliasable('container.lambda'),
+      '(',
+      this.popStack(),
+      ', ',
+      this.contextName(0),
+      ')'
+    ]);
  },

  // [pushStringParam]
@@ -506,7 +609,7 @@ JavaScriptCompiler.prototype = {
    if (this.hash) {
      this.hashes.push(this.hash);
    }
-    this.hash = {values: [], types: [], contexts: [], ids: []};
+    this.hash = { values: {}, types: [], contexts: [], ids: [] };
  },
  popHash: function() {
    let hash = this.hash;
@@ -561,6 +664,29 @@ JavaScriptCompiler.prototype = {
    }
  },

+  // [registerDecorator]
+  //
+  // On stack, before: hash, program, params..., ...
+  // On stack, after: ...
+  //
+  // Pops off the decorator's parameters, invokes the decorator,
+  // and inserts the decorator into the decorators list.
+  registerDecorator(paramSize, name) {
+    let foundDecorator = this.nameLookup('decorators', name, 'decorator'),
+      options = this.setupHelperArgs(name, paramSize);
+
+    this.decorators.push([
+      'fn = ',
+      this.decorators.functionCall(foundDecorator, '', [
+        'fn',
+        'props',
+        'container',
+        options
+      ]),
+      ' || fn;'
+    ]);
+  },
+
  // [invokeHelper]
  //
  // On stack, before: hash, inverse, program, params..., ...
@@ -572,18 +698,43 @@ JavaScriptCompiler.prototype = {
  // If the helper is not found, `helperMissing` is called.
  invokeHelper: function(paramSize, name, isSimple) {
    let nonHelper = this.popStack(),
-        helper = this.setupHelper(paramSize, name),
-        simple = isSimple ? [helper.name, ' || '] : '';
+      helper = this.setupHelper(paramSize, name);

-    let lookup = ['('].concat(simple, nonHelper);
-    if (!this.options.strict) {
-      lookup.push(' || ', this.aliasable('helpers.helperMissing'));
+    let possibleFunctionCalls = [];
+
+    if (isSimple) {
+      // direct call to helper
+      possibleFunctionCalls.push(helper.name);
+    }
+    // call a function from the input object
+    possibleFunctionCalls.push(nonHelper);
+    if (!this.options.strict) {
+      possibleFunctionCalls.push(
+        this.aliasable('container.hooks.helperMissing')
+      );
    }
-    lookup.push(')');

-    this.push(this.source.functionCall(lookup, 'call', helper.callParams));
+    let functionLookupCode = [
+      '(',
+      this.itemsSeparatedBy(possibleFunctionCalls, '||'),
+      ')'
+    ];
+    let functionCall = this.source.functionCall(
+      functionLookupCode,
+      'call',
+      helper.callParams
+    );
+    this.push(functionCall);
  },

+  itemsSeparatedBy: function(items, separator) {
+    let result = [];
+    result.push(items[0]);
+    for (let i = 1; i < items.length; i++) {
+      result.push(separator, items[i]);
+    }
+    return result;
+  },
  // [invokeKnownHelper]
  //
  // On stack, before: hash, inverse, program, params..., ...
@@ -616,22 +767,31 @@ JavaScriptCompiler.prototype = {
    this.emptyHash();
    let helper = this.setupHelper(0, name, helperCall);

-    let helperName = this.lastHelper = this.nameLookup('helpers', name, 'helper');
+    let helperName = (this.lastHelper = this.nameLookup(
+      'helpers',
+      name,
+      'helper'
+    ));

    let lookup = ['(', '(helper = ', helperName, ' || ', nonHelper, ')'];
    if (!this.options.strict) {
      lookup[0] = '(helper = ';
      lookup.push(
        ' != null ? helper : ',
-        this.aliasable('helpers.helperMissing')
+        this.aliasable('container.hooks.helperMissing')
      );
    }

    this.push([
-        '(', lookup,
-        (helper.paramsInit ? ['),(', helper.paramsInit] : []), '),',
-        '(typeof helper === ', this.aliasable('"function"'), ' ? ',
-        this.source.functionCall('helper', 'call', helper.callParams), ' : helper))'
+      '(',
+      lookup,
+      helper.paramsInit ? ['),(', helper.paramsInit] : [],
+      '),',
+      '(typeof helper === ',
+      this.aliasable('"function"'),
+      ' ? ',
+      this.source.functionCall('helper', 'call', helper.callParams),
+      ' : helper))'
    ]);
  },

@@ -644,7 +804,7 @@ JavaScriptCompiler.prototype = {
  // and pushes the result of the invocation back.
  invokePartial: function(isDynamic, name, indent) {
    let params = [],
-        options = this.setupParams(name, 1, params, false);
+      options = this.setupParams(name, 1, params);

    if (isDynamic) {
      name = this.popStack();
@@ -656,6 +816,7 @@ JavaScriptCompiler.prototype = {
    }
    options.helpers = 'helpers';
    options.partials = 'partials';
+    options.decorators = 'container.decorators';

    if (!isDynamic) {
      params.unshift(this.nameLookup('partials', name, 'partial'));
@@ -669,7 +830,7 @@ JavaScriptCompiler.prototype = {
    options = this.objectLiteral(options);
    params.push(options);

-    this.push(this.source.functionCall('this.invokePartial', '', params));
+    this.push(this.source.functionCall('container.invokePartial', '', params));
  },

  // [assignToHash]
@@ -680,9 +841,9 @@ JavaScriptCompiler.prototype = {
  // Pops a value off the stack and assigns it to the current hash
  assignToHash: function(key) {
    let value = this.popStack(),
-        context,
-        type,
-        id;
+      context,
+      type,
+      id;

    if (this.trackIds) {
      id = this.popStack();
@@ -708,8 +869,13 @@ JavaScriptCompiler.prototype = {
  pushId: function(type, name, child) {
    if (type === 'BlockParam') {
      this.pushStackLiteral(
-          'blockParams[' + name[0] + '].path[' + name[1] + ']'
-          + (child ? ' + ' + JSON.stringify('.' + child) : ''));
+        'blockParams[' +
+          name[0] +
+          '].path[' +
+          name[1] +
+          ']' +
+          (child ? ' + ' + JSON.stringify('.' + child) : '')
+      );
    } else if (type === 'PathExpression') {
      this.pushString(name);
    } else if (type === 'SubExpression') {
@@ -724,30 +890,40 @@ JavaScriptCompiler.prototype = {
  compiler: JavaScriptCompiler,

  compileChildren: function(environment, options) {
-    let children = environment.children, child, compiler;
+    let children = environment.children,
+      child,
+      compiler;

    for (let i = 0, l = children.length; i < l; i++) {
      child = children[i];
-      compiler = new this.compiler();    // eslint-disable-line new-cap
+      compiler = new this.compiler(); // eslint-disable-line new-cap

-      let index = this.matchExistingProgram(child);
+      let existing = this.matchExistingProgram(child);

-      if (index == null) {
-        this.context.programs.push('');     // Placeholder to prevent name conflicts for nested children
-        index = this.context.programs.length;
+      if (existing == null) {
+        this.context.programs.push(''); // Placeholder to prevent name conflicts for nested children
+        let index = this.context.programs.length;
        child.index = index;
        child.name = 'program' + index;
-        this.context.programs[index] = compiler.compile(child, options, this.context, !this.precompile);
+        this.context.programs[index] = compiler.compile(
+          child,
+          options,
+          this.context,
+          !this.precompile
+        );
+        this.context.decorators[index] = compiler.decorators;
        this.context.environments[index] = child;

        this.useDepths = this.useDepths || compiler.useDepths;
        this.useBlockParams = this.useBlockParams || compiler.useBlockParams;
+        child.useDepths = this.useDepths;
+        child.useBlockParams = this.useBlockParams;
      } else {
-        child.index = index;
-        child.name = 'program' + index;
+        child.index = existing.index;
+        child.name = 'program' + existing.index;

-        this.useDepths = this.useDepths || child.useDepths;
-        this.useBlockParams = this.useBlockParams || child.useBlockParams;
+        this.useDepths = this.useDepths || existing.useDepths;
+        this.useBlockParams = this.useBlockParams || existing.useBlockParams;
      }
    }
  },
@@ -755,14 +931,14 @@ JavaScriptCompiler.prototype = {
    for (let i = 0, len = this.context.environments.length; i < len; i++) {
      let environment = this.context.environments[i];
      if (environment && environment.equals(child)) {
-        return i;
+        return environment;
      }
    }
  },

  programExpression: function(guid) {
    let child = this.environment.children[guid],
-        programParams = [child.index, 'data', child.blockParams];
+      programParams = [child.index, 'data', child.blockParams];

    if (this.useBlockParams || this.useDepths) {
      programParams.push('blockParams');
@@ -771,7 +947,7 @@ JavaScriptCompiler.prototype = {
      programParams.push('depths');
    }

-    return 'this.program(' + programParams.join(', ') + ')';
+    return 'container.program(' + programParams.join(', ') + ')';
  },

  useRegister: function(name) {
@@ -797,7 +973,11 @@ JavaScriptCompiler.prototype = {
  pushSource: function(source) {
    if (this.pendingContent) {
      this.source.push(
-          this.appendToBuffer(this.source.quotedString(this.pendingContent), this.pendingLocation));
+        this.appendToBuffer(
+          this.source.quotedString(this.pendingContent),
+          this.pendingLocation
+        )
+      );
      this.pendingContent = undefined;
    }

@@ -808,9 +988,9 @@ JavaScriptCompiler.prototype = {

  replaceStack: function(callback) {
    let prefix = ['('],
-        stack,
-        createdStack,
-        usedLiteral;
+      stack,
+      createdStack,
+      usedLiteral;

    /* istanbul ignore next */
    if (!this.isInline()) {
@@ -847,7 +1027,9 @@ JavaScriptCompiler.prototype = {

  incrStack: function() {
    this.stackSlot++;
-    if (this.stackSlot > this.stackVars.length) { this.stackVars.push('stack' + this.stackSlot); }
+    if (this.stackSlot > this.stackVars.length) {
+      this.stackVars.push('stack' + this.stackSlot);
+    }
    return this.topStackName();
  },
  topStackName: function() {
@@ -874,9 +1056,9 @@ JavaScriptCompiler.prototype = {

  popStack: function(wrapped) {
    let inline = this.isInline(),
-        item = (inline ? this.inlineStack : this.compileStack).pop();
+      item = (inline ? this.inlineStack : this.compileStack).pop();

-    if (!wrapped && (item instanceof Literal)) {
+    if (!wrapped && item instanceof Literal) {
      return item.value;
    } else {
      if (!inline) {
@@ -891,8 +1073,8 @@ JavaScriptCompiler.prototype = {
  },

  topStack: function() {
-    let stack = (this.isInline() ? this.inlineStack : this.compileStack),
-        item = stack[stack.length - 1];
+    let stack = this.isInline() ? this.inlineStack : this.compileStack,
+      item = stack[stack.length - 1];

    /* istanbul ignore if */
    if (item instanceof Literal) {
@@ -934,19 +1116,33 @@ JavaScriptCompiler.prototype = {

  setupHelper: function(paramSize, name, blockHelper) {
    let params = [],
-        paramsInit = this.setupHelperArgs(name, paramSize, params, blockHelper);
-    let foundHelper = this.nameLookup('helpers', name, 'helper');
+      paramsInit = this.setupHelperArgs(name, paramSize, params, blockHelper);
+    let foundHelper = this.nameLookup('helpers', name, 'helper'),
+      callContext = this.aliasable(
+        `${this.contextName(0)} != null ? ${this.contextName(
+          0
+        )} : (container.nullContext || {})`
+      );

    return {
      params: params,
      paramsInit: paramsInit,
      name: foundHelper,
-      callParams: [this.contextName(0)].concat(params)
+      callParams: [callContext].concat(params)
    };
  },

  setupParams: function(helper, paramSize, params) {
-    let options = {}, contexts = [], types = [], ids = [], param;
+    let options = {},
+      contexts = [],
+      types = [],
+      ids = [],
+      objectArgs = !params,
+      param;
+
+    if (objectArgs) {
+      params = [];
+    }

    options.name = this.quotedString(helper);
    options.hash = this.popStack();
@@ -960,13 +1156,13 @@ JavaScriptCompiler.prototype = {
    }

    let inverse = this.popStack(),
-        program = this.popStack();
+      program = this.popStack();

    // Avoid setting fn and inverse if neither are set. This allows
    // helpers to do a check for `if (options.fn)`
    if (program || inverse) {
-      options.fn = program || 'this.noop';
-      options.inverse = inverse || 'this.noop';
+      options.fn = program || 'container.noop';
+      options.inverse = inverse || 'container.noop';
    }

    // The parameters go on to the stack in order (making sure that they are evaluated in order)
@@ -985,6 +1181,10 @@ JavaScriptCompiler.prototype = {
      }
    }

+    if (objectArgs) {
+      options.args = this.source.generateArray(params);
+    }
+
    if (this.trackIds) {
      options.ids = this.source.generateArray(ids);
    }
@@ -1003,20 +1203,22 @@ JavaScriptCompiler.prototype = {
  },

  setupHelperArgs: function(helper, paramSize, params, useRegister) {
-    let options = this.setupParams(helper, paramSize, params, true);
+    let options = this.setupParams(helper, paramSize, params);
+    options.loc = JSON.stringify(this.source.currentLocation);
    options = this.objectLiteral(options);
    if (useRegister) {
      this.useRegister('options');
      params.push('options');
      return ['options=', options];
-    } else {
+    } else if (params) {
      params.push(options);
      return '';
+    } else {
+      return options;
    }
  }
 };

-
 (function() {
  const reservedWords = (
    'break else new var' +
@@ -1037,21 +1239,27 @@ JavaScriptCompiler.prototype = {
    ' null true false'
  ).split(' ');

-  const compilerWords = JavaScriptCompiler.RESERVED_WORDS = {};
+  const compilerWords = (JavaScriptCompiler.RESERVED_WORDS = {});

  for (let i = 0, l = reservedWords.length; i < l; i++) {
    compilerWords[reservedWords[i]] = true;
  }
-}());
+})();

+/**
+ * @deprecated May be removed in the next major version
+ */
 JavaScriptCompiler.isValidJavaScriptVariableName = function(name) {
-  return !JavaScriptCompiler.RESERVED_WORDS[name] && (/^[a-zA-Z_$][0-9a-zA-Z_$]*$/).test(name);
+  return (
+    !JavaScriptCompiler.RESERVED_WORDS[name] &&
+    /^[a-zA-Z_$][0-9a-zA-Z_$]*$/.test(name)
+  );
 };

 function strictLookup(requireTerminal, compiler, parts, type) {
  let stack = compiler.popStack(),
-      i = 0,
-      len = parts.length;
+    i = 0,
+    len = parts.length;
  if (requireTerminal) {
    len--;
  }
@@ -1061,7 +1269,16 @@ function strictLookup(requireTerminal, compiler, parts, type) {
  }

  if (requireTerminal) {
-    return [compiler.aliasable('this.strict'), '(', stack, ', ', compiler.quotedString(parts[i]), ')'];
+    return [
+      compiler.aliasable('container.strict'),
+      '(',
+      stack,
+      ', ',
+      compiler.quotedString(parts[i]),
+      ', ',
+      JSON.stringify(compiler.source.currentLocation),
+      ' )'
+    ];
  } else {
    return stack;
  }
@@ -1,4 +1,4 @@
-/*eslint-disable new-cap */
+/* eslint-disable new-cap */
 import Visitor from './visitor';

 export function print(ast) {
@@ -15,29 +15,30 @@ PrintVisitor.prototype.pad = function(string) {
  let out = '';

  for (let i = 0, l = this.padding; i < l; i++) {
-    out = out + '  ';
+    out += '  ';
  }

-  out = out + string + '\n';
+  out += string + '\n';
  return out;
 };

 PrintVisitor.prototype.Program = function(program) {
  let out = '',
-      body = program.body,
-      i, l;
+    body = program.body,
+    i,
+    l;

  if (program.blockParams) {
    let blockParams = 'BLOCK PARAMS: [';
    for (i = 0, l = program.blockParams.length; i < l; i++) {
-       blockParams += ' ' + program.blockParams[i];
+      blockParams += ' ' + program.blockParams[i];
    }
    blockParams += ' ]';
    out += this.pad(blockParams);
  }

  for (i = 0, l = body.length; i < l; i++) {
-    out = out + this.accept(body[i]);
+    out += this.accept(body[i]);
  }

  this.padding--;
@@ -48,26 +49,37 @@ PrintVisitor.prototype.Program = function(program) {
 PrintVisitor.prototype.MustacheStatement = function(mustache) {
  return this.pad('{{ ' + this.SubExpression(mustache) + ' }}');
 };
+PrintVisitor.prototype.Decorator = function(mustache) {
+  return this.pad('{{ DIRECTIVE ' + this.SubExpression(mustache) + ' }}');
+};

-PrintVisitor.prototype.BlockStatement = function(block) {
+PrintVisitor.prototype.BlockStatement = PrintVisitor.prototype.DecoratorBlock = function(
+  block
+) {
  let out = '';

-  out = out + this.pad('BLOCK:');
+  out += this.pad(
+    (block.type === 'DecoratorBlock' ? 'DIRECTIVE ' : '') + 'BLOCK:'
+  );
  this.padding++;
-  out = out + this.pad(this.SubExpression(block));
+  out += this.pad(this.SubExpression(block));
  if (block.program) {
-    out = out + this.pad('PROGRAM:');
+    out += this.pad('PROGRAM:');
    this.padding++;
-    out = out + this.accept(block.program);
+    out += this.accept(block.program);
    this.padding--;
  }
  if (block.inverse) {
-    if (block.program) { this.padding++; }
-    out = out + this.pad('{{^}}');
+    if (block.program) {
+      this.padding++;
+    }
+    out += this.pad('{{^}}');
    this.padding++;
-    out = out + this.accept(block.inverse);
+    out += this.accept(block.inverse);
    this.padding--;
-    if (block.program) { this.padding--; }
+    if (block.program) {
+      this.padding--;
+    }
  }
  this.padding--;

@@ -84,6 +96,22 @@ PrintVisitor.prototype.PartialStatement = function(partial) {
  }
  return this.pad('{{> ' + content + ' }}');
 };
+PrintVisitor.prototype.PartialBlockStatement = function(partial) {
+  let content = 'PARTIAL BLOCK:' + partial.name.original;
+  if (partial.params[0]) {
+    content += ' ' + this.accept(partial.params[0]);
+  }
+  if (partial.hash) {
+    content += ' ' + this.accept(partial.hash);
+  }
+
+  content += ' ' + this.pad('PROGRAM:');
+  this.padding++;
+  content += this.accept(partial.program);
+  this.padding--;
+
+  return this.pad('{{> ' + content + ' }}');
+};

 PrintVisitor.prototype.ContentStatement = function(content) {
  return this.pad("CONTENT[ '" + content.value + "' ]");
@@ -95,8 +123,8 @@ PrintVisitor.prototype.CommentStatement = function(comment) {

 PrintVisitor.prototype.SubExpression = function(sexpr) {
  let params = sexpr.params,
-      paramStrings = [],
-      hash;
+    paramStrings = [],
+    hash;

  for (let i = 0, l = params.length; i < l; i++) {
    paramStrings.push(this.accept(params[i]));
@@ -114,7 +142,6 @@ PrintVisitor.prototype.PathExpression = function(id) {
  return (id.data ? '@' : '') + 'PATH:' + path;
 };

-
 PrintVisitor.prototype.StringLiteral = function(string) {
  return '"' + string.value + '"';
 };
@@ -137,7 +164,7 @@ PrintVisitor.prototype.NullLiteral = function() {

 PrintVisitor.prototype.Hash = function(hash) {
  let pairs = hash.pairs,
-      joinedPairs = [];
+    joinedPairs = [];

  for (let i = 0, l = pairs.length; i < l; i++) {
    joinedPairs.push(this.accept(pairs[i]));
@@ -148,4 +175,4 @@ PrintVisitor.prototype.Hash = function(hash) {
 PrintVisitor.prototype.HashPair = function(pair) {
  return pair.key + '=' + this.accept(pair.value);
 };
-/*eslint-enable new-cap */
+/* eslint-enable new-cap */
@@ -1,5 +1,4 @@
 import Exception from '../exception';
-import AST from './ast';

 function Visitor() {
  this.parents = [];
@@ -13,9 +12,17 @@ Visitor.prototype = {
  acceptKey: function(node, name) {
    let value = this.accept(node[name]);
    if (this.mutating) {
-      // Hacky sanity check:
-      if (value && (!value.type || !AST[value.type])) {
-        throw new Exception('Unexpected node type "' + value.type + '" found when accepting ' + name + ' on ' + node.type);
+      // Hacky sanity check: This may have a few false positives for type for the helper
+      // methods but will generally do the right thing without a lot of overhead.
+      if (value && !Visitor.prototype[value.type]) {
+        throw new Exception(
+          'Unexpected node type "' +
+            value.type +
+            '" found when accepting ' +
+            name +
+            ' on ' +
+            node.type
+        );
      }
      node[name] = value;
    }
@@ -50,6 +57,11 @@ Visitor.prototype = {
      return;
    }

+    /* istanbul ignore next: Sanity code */
+    if (!this[object.type]) {
+      throw new Exception('Unknown type: ' + object.type, object);
+    }
+
    if (this.current) {
      this.parents.unshift(this.current);
    }
@@ -70,35 +82,23 @@ Visitor.prototype = {
    this.acceptArray(program.body);
  },

-  MustacheStatement: function(mustache) {
-    this.acceptRequired(mustache, 'path');
-    this.acceptArray(mustache.params);
-    this.acceptKey(mustache, 'hash');
-  },
+  MustacheStatement: visitSubExpression,
+  Decorator: visitSubExpression,

-  BlockStatement: function(block) {
-    this.acceptRequired(block, 'path');
-    this.acceptArray(block.params);
-    this.acceptKey(block, 'hash');
+  BlockStatement: visitBlock,
+  DecoratorBlock: visitBlock,

-    this.acceptKey(block, 'program');
-    this.acceptKey(block, 'inverse');
-  },
+  PartialStatement: visitPartial,
+  PartialBlockStatement: function(partial) {
+    visitPartial.call(this, partial);

-  PartialStatement: function(partial) {
-    this.acceptRequired(partial, 'name');
-    this.acceptArray(partial.params);
-    this.acceptKey(partial, 'hash');
+    this.acceptKey(partial, 'program');
  },

  ContentStatement: function(/* content */) {},
  CommentStatement: function(/* comment */) {},

-  SubExpression: function(sexpr) {
-    this.acceptRequired(sexpr, 'path');
-    this.acceptArray(sexpr.params);
-    this.acceptKey(sexpr, 'hash');
-  },
+  SubExpression: visitSubExpression,

  PathExpression: function(/* path */) {},

@@ -116,4 +116,21 @@ Visitor.prototype = {
  }
 };

+function visitSubExpression(mustache) {
+  this.acceptRequired(mustache, 'path');
+  this.acceptArray(mustache.params);
+  this.acceptKey(mustache, 'hash');
+}
+function visitBlock(block) {
+  visitSubExpression.call(this, block);
+
+  this.acceptKey(block, 'program');
+  this.acceptKey(block, 'inverse');
+}
+function visitPartial(partial) {
+  this.acceptRequired(partial, 'name');
+  this.acceptArray(partial.params);
+  this.acceptKey(partial, 'hash');
+}
+
 export default Visitor;
@@ -1,28 +1,31 @@
 import Visitor from './visitor';

-function WhitespaceControl() {
+function WhitespaceControl(options = {}) {
+  this.options = options;
 }
 WhitespaceControl.prototype = new Visitor();

 WhitespaceControl.prototype.Program = function(program) {
+  const doStandalone = !this.options.ignoreStandalone;
+
  let isRoot = !this.isRootSeen;
  this.isRootSeen = true;

  let body = program.body;
  for (let i = 0, l = body.length; i < l; i++) {
    let current = body[i],
-        strip = this.accept(current);
+      strip = this.accept(current);

    if (!strip) {
      continue;
    }

    let _isPrevWhitespace = isPrevWhitespace(body, i, isRoot),
-        _isNextWhitespace = isNextWhitespace(body, i, isRoot),
-
-        openStandalone = strip.openStandalone && _isPrevWhitespace,
-        closeStandalone = strip.closeStandalone && _isNextWhitespace,
-        inlineStandalone = strip.inlineStandalone && _isPrevWhitespace && _isNextWhitespace;
+      _isNextWhitespace = isNextWhitespace(body, i, isRoot),
+      openStandalone = strip.openStandalone && _isPrevWhitespace,
+      closeStandalone = strip.closeStandalone && _isNextWhitespace,
+      inlineStandalone =
+        strip.inlineStandalone && _isPrevWhitespace && _isNextWhitespace;

    if (strip.close) {
      omitRight(body, i, true);
@@ -31,24 +34,24 @@ WhitespaceControl.prototype.Program = function(program) {
      omitLeft(body, i, true);
    }

-    if (inlineStandalone) {
+    if (doStandalone && inlineStandalone) {
      omitRight(body, i);

      if (omitLeft(body, i)) {
        // If we are on a standalone node, save the indent info for partials
        if (current.type === 'PartialStatement') {
          // Pull out the whitespace from the final line
-          current.indent = (/([ \t]+$)/).exec(body[i - 1].original)[1];
+          current.indent = /([ \t]+$)/.exec(body[i - 1].original)[1];
        }
      }
    }
-    if (openStandalone) {
+    if (doStandalone && openStandalone) {
      omitRight((current.program || current.inverse).body);

      // Strip out the previous content node if it's whitespace only
      omitLeft(body, i);
    }
-    if (closeStandalone) {
+    if (doStandalone && closeStandalone) {
      // Always strip the next node
      omitRight(body, i);

@@ -58,15 +61,18 @@ WhitespaceControl.prototype.Program = function(program) {

  return program;
 };
-WhitespaceControl.prototype.BlockStatement = function(block) {
+
+WhitespaceControl.prototype.BlockStatement = WhitespaceControl.prototype.DecoratorBlock = WhitespaceControl.prototype.PartialBlockStatement = function(
+  block
+) {
  this.accept(block.program);
  this.accept(block.inverse);

  // Find the inverse program that is involed with whitespace stripping.
  let program = block.program || block.inverse,
-      inverse = block.program && block.inverse,
-      firstInverse = inverse,
-      lastInverse = inverse;
+    inverse = block.program && block.inverse,
+    firstInverse = inverse,
+    lastInverse = inverse;

  if (inverse && inverse.chained) {
    firstInverse = inverse.body[0].program;
@@ -106,8 +112,11 @@ WhitespaceControl.prototype.BlockStatement = function(block) {
    }

    // Find standalone else statments
-    if (isPrevWhitespace(program.body)
-        && isNextWhitespace(firstInverse.body)) {
+    if (
+      !this.options.ignoreStandalone &&
+      isPrevWhitespace(program.body) &&
+      isNextWhitespace(firstInverse.body)
+    ) {
      omitLeft(program.body);
      omitRight(firstInverse.body);
    }
@@ -118,12 +127,15 @@ WhitespaceControl.prototype.BlockStatement = function(block) {
  return strip;
 };

-WhitespaceControl.prototype.MustacheStatement = function(mustache) {
+WhitespaceControl.prototype.Decorator = WhitespaceControl.prototype.MustacheStatement = function(
+  mustache
+) {
  return mustache.strip;
 };

-WhitespaceControl.prototype.PartialStatement =
-    WhitespaceControl.prototype.CommentStatement = function(node) {
+WhitespaceControl.prototype.PartialStatement = WhitespaceControl.prototype.CommentStatement = function(
+  node
+) {
  /* istanbul ignore next */
  let strip = node.strip || {};
  return {
@@ -133,7 +145,6 @@ WhitespaceControl.prototype.PartialStatement =
  };
 };

-
 function isPrevWhitespace(body, i, isRoot) {
  if (i === undefined) {
    i = body.length;
@@ -142,13 +153,15 @@ function isPrevWhitespace(body, i, isRoot) {
  // Nodes that end with newlines are considered whitespace (but are special
  // cased for strip operations)
  let prev = body[i - 1],
-      sibling = body[i - 2];
+    sibling = body[i - 2];
  if (!prev) {
    return isRoot;
  }

  if (prev.type === 'ContentStatement') {
-    return (sibling || !isRoot ? (/\r?\n\s*?$/) : (/(^|\r?\n)\s*?$/)).test(prev.original);
+    return (sibling || !isRoot ? /\r?\n\s*?$/ : /(^|\r?\n)\s*?$/).test(
+      prev.original
+    );
  }
 }
 function isNextWhitespace(body, i, isRoot) {
@@ -157,13 +170,15 @@ function isNextWhitespace(body, i, isRoot) {
  }

  let next = body[i + 1],
-      sibling = body[i + 2];
+    sibling = body[i + 2];
  if (!next) {
    return isRoot;
  }

  if (next.type === 'ContentStatement') {
-    return (sibling || !isRoot ? (/^\s*?\r?\n/) : (/^\s*?(\r?\n|$)/)).test(next.original);
+    return (sibling || !isRoot ? /^\s*?\r?\n/ : /^\s*?(\r?\n|$)/).test(
+      next.original
+    );
  }
 }

@@ -176,12 +191,19 @@ function isNextWhitespace(body, i, isRoot) {
 // content is met.
 function omitRight(body, i, multiple) {
  let current = body[i == null ? 0 : i + 1];
-  if (!current || current.type !== 'ContentStatement' || (!multiple && current.rightStripped)) {
+  if (
+    !current ||
+    current.type !== 'ContentStatement' ||
+    (!multiple && current.rightStripped)
+  ) {
    return;
  }

  let original = current.value;
-  current.value = current.value.replace(multiple ? (/^\s+/) : (/^[ \t]*\r?\n?/), '');
+  current.value = current.value.replace(
+    multiple ? /^\s+/ : /^[ \t]*\r?\n?/,
+    ''
+  );
  current.rightStripped = current.value !== original;
 }

@@ -194,13 +216,17 @@ function omitRight(body, i, multiple) {
 // content is met.
 function omitLeft(body, i, multiple) {
  let current = body[i == null ? body.length - 1 : i - 1];
-  if (!current || current.type !== 'ContentStatement' || (!multiple && current.leftStripped)) {
+  if (
+    !current ||
+    current.type !== 'ContentStatement' ||
+    (!multiple && current.leftStripped)
+  ) {
    return;
  }

-  // We omit the last node if it's whitespace only and not preceeded by a non-content node.
+  // We omit the last node if it's whitespace only and not preceded by a non-content node.
  let original = current.value;
-  current.value = current.value.replace(multiple ? (/\s+$/) : (/[ \t]+$/), '');
+  current.value = current.value.replace(multiple ? /\s+$/ : /[ \t]+$/, '');
  current.leftStripped = current.value !== original;
  return current.leftStripped;
 }
@@ -0,0 +1,5 @@
+import registerInline from './decorators/inline';
+
+export function registerDefaultDecorators(instance) {
+  registerInline(instance);
+}
@@ -0,0 +1,22 @@
+import { extend } from '../utils';
+
+export default function(instance) {
+  instance.registerDecorator('inline', function(fn, props, container, options) {
+    let ret = fn;
+    if (!props.partials) {
+      props.partials = {};
+      ret = function(context, options) {
+        // Create a new partials stack frame prior to exec.
+        let original = container.partials;
+        container.partials = extend({}, original, props.partials);
+        let ret = fn(context, options);
+        container.partials = original;
+        return ret;
+      };
+    }
+
+    props.partials[options.args[0]] = options.fn;
+
+    return ret;
+  });
+}
@@ -1,13 +1,26 @@
-
-const errorProps = ['description', 'fileName', 'lineNumber', 'message', 'name', 'number', 'stack'];
+const errorProps = [
+  'description',
+  'fileName',
+  'lineNumber',
+  'endLineNumber',
+  'message',
+  'name',
+  'number',
+  'stack'
+];

 function Exception(message, node) {
  let loc = node && node.loc,
-      line,
-      column;
+    line,
+    endLineNumber,
+    column,
+    endColumn;
+
  if (loc) {
    line = loc.start.line;
+    endLineNumber = loc.end.line;
    column = loc.start.column;
+    endColumn = loc.end.column;

    message += ' - ' + line + ':' + column;
  }
@@ -19,13 +32,34 @@ function Exception(message, node) {
    this[errorProps[idx]] = tmp[errorProps[idx]];
  }

+  /* istanbul ignore else */
  if (Error.captureStackTrace) {
    Error.captureStackTrace(this, Exception);
  }

-  if (loc) {
-    this.lineNumber = line;
-    this.column = column;
+  try {
+    if (loc) {
+      this.lineNumber = line;
+      this.endLineNumber = endLineNumber;
+
+      // Work around issue under safari where we can't directly set the column value
+      /* istanbul ignore next */
+      if (Object.defineProperty) {
+        Object.defineProperty(this, 'column', {
+          value: column,
+          enumerable: true
+        });
+        Object.defineProperty(this, 'endColumn', {
+          value: endColumn,
+          enumerable: true
+        });
+      } else {
+        this.column = column;
+        this.endColumn = endColumn;
+      }
+    }
+  } catch (nop) {
+    /* Ignore if the browser is very particular */
  }
 }

@@ -0,0 +1,26 @@
+import registerBlockHelperMissing from './helpers/block-helper-missing';
+import registerEach from './helpers/each';
+import registerHelperMissing from './helpers/helper-missing';
+import registerIf from './helpers/if';
+import registerLog from './helpers/log';
+import registerLookup from './helpers/lookup';
+import registerWith from './helpers/with';
+
+export function registerDefaultHelpers(instance) {
+  registerBlockHelperMissing(instance);
+  registerEach(instance);
+  registerHelperMissing(instance);
+  registerIf(instance);
+  registerLog(instance);
+  registerLookup(instance);
+  registerWith(instance);
+}
+
+export function moveHelperToHooks(instance, helperName, keepHelper) {
+  if (instance.helpers[helperName]) {
+    instance.hooks[helperName] = instance.helpers[helperName];
+    if (!keepHelper) {
+      delete instance.helpers[helperName];
+    }
+  }
+}
@@ -0,0 +1,35 @@
+import { appendContextPath, createFrame, isArray } from '../utils';
+
+export default function(instance) {
+  instance.registerHelper('blockHelperMissing', function(context, options) {
+    let inverse = options.inverse,
+      fn = options.fn;
+
+    if (context === true) {
+      return fn(this);
+    } else if (context === false || context == null) {
+      return inverse(this);
+    } else if (isArray(context)) {
+      if (context.length > 0) {
+        if (options.ids) {
+          options.ids = [options.name];
+        }
+
+        return instance.helpers.each(context, options);
+      } else {
+        return inverse(this);
+      }
+    } else {
+      if (options.data && options.ids) {
+        let data = createFrame(options.data);
+        data.contextPath = appendContextPath(
+          options.data.contextPath,
+          options.name
+        );
+        options = { data: data };
+      }
+
+      return fn(context, options);
+    }
+  });
+}
@@ -0,0 +1,101 @@
+import {
+  appendContextPath,
+  blockParams,
+  createFrame,
+  isArray,
+  isFunction
+} from '../utils';
+import Exception from '../exception';
+
+export default function(instance) {
+  instance.registerHelper('each', function(context, options) {
+    if (!options) {
+      throw new Exception('Must pass iterator to #each');
+    }
+
+    let fn = options.fn,
+      inverse = options.inverse,
+      i = 0,
+      ret = '',
+      data,
+      contextPath;
+
+    if (options.data && options.ids) {
+      contextPath =
+        appendContextPath(options.data.contextPath, options.ids[0]) + '.';
+    }
+
+    if (isFunction(context)) {
+      context = context.call(this);
+    }
+
+    if (options.data) {
+      data = createFrame(options.data);
+    }
+
+    function execIteration(field, index, last) {
+      if (data) {
+        data.key = field;
+        data.index = index;
+        data.first = index === 0;
+        data.last = !!last;
+
+        if (contextPath) {
+          data.contextPath = contextPath + field;
+        }
+      }
+
+      ret =
+        ret +
+        fn(context[field], {
+          data: data,
+          blockParams: blockParams(
+            [context[field], field],
+            [contextPath + field, null]
+          )
+        });
+    }
+
+    if (context && typeof context === 'object') {
+      if (isArray(context)) {
+        for (let j = context.length; i < j; i++) {
+          if (i in context) {
+            execIteration(i, i, i === context.length - 1);
+          }
+        }
+      } else if (global.Symbol && context[global.Symbol.iterator]) {
+        const newContext = [];
+        const iterator = context[global.Symbol.iterator]();
+        for (let it = iterator.next(); !it.done; it = iterator.next()) {
+          newContext.push(it.value);
+        }
+        context = newContext;
+        for (let j = context.length; i < j; i++) {
+          execIteration(i, i, i === context.length - 1);
+        }
+      } else {
+        let priorKey;
+
+        Object.keys(context).forEach(key => {
+          // We're running the iterations one step out of sync so we can detect
+          // the last iteration without have to scan the object twice and create
+          // an itermediate keys array.
+          if (priorKey !== undefined) {
+            execIteration(priorKey, i - 1);
+          }
+          priorKey = key;
+          i++;
+        });
+        if (priorKey !== undefined) {
+          execIteration(priorKey, i - 1, true);
+        }
+      }
+    }
+
+    if (i === 0) {
+      ret = inverse(this);
+    }
+
+    return ret;
+  });
+}
@@ -0,0 +1,15 @@
+import Exception from '../exception';
+
+export default function(instance) {
+  instance.registerHelper('helperMissing', function(/* [args, ]options */) {
+    if (arguments.length === 1) {
+      // A missing field in a {{foo}} construct.
+      return undefined;
+    } else {
+      // Someone is actually trying to call something, blow up.
+      throw new Exception(
+        'Missing helper: "' + arguments[arguments.length - 1].name + '"'
+      );
+    }
+  });
+}
@@ -0,0 +1,33 @@
+import { isEmpty, isFunction } from '../utils';
+import Exception from '../exception';
+
+export default function(instance) {
+  instance.registerHelper('if', function(conditional, options) {
+    if (arguments.length != 2) {
+      throw new Exception('#if requires exactly one argument');
+    }
+    if (isFunction(conditional)) {
+      conditional = conditional.call(this);
+    }
+
+    // Default behavior is to render the positive path if the value is truthy and not empty.
+    // The `includeZero` option may be set to treat the condtional as purely not empty based on the
+    // behavior of isEmpty. Effectively this determines if 0 is handled by the positive path or negative.
+    if ((!options.hash.includeZero && !conditional) || isEmpty(conditional)) {
+      return options.inverse(this);
+    } else {
+      return options.fn(this);
+    }
+  });
+
+  instance.registerHelper('unless', function(conditional, options) {
+    if (arguments.length != 2) {
+      throw new Exception('#unless requires exactly one argument');
+    }
+    return instance.helpers['if'].call(this, conditional, {
+      fn: options.inverse,
+      inverse: options.fn,
+      hash: options.hash
+    });
+  });
+}
@@ -0,0 +1,19 @@
+export default function(instance) {
+  instance.registerHelper('log', function(/* message, options */) {
+    let args = [undefined],
+      options = arguments[arguments.length - 1];
+    for (let i = 0; i < arguments.length - 1; i++) {
+      args.push(arguments[i]);
+    }
+
+    let level = 1;
+    if (options.hash.level != null) {
+      level = options.hash.level;
+    } else if (options.data && options.data.level != null) {
+      level = options.data.level;
+    }
+    args[0] = level;
+
+    instance.log(...args);
+  });
+}
@@ -0,0 +1,9 @@
+export default function(instance) {
+  instance.registerHelper('lookup', function(obj, field, options) {
+    if (!obj) {
+      // Note for 5.0: Change to "obj == null" in 5.0
+      return obj;
+    }
+    return options.lookupProperty(obj, field);
+  });
+}
@@ -0,0 +1,39 @@
+import {
+  appendContextPath,
+  blockParams,
+  createFrame,
+  isEmpty,
+  isFunction
+} from '../utils';
+import Exception from '../exception';
+
+export default function(instance) {
+  instance.registerHelper('with', function(context, options) {
+    if (arguments.length != 2) {
+      throw new Exception('#with requires exactly one argument');
+    }
+    if (isFunction(context)) {
+      context = context.call(this);
+    }
+
+    let fn = options.fn;
+
+    if (!isEmpty(context)) {
+      let data = options.data;
+      if (options.data && options.ids) {
+        data = createFrame(options.data);
+        data.contextPath = appendContextPath(
+          options.data.contextPath,
+          options.ids[0]
+        );
+      }
+
+      return fn(context, {
+        data: data,
+        blockParams: blockParams([context], [data && data.contextPath])
+      });
+    } else {
+      return options.inverse(this);
+    }
+  });
+}
@@ -0,0 +1,11 @@
+import { extend } from '../utils';
+
+/**
+ * Create a new object with "null"-prototype to avoid truthy results on prototype properties.
+ * The resulting object can be used with "object[property]" to check if a property exists
+ * @param {...object} sources a varargs parameter of source objects that will be merged
+ * @returns {object}
+ */
+export function createNewLookupObject(...sources) {
+  return extend(Object.create(null), ...sources);
+}
@@ -0,0 +1,70 @@
+import { createNewLookupObject } from './create-new-lookup-object';
+import * as logger from '../logger';
+
+const loggedProperties = Object.create(null);
+
+export function createProtoAccessControl(runtimeOptions) {
+  let defaultMethodWhiteList = Object.create(null);
+  defaultMethodWhiteList['constructor'] = false;
+  defaultMethodWhiteList['__defineGetter__'] = false;
+  defaultMethodWhiteList['__defineSetter__'] = false;
+  defaultMethodWhiteList['__lookupGetter__'] = false;
+
+  let defaultPropertyWhiteList = Object.create(null);
+  // eslint-disable-next-line no-proto
+  defaultPropertyWhiteList['__proto__'] = false;
+
+  return {
+    properties: {
+      whitelist: createNewLookupObject(
+        defaultPropertyWhiteList,
+        runtimeOptions.allowedProtoProperties
+      ),
+      defaultValue: runtimeOptions.allowProtoPropertiesByDefault
+    },
+    methods: {
+      whitelist: createNewLookupObject(
+        defaultMethodWhiteList,
+        runtimeOptions.allowedProtoMethods
+      ),
+      defaultValue: runtimeOptions.allowProtoMethodsByDefault
+    }
+  };
+}
+
+export function resultIsAllowed(result, protoAccessControl, propertyName) {
+  if (typeof result === 'function') {
+    return checkWhiteList(protoAccessControl.methods, propertyName);
+  } else {
+    return checkWhiteList(protoAccessControl.properties, propertyName);
+  }
+}
+
+function checkWhiteList(protoAccessControlForType, propertyName) {
+  if (protoAccessControlForType.whitelist[propertyName] !== undefined) {
+    return protoAccessControlForType.whitelist[propertyName] === true;
+  }
+  if (protoAccessControlForType.defaultValue !== undefined) {
+    return protoAccessControlForType.defaultValue;
+  }
+  logUnexpecedPropertyAccessOnce(propertyName);
+  return false;
+}
+
+function logUnexpecedPropertyAccessOnce(propertyName) {
+  if (loggedProperties[propertyName] !== true) {
+    loggedProperties[propertyName] = true;
+    logger.log(
+      'error',
+      `Handlebars: Access has been denied to resolve the property "${propertyName}" because it is not an "own property" of its parent.\n` +
+        `You can add a runtime option to disable the check or this warning:\n` +
+        `See https://handlebarsjs.com/api-reference/runtime-options.html#options-to-control-prototype-access for details`
+    );
+  }
+}
+
+export function resetLoggedProperties() {
+  Object.keys(loggedProperties).forEach(propertyName => {
+    delete loggedProperties[propertyName];
+  });
+}
@@ -0,0 +1,8 @@
+export function wrapHelper(helper, transformOptionsFn) {
+  let wrapper = function(/* dynamic arguments */) {
+    const options = arguments[arguments.length - 1];
+    arguments[arguments.length - 1] = transformOptionsFn(options);
+    return helper.apply(this, arguments);
+  };
+  return wrapper;
+}
@@ -0,0 +1,39 @@
+import { indexOf } from './utils';
+
+let logger = {
+  methodMap: ['debug', 'info', 'warn', 'error'],
+  level: 'info',
+
+  // Maps a given level value to the `methodMap` indexes above.
+  lookupLevel: function(level) {
+    if (typeof level === 'string') {
+      let levelMap = indexOf(logger.methodMap, level.toLowerCase());
+      if (levelMap >= 0) {
+        level = levelMap;
+      } else {
+        level = parseInt(level, 10);
+      }
+    }
+
+    return level;
+  },
+
+  // Can be overridden in the host environment
+  log: function(level, ...message) {
+    level = logger.lookupLevel(level);
+
+    if (
+      typeof console !== 'undefined' &&
+      logger.lookupLevel(logger.level) <= level
+    ) {
+      let method = logger.methodMap[level];
+      // eslint-disable-next-line no-console
+      if (!console[method]) {
+        method = 'log';
+      }
+      console[method](...message); // eslint-disable-line no-console
+    }
+  }
+};
+
+export default logger;
@@ -1,12 +1,12 @@
-/*global window */
 export default function(Handlebars) {
  /* istanbul ignore next */
  let root = typeof global !== 'undefined' ? global : window,
-      $Handlebars = root.Handlebars;
+    $Handlebars = root.Handlebars;
  /* istanbul ignore next */
  Handlebars.noConflict = function() {
    if (root.Handlebars === Handlebars) {
      root.Handlebars = $Handlebars;
    }
+    return Handlebars;
  };
 }
@@ -1,27 +1,51 @@
 import * as Utils from './utils';
 import Exception from './exception';
-import { COMPILER_REVISION, REVISION_CHANGES, createFrame } from './base';
+import {
+  COMPILER_REVISION,
+  createFrame,
+  LAST_COMPATIBLE_COMPILER_REVISION,
+  REVISION_CHANGES
+} from './base';
+import { moveHelperToHooks } from './helpers';
+import { wrapHelper } from './internal/wrapHelper';
+import {
+  createProtoAccessControl,
+  resultIsAllowed
+} from './internal/proto-access';

 export function checkRevision(compilerInfo) {
-  const compilerRevision = compilerInfo && compilerInfo[0] || 1,
-        currentRevision = COMPILER_REVISION;
+  const compilerRevision = (compilerInfo && compilerInfo[0]) || 1,
+    currentRevision = COMPILER_REVISION;

-  if (compilerRevision !== currentRevision) {
-    if (compilerRevision < currentRevision) {
-      const runtimeVersions = REVISION_CHANGES[currentRevision],
-            compilerVersions = REVISION_CHANGES[compilerRevision];
-      throw new Exception('Template was precompiled with an older version of Handlebars than the current runtime. ' +
-            'Please update your precompiler to a newer version (' + runtimeVersions + ') or downgrade your runtime to an older version (' + compilerVersions + ').');
-    } else {
-      // Use the embedded version info since the runtime doesn't know about this revision yet
-      throw new Exception('Template was precompiled with a newer version of Handlebars than the current runtime. ' +
-            'Please update your runtime to a newer version (' + compilerInfo[1] + ').');
-    }
+  if (
+    compilerRevision >= LAST_COMPATIBLE_COMPILER_REVISION &&
+    compilerRevision <= COMPILER_REVISION
+  ) {
+    return;
+  }
+
+  if (compilerRevision < LAST_COMPATIBLE_COMPILER_REVISION) {
+    const runtimeVersions = REVISION_CHANGES[currentRevision],
+      compilerVersions = REVISION_CHANGES[compilerRevision];
+    throw new Exception(
+      'Template was precompiled with an older version of Handlebars than the current runtime. ' +
+        'Please update your precompiler to a newer version (' +
+        runtimeVersions +
+        ') or downgrade your runtime to an older version (' +
+        compilerVersions +
+        ').'
+    );
+  } else {
+    // Use the embedded version info since the runtime doesn't know about this revision yet
+    throw new Exception(
+      'Template was precompiled with a newer version of Handlebars than the current runtime. ' +
+        'Please update your runtime to a newer version (' +
+        compilerInfo[1] +
+        ').'
+    );
  }
 }

-// TODO: Remove this line and break up compilePartial
-
 export function template(templateSpec, env) {
  /* istanbul ignore next */
  if (!env) {
@@ -31,21 +55,44 @@ export function template(templateSpec, env) {
    throw new Exception('Unknown template object: ' + typeof templateSpec);
  }

+  templateSpec.main.decorator = templateSpec.main_d;
+
  // Note: Using env.VM references rather than local var references throughout this section to allow
-  // for external users to override these as psuedo-supported APIs.
+  // for external users to override these as pseudo-supported APIs.
  env.VM.checkRevision(templateSpec.compiler);

+  // backwards compatibility for precompiled templates with compiler-version 7 (<4.3.0)
+  const templateWasPrecompiledWithCompilerV7 =
+    templateSpec.compiler && templateSpec.compiler[0] === 7;
+
  function invokePartialWrapper(partial, context, options) {
    if (options.hash) {
      context = Utils.extend({}, context, options.hash);
+      if (options.ids) {
+        options.ids[0] = true;
+      }
    }
-
    partial = env.VM.resolvePartial.call(this, partial, context, options);
-    let result = env.VM.invokePartial.call(this, partial, context, options);
+
+    let extendedOptions = Utils.extend({}, options, {
+      hooks: this.hooks,
+      protoAccessControl: this.protoAccessControl
+    });
+
+    let result = env.VM.invokePartial.call(
+      this,
+      partial,
+      context,
+      extendedOptions
+    );

    if (result == null && env.compile) {
-      options.partials[options.name] = env.compile(partial, templateSpec.compilerOptions, env);
-      result = options.partials[options.name](context, options);
+      options.partials[options.name] = env.compile(
+        partial,
+        templateSpec.compilerOptions,
+        env
+      );
+      result = options.partials[options.name](context, extendedOptions);
    }
    if (result != null) {
      if (options.indent) {
@@ -61,22 +108,43 @@ export function template(templateSpec, env) {
      }
      return result;
    } else {
-      throw new Exception('The partial ' + options.name + ' could not be compiled when running in runtime-only mode');
+      throw new Exception(
+        'The partial ' +
+          options.name +
+          ' could not be compiled when running in runtime-only mode'
+      );
    }
  }

  // Just add water
  let container = {
-    strict: function(obj, name) {
-      if (!(name in obj)) {
-        throw new Exception('"' + name + '" not defined in ' + obj);
+    strict: function(obj, name, loc) {
+      if (!obj || !(name in obj)) {
+        throw new Exception('"' + name + '" not defined in ' + obj, {
+          loc: loc
+        });
      }
      return obj[name];
    },
+    lookupProperty: function(parent, propertyName) {
+      let result = parent[propertyName];
+      if (result == null) {
+        return result;
+      }
+      if (Object.prototype.hasOwnProperty.call(parent, propertyName)) {
+        return result;
+      }
+
+      if (resultIsAllowed(result, container.protoAccessControl, propertyName)) {
+        return result;
+      }
+      return undefined;
+    },
    lookup: function(depths, name) {
      const len = depths.length;
      for (let i = 0; i < len; i++) {
-        if (depths[i] && depths[i][name] != null) {
+        let result = depths[i] && container.lookupProperty(depths[i], name);
+        if (result != null) {
          return depths[i][name];
        }
      }
@@ -89,15 +157,25 @@ export function template(templateSpec, env) {
    invokePartial: invokePartialWrapper,

    fn: function(i) {
-      return templateSpec[i];
+      let ret = templateSpec[i];
+      ret.decorator = templateSpec[i + '_d'];
+      return ret;
    },

    programs: [],
    program: function(i, data, declaredBlockParams, blockParams, depths) {
      let programWrapper = this.programs[i],
-          fn = this.fn(i);
+        fn = this.fn(i);
      if (data || depths || blockParams || declaredBlockParams) {
-        programWrapper = wrapProgram(this, i, fn, data, declaredBlockParams, blockParams, depths);
+        programWrapper = wrapProgram(
+          this,
+          i,
+          fn,
+          data,
+          declaredBlockParams,
+          blockParams,
+          depths
+        );
      } else if (!programWrapper) {
        programWrapper = this.programs[i] = wrapProgram(this, i, fn);
      }
@@ -110,15 +188,17 @@ export function template(templateSpec, env) {
      }
      return value;
    },
-    merge: function(param, common) {
+    mergeIfNeeded: function(param, common) {
      let obj = param || common;

-      if (param && common && (param !== common)) {
+      if (param && common && param !== common) {
        obj = Utils.extend({}, common, param);
      }

      return obj;
    },
+    // An empty object to use as replacement for null-contexts
+    nullContext: Object.seal({}),

    noop: env.VM.noop,
    compilerInfo: templateSpec.compiler
@@ -132,25 +212,81 @@ export function template(templateSpec, env) {
      data = initData(context, data);
    }
    let depths,
-        blockParams = templateSpec.useBlockParams ? [] : undefined;
+      blockParams = templateSpec.useBlockParams ? [] : undefined;
    if (templateSpec.useDepths) {
-      depths = options.depths ? [context].concat(options.depths) : [context];
+      if (options.depths) {
+        depths =
+          context != options.depths[0]
+            ? [context].concat(options.depths)
+            : options.depths;
+      } else {
+        depths = [context];
+      }
    }

-    return templateSpec.main.call(container, context, container.helpers, container.partials, data, blockParams, depths);
+    function main(context /*, options*/) {
+      return (
+        '' +
+        templateSpec.main(
+          container,
+          context,
+          container.helpers,
+          container.partials,
+          data,
+          blockParams,
+          depths
+        )
+      );
+    }
+
+    main = executeDecorators(
+      templateSpec.main,
+      main,
+      container,
+      options.depths || [],
+      data,
+      blockParams
+    );
+    return main(context, options);
  }
+
  ret.isTop = true;

  ret._setup = function(options) {
    if (!options.partial) {
-      container.helpers = container.merge(options.helpers, env.helpers);
+      let mergedHelpers = Utils.extend({}, env.helpers, options.helpers);
+      wrapHelpersToPassLookupProperty(mergedHelpers, container);
+      container.helpers = mergedHelpers;

      if (templateSpec.usePartial) {
-        container.partials = container.merge(options.partials, env.partials);
+        // Use mergeIfNeeded here to prevent compiling global partials multiple times
+        container.partials = container.mergeIfNeeded(
+          options.partials,
+          env.partials
+        );
      }
+      if (templateSpec.usePartial || templateSpec.useDecorators) {
+        container.decorators = Utils.extend(
+          {},
+          env.decorators,
+          options.decorators
+        );
+      }
+
+      container.hooks = {};
+      container.protoAccessControl = createProtoAccessControl(options);
+
+      let keepHelperInHelpers =
+        options.allowCallsToHelperMissing ||
+        templateWasPrecompiledWithCompilerV7;
+      moveHelperToHooks(container, 'helperMissing', keepHelperInHelpers);
+      moveHelperToHooks(container, 'blockHelperMissing', keepHelperInHelpers);
    } else {
+      container.protoAccessControl = options.protoAccessControl; // internal option
      container.helpers = options.helpers;
      container.partials = options.partials;
+      container.decorators = options.decorators;
+      container.hooks = options.hooks;
    }
  };

@@ -162,29 +298,67 @@ export function template(templateSpec, env) {
      throw new Exception('must pass parent depths');
    }

-    return wrapProgram(container, i, templateSpec[i], data, 0, blockParams, depths);
+    return wrapProgram(
+      container,
+      i,
+      templateSpec[i],
+      data,
+      0,
+      blockParams,
+      depths
+    );
  };
  return ret;
 }

-export function wrapProgram(container, i, fn, data, declaredBlockParams, blockParams, depths) {
+export function wrapProgram(
+  container,
+  i,
+  fn,
+  data,
+  declaredBlockParams,
+  blockParams,
+  depths
+) {
  function prog(context, options = {}) {
-    return fn.call(container,
-        context,
-        container.helpers, container.partials,
-        options.data || data,
-        blockParams && [options.blockParams].concat(blockParams),
-        depths && [context].concat(depths));
+    let currentDepths = depths;
+    if (
+      depths &&
+      context != depths[0] &&
+      !(context === container.nullContext && depths[0] === null)
+    ) {
+      currentDepths = [context].concat(depths);
+    }
+
+    return fn(
+      container,
+      context,
+      container.helpers,
+      container.partials,
+      options.data || data,
+      blockParams && [options.blockParams].concat(blockParams),
+      currentDepths
+    );
  }
+
+  prog = executeDecorators(fn, prog, container, depths, data, blockParams);
+
  prog.program = i;
  prog.depth = depths ? depths.length : 0;
  prog.blockParams = declaredBlockParams || 0;
  return prog;
 }

+/**
+ * This is currently part of the official API, therefore implementation details should not be changed.
+ */
 export function resolvePartial(partial, context, options) {
  if (!partial) {
-    partial = options.partials[options.name];
+    if (options.name === '@partial-block') {
+      partial = options.data['partial-block'];
+    } else {
+      partial = options.partials[options.name];
+    }
  } else if (!partial.call && !options.name) {
    // This is a dynamic partial that returned a string
    options.name = partial;
@@ -194,7 +368,36 @@ export function resolvePartial(partial, context, options) {
 }

 export function invokePartial(partial, context, options) {
+  // Use the current closure context to save the partial-block if this partial
+  const currentPartialBlock = options.data && options.data['partial-block'];
  options.partial = true;
+  if (options.ids) {
+    options.data.contextPath = options.ids[0] || options.data.contextPath;
+  }
+
+  let partialBlock;
+  if (options.fn && options.fn !== noop) {
+    options.data = createFrame(options.data);
+    // Wrapper function to get access to currentPartialBlock from the closure
+    let fn = options.fn;
+    partialBlock = options.data['partial-block'] = function partialBlockWrapper(
+      context,
+      options = {}
+    ) {
+      // Restore the partial-block from the closure for the execution of the block
+      // i.e. the part inside the block of the partial call.
+      options.data = createFrame(options.data);
+      options.data['partial-block'] = currentPartialBlock;
+      return fn(context, options);
+    };
+    if (fn.partials) {
+      options.partials = Utils.extend({}, options.partials, fn.partials);
+    }
+  }
+
+  if (partial === undefined && partialBlock) {
+    partial = partialBlock;
+  }

  if (partial === undefined) {
    throw new Exception('The partial ' + options.name + ' could not be found');
@@ -203,7 +406,9 @@ export function invokePartial(partial, context, options) {
  }
 }

-export function noop() { return ''; }
+export function noop() {
+  return '';
+}

 function initData(context, data) {
  if (!data || !('root' in data)) {
@@ -212,3 +417,34 @@ function initData(context, data) {
  }
  return data;
 }
+
+function executeDecorators(fn, prog, container, depths, data, blockParams) {
+  if (fn.decorator) {
+    let props = {};
+    prog = fn.decorator(
+      prog,
+      props,
+      container,
+      depths && depths[0],
+      data,
+      blockParams,
+      depths
+    );
+    Utils.extend(prog, props);
+  }
+  return prog;
+}
+
+function wrapHelpersToPassLookupProperty(mergedHelpers, container) {
+  Object.keys(mergedHelpers).forEach(helperName => {
+    let helper = mergedHelpers[helperName];
+    mergedHelpers[helperName] = passLookupPropertyOption(helper, container);
+  });
+}
+
+function passLookupPropertyOption(helper, container) {
+  const lookupProperty = container.lookupProperty;
+  return wrapHelper(helper, options => {
+    return Utils.extend({ lookupProperty }, options);
+  });
+}
@@ -4,11 +4,12 @@ const escape = {
  '>': '&gt;',
  '"': '&quot;',
  "'": '&#x27;',
-  '`': '&#x60;'
+  '`': '&#x60;',
+  '=': '&#x3D;'
 };

-const badChars = /[&<>"'`]/g,
-      possible = /[&<>"'`]/;
+const badChars = /[&<>"'`=]/g,
+  possible = /[&<>"'`=]/;

 function escapeChar(chr) {
  return escape[chr];
@@ -30,24 +31,31 @@ export let toString = Object.prototype.toString;

 // Sourced from lodash
 // https://github.com/bestiejs/lodash/blob/master/LICENSE.txt
-/*eslint-disable func-style, no-var */
-var isFunction = function(value) {
+/* eslint-disable func-style */
+let isFunction = function(value) {
  return typeof value === 'function';
 };
 // fallback for older versions of Chrome and Safari
 /* istanbul ignore next */
 if (isFunction(/x/)) {
  isFunction = function(value) {
-    return typeof value === 'function' && toString.call(value) === '[object Function]';
+    return (
+      typeof value === 'function' &&
+      toString.call(value) === '[object Function]'
+    );
  };
 }
-export var isFunction;
-/*eslint-enable func-style, no-var */
+export { isFunction };
+/* eslint-enable func-style */

 /* istanbul ignore next */
-export const isArray = Array.isArray || function(value) {
-  return (value && typeof value === 'object') ? toString.call(value) === '[object Array]' : false;
-};
+export const isArray =
+  Array.isArray ||
+  function(value) {
+    return value && typeof value === 'object'
+      ? toString.call(value) === '[object Array]'
+      : false;
+  };

 // Older IE versions do not directly support indexOf so we must implement our own, sadly.
 export function indexOf(array, value) {
@@ -59,7 +67,6 @@ export function indexOf(array, value) {
  return -1;
 }

-
 export function escapeExpression(string) {
  if (typeof string !== 'string') {
    // don't escape SafeStrings, since they're already safe
@@ -77,7 +84,9 @@ export function escapeExpression(string) {
    string = '' + string;
  }

-  if (!possible.test(string)) { return string; }
+  if (!possible.test(string)) {
+    return string;
+  }
  return string.replace(badChars, escapeChar);
 }

@@ -91,6 +100,12 @@ export function isEmpty(value) {
  }
 }

+export function createFrame(object) {
+  let frame = extend({}, object);
+  frame._parent = object;
+  return frame;
+}
+
 export function blockParams(params, ids) {
  params.path = ids;
  return params;
@@ -1,9 +1,153 @@
-/*eslint-disable no-console */
+/* eslint-disable no-console */
+import Async from 'neo-async';
 import fs from 'fs';
 import * as Handlebars from './handlebars';
-import {basename} from 'path';
-import {SourceMapConsumer, SourceNode} from 'source-map';
-import uglify from 'uglify-js';
+import { basename } from 'path';
+import { SourceMapConsumer, SourceNode } from 'source-map';
+
+module.exports.loadTemplates = function(opts, callback) {
+  loadStrings(opts, function(err, strings) {
+    if (err) {
+      callback(err);
+    } else {
+      loadFiles(opts, function(err, files) {
+        if (err) {
+          callback(err);
+        } else {
+          opts.templates = strings.concat(files);
+          callback(undefined, opts);
+        }
+      });
+    }
+  });
+};
+
+function loadStrings(opts, callback) {
+  let strings = arrayCast(opts.string),
+    names = arrayCast(opts.name);
+
+  if (names.length !== strings.length && strings.length > 1) {
+    return callback(
+      new Handlebars.Exception(
+        'Number of names did not match the number of string inputs'
+      )
+    );
+  }
+
+  Async.map(
+    strings,
+    function(string, callback) {
+      if (string !== '-') {
+        callback(undefined, string);
+      } else {
+        // Load from stdin
+        let buffer = '';
+        process.stdin.setEncoding('utf8');
+
+        process.stdin.on('data', function(chunk) {
+          buffer += chunk;
+        });
+        process.stdin.on('end', function() {
+          callback(undefined, buffer);
+        });
+      }
+    },
+    function(err, strings) {
+      strings = strings.map((string, index) => ({
+        name: names[index],
+        path: names[index],
+        source: string
+      }));
+      callback(err, strings);
+    }
+  );
+}
+
+function loadFiles(opts, callback) {
+  // Build file extension pattern
+  let extension = (opts.extension || 'handlebars').replace(
+    /[\\^$*+?.():=!|{}\-[\]]/g,
+    function(arg) {
+      return '\\' + arg;
+    }
+  );
+  extension = new RegExp('\\.' + extension + '$');
+
+  let ret = [],
+    queue = (opts.files || []).map(template => ({ template, root: opts.root }));
+  Async.whilst(
+    () => queue.length,
+    function(callback) {
+      let { template: path, root } = queue.shift();
+
+      fs.stat(path, function(err, stat) {
+        if (err) {
+          return callback(
+            new Handlebars.Exception(`Unable to open template file "${path}"`)
+          );
+        }
+
+        if (stat.isDirectory()) {
+          opts.hasDirectory = true;
+
+          fs.readdir(path, function(err, children) {
+            /* istanbul ignore next : Race condition that being too lazy to test */
+            if (err) {
+              return callback(err);
+            }
+            children.forEach(function(file) {
+              let childPath = path + '/' + file;
+
+              if (
+                extension.test(childPath) ||
+                fs.statSync(childPath).isDirectory()
+              ) {
+                queue.push({ template: childPath, root: root || path });
+              }
+            });
+
+            callback();
+          });
+        } else {
+          fs.readFile(path, 'utf8', function(err, data) {
+            /* istanbul ignore next : Race condition that being too lazy to test */
+            if (err) {
+              return callback(err);
+            }
+
+            if (opts.bom && data.indexOf('\uFEFF') === 0) {
+              data = data.substring(1);
+            }
+
+            // Clean the template name
+            let name = path;
+            if (!root) {
+              name = basename(name);
+            } else if (name.indexOf(root) === 0) {
+              name = name.substring(root.length + 1);
+            }
+            name = name.replace(extension, '');
+
+            ret.push({
+              path: path,
+              name: name,
+              source: data
+            });
+
+            callback();
+          });
+        }
+      });
+    },
+    function(err) {
+      if (err) {
+        callback(err);
+      } else {
+        callback(undefined, ret);
+      }
+    }
+  );
+}

 module.exports.cli = function(opts) {
  if (opts.version) {
@@ -11,23 +155,31 @@ module.exports.cli = function(opts) {
    return;
  }

-  if (!opts.templates.length) {
-    throw new Handlebars.Exception('Must define at least one template or directory.');
+  if (!opts.templates.length && !opts.hasDirectory) {
+    throw new Handlebars.Exception(
+      'Must define at least one template or directory.'
+    );
  }

-  opts.templates.forEach(function(template) {
-    try {
-      fs.statSync(template);
-    } catch (err) {
-      throw new Handlebars.Exception(`Unable to open template file "${template}"`);
-    }
-  });
-
  if (opts.simple && opts.min) {
    throw new Handlebars.Exception('Unable to minimize simple output');
  }
-  if (opts.simple && (opts.templates.length !== 1 || fs.statSync(opts.templates[0]).isDirectory())) {
-    throw new Handlebars.Exception('Unable to output multiple templates in simple mode');
+
+  const multiple = opts.templates.length !== 1 || opts.hasDirectory;
+  if (opts.simple && multiple) {
+    throw new Handlebars.Exception(
+      'Unable to output multiple templates in simple mode'
+    );
+  }
+
+  // Force simple mode if we have only one template and it's unnamed.
+  if (
+    !opts.amd &&
+    !opts.commonjs &&
+    opts.templates.length === 1 &&
+    !opts.templates[0].name
+  ) {
+    opts.simple = true;
  }

  // Convert the known list into a hash
@@ -41,14 +193,16 @@ module.exports.cli = function(opts) {
    }
  }

-  // Build file extension pattern
-  let extension = opts.extension.replace(/[\\^$*+?.():=!|{}\-\[\]]/g, function(arg) { return '\\' + arg; });
-  extension = new RegExp('\\.' + extension + '$');
+  const objectName = opts.partial ? 'Handlebars.partials' : 'templates';

  let output = new SourceNode();
  if (!opts.simple) {
    if (opts.amd) {
-      output.add('define([\'' + opts.handlebarPath + 'handlebars.runtime\'], function(Handlebars) {\n  Handlebars = Handlebars["default"];');
+      output.add(
+        "define(['" +
+          opts.handlebarPath +
+          'handlebars.runtime\'], function(Handlebars) {\n  Handlebars = Handlebars["default"];'
+      );
    } else if (opts.commonjs) {
      output.add('var Handlebars = require("' + opts.commonjs + '");');
    } else {
@@ -63,81 +217,57 @@ module.exports.cli = function(opts) {
    }
    output.add('{};\n');
  }
-  function processTemplate(template, root) {
-    let path = template,
-        stat = fs.statSync(path);
-    if (stat.isDirectory()) {
-      fs.readdirSync(template).map(function(file) {
-        let childPath = template + '/' + file;
-
-        if (extension.test(childPath) || fs.statSync(childPath).isDirectory()) {
-          processTemplate(childPath, root || template);
-        }
-      });
-    } else {
-      let data = fs.readFileSync(path, 'utf8');
-
-      if (opts.bom && data.indexOf('\uFEFF') === 0) {
-        data = data.substring(1);
-      }
-
-      let options = {
-        knownHelpers: known,
-        knownHelpersOnly: opts.o
-      };
-
-      if (opts.map) {
-        options.srcName = path;
-      }
-      if (opts.data) {
-        options.data = true;
-      }
-
-      // Clean the template name
-      if (!root) {
-        template = basename(template);
-      } else if (template.indexOf(root) === 0) {
-        template = template.substring(root.length + 1);
-      }
-      template = template.replace(extension, '');
-
-      let precompiled = Handlebars.precompile(data, options);
-
-      // If we are generating a source map, we have to reconstruct the SourceNode object
-      if (opts.map) {
-        let consumer = new SourceMapConsumer(precompiled.map);
-        precompiled = SourceNode.fromStringWithSourceMap(precompiled.code, consumer);
-      }
-
-      if (opts.simple) {
-        output.add([precompiled, '\n']);
-      } else if (opts.partial) {
-        if (opts.amd && (opts.templates.length == 1 && !fs.statSync(opts.templates[0]).isDirectory())) {
-          output.add('return ');
-        }
-        output.add(['Handlebars.partials[\'', template, '\'] = template(', precompiled, ');\n']);
-      } else {
-        if (opts.amd && (opts.templates.length == 1 && !fs.statSync(opts.templates[0]).isDirectory())) {
-          output.add('return ');
-        }
-        output.add(['templates[\'', template, '\'] = template(', precompiled, ');\n']);
-      }
-    }
-  }

  opts.templates.forEach(function(template) {
-    processTemplate(template, opts.root);
+    let options = {
+      knownHelpers: known,
+      knownHelpersOnly: opts.o
+    };
+
+    if (opts.map) {
+      options.srcName = template.path;
+    }
+    if (opts.data) {
+      options.data = true;
+    }
+
+    let precompiled = Handlebars.precompile(template.source, options);
+
+    // If we are generating a source map, we have to reconstruct the SourceNode object
+    if (opts.map) {
+      let consumer = new SourceMapConsumer(precompiled.map);
+      precompiled = SourceNode.fromStringWithSourceMap(
+        precompiled.code,
+        consumer
+      );
+    }
+
+    if (opts.simple) {
+      output.add([precompiled, '\n']);
+    } else {
+      if (!template.name) {
+        throw new Handlebars.Exception('Name missing for template');
+      }
+
+      if (opts.amd && !multiple) {
+        output.add('return ');
+      }
+      output.add([
+        objectName,
+        "['",
+        template.name,
+        "'] = template(",
+        precompiled,
+        ');\n'
+      ]);
+    }
  });

  // Output the content
  if (!opts.simple) {
    if (opts.amd) {
-      if (opts.templates.length > 1 || (opts.templates.length == 1 && fs.statSync(opts.templates[0]).isDirectory())) {
-        if (opts.partial) {
-          output.add('return Handlebars.partials;\n');
-        } else {
-          output.add('return templates;\n');
-        }
+      if (multiple) {
+        output.add(['return ', objectName, ';\n']);
      }
      output.add('});');
    } else if (!opts.commonjs) {
@@ -145,7 +275,6 @@ module.exports.cli = function(opts) {
    }
  }

-
  if (opts.map) {
    output.add('\n//# sourceMappingURL=' + opts.map + '\n');
  }
@@ -154,15 +283,7 @@ module.exports.cli = function(opts) {
  output.map = output.map + '';

  if (opts.min) {
-    output = uglify.minify(output.code, {
-      fromString: true,
-
-      outSourceMap: opts.map,
-      inSourceMap: JSON.parse(output.map)
-    });
-    if (opts.map) {
-      output.code += '\n//# sourceMappingURL=' + opts.map + '\n';
-    }
+    output = minify(output, opts.map);
  }

  if (opts.map) {
@@ -176,3 +297,44 @@ module.exports.cli = function(opts) {
    console.log(output);
  }
 };
+
+function arrayCast(value) {
+  value = value != null ? value : [];
+  if (!Array.isArray(value)) {
+    value = [value];
+  }
+  return value;
+}
+
+/**
+ * Run uglify to minify the compiled template, if uglify exists in the dependencies.
+ *
+ * We are using `require` instead of `import` here, because es6-modules do not allow
+ * dynamic imports and uglify-js is an optional dependency. Since we are inside NodeJS here, this
+ * should not be a problem.
+ *
+ * @param {string} output the compiled template
+ * @param {string} sourceMapFile the file to write the source map to.
+ */
+function minify(output, sourceMapFile) {
+  try {
+    // Try to resolve uglify-js in order to see if it does exist
+    require.resolve('uglify-js');
+  } catch (e) {
+    if (e.code !== 'MODULE_NOT_FOUND') {
+      // Something else seems to be wrong
+      throw e;
+    }
+    // it does not exist!
+    console.error(
+      'Code minimization is disabled due to missing uglify-js dependency'
+    );
+    return output;
+  }
+  return require('uglify-js').minify(output.code, {
+    sourceMap: {
+      content: output.map,
+      url: sourceMapFile
+    }
+  });
+}
@@ -0,0 +1,9 @@
+module.exports = {
+  'check-coverage': true,
+  branches: 100,
+  lines: 100,
+  functions: 100,
+  statements: 100,
+  exclude: ['**/spec/**', '**/handlebars/compiler/parser.js'],
+  reporter: 'html'
+};
--- a/Show More
+++ b/Show More