Fix a number of outstanding issues:

* {{}} escape their contents, {{{}}} and {{& }} do not
* Add support in the parser, tokenizer and AST for partials
  with context (support is still not there in the runtime)
* Fix some inconsistencies with the old behavior involving
  the correct printing of null and undefined
* Add Handlebars.Exception
* Fixed an issue involving ./foo and this/foo
* Fleshed out helperMissing in the specs (this will be
  moved out into handlebars proper once registerHelper
  and registerPartial are added)

lib/handlebars.js

@@ -6,6 +6,9 @@ if(exports) {
   Handlebars.PrintVisitor    = require("handlebars/printer").PrintVisitor;
   Handlebars.Parser          = require("handlebars/parser").parser;
   Handlebars.Runtime         = require("handlebars/runtime").Runtime;
+  Handlebars.Utils           = require("handlebars/utils").Utils;
+  Handlebars.SafeString      = require("handlebars/utils").SafeString;
+  Handlebars.Exception       = require("handlebars/utils").Exception;
 } else {
   Handlebars.Parser = handlebars;
 }

lib/handlebars/ast.js

@@ -8,15 +8,17 @@ Handlebars.AST.ProgramNode = function(statements, inverse) {
   this.inverse = inverse;
 };
 
-Handlebars.AST.MustacheNode = function(params) {
+Handlebars.AST.MustacheNode = function(params, unescaped) {
   this.type = "mustache";
   this.id = params[0];
   this.params = params.slice(1);
+  this.escaped = !unescaped;
 };
 
-Handlebars.AST.PartialNode = function(id) {
+Handlebars.AST.PartialNode = function(id, context) {
   this.type    = "partial";
   this.id      = id;
+  this.context = context;
 };
 
 Handlebars.AST.BlockNode = function(mustache, program) {
@@ -39,7 +41,7 @@ Handlebars.AST.IdNode = function(parts) {
     var part = parts[i];
 
     if(part === "..") { depth++; }
-    else if(part === "." || part === "this") { break; }
+    else if(part === "." || part === "this") { continue; }
     else { dig.push(part) }
   }
 

lib/handlebars/handlebars_lexer.js

@@ -96,7 +96,10 @@ Handlebars.HandlebarsLexer.prototype.lex = function() {
       return "OPEN_ENDBLOCK";
     } else if(peek === "^") {
       this.getchar();
-      return "OPEN_INVERSE"
+      return "OPEN_INVERSE";
+    } else if(peek === "{" || peek === "&") {
+      this.getchar();
+      return "OPEN_UNESCAPED";
     } else if(peek === "!") {
       this.readchar();
       this.setupLex(); // reset the lexer state so the yytext is the comment only

lib/handlebars/printer.js

@@ -71,7 +71,9 @@ Handlebars.PrintVisitor.prototype.mustache = function(mustache) {
 };
 
 Handlebars.PrintVisitor.prototype.partial = function(partial) {
-  return this.pad("{{> " + this.accept(partial.id) + " }}");
+  var content = this.accept(partial.id);
+  if(partial.context) { content = content + " " + this.accept(partial.context); }
+  return this.pad("{{> " + content + " }}");
 };
 
 Handlebars.PrintVisitor.prototype.STRING = function(string) {

lib/handlebars/runtime.js

@@ -70,7 +70,7 @@ Handlebars.Runtime = function(context, fallback, stack) {
 
   var newContext = this.context = new Handlebars.Context;
 
-  if(context.isContext) {
+  if(context && context.isContext) {
     newContext.data     = context.data;
     newContext.fallback = context.fallback;
   } else {
@@ -103,17 +103,22 @@ Handlebars.Runtime.prototype = {
   mustache: function(mustache) {
     var idObj  = this.accept(mustache.id);
     var params = mustache.params;
+    var buf;
 
     for(var i=0, l=params.length; i<l; i++) {
       params[i] = this.accept(params[i]).data;
     }
 
     if(toString.call(idObj.data) === "[object Function]") {
-      this.buffer = this.buffer + idObj.data.apply(this.wrapContext(), params);
+      buf = idObj.data.apply(this.wrapContext(), params);
     } else {
       if(params.length) { throw new Error(mustache.id.parts.join("/") + " is not a Function, so you cannot have Function parameters"); }
-      this.buffer = this.buffer + idObj.data;
+      buf = idObj.data;
     }
+
+    if(buf && mustache.escaped) { buf = Handlebars.Utils.escapeExpression(buf); }
+
+    this.buffer = this.buffer + (buf == null ? '' : buf);
   },
 
   block: function(block) {

lib/handlebars/utils.js

@@ -0,0 +1,54 @@
+if(exports) {
+  var Handlebars = {};
+}
+
+Handlebars.Exception = function(message) {
+  this.message = message;
+};
+
+// Build out our basic SafeString type
+Handlebars.SafeString = function(string) {
+  this.string = string;
+}
+Handlebars.SafeString.prototype.toString = function() {
+  return this.string.toString();
+}
+
+Handlebars.Utils = {
+  escapeExpression: function(string) {
+    // don't escape SafeStrings, since they're already safe
+    if (string instanceof Handlebars.SafeString) {
+      return string.toString();
+    }
+    else if (string === null) {
+      string = "";
+    }
+
+    return string.toString().replace(/&(?!\w+;)|["\\<>]/g, function(str) {
+      switch(str) {
+        case "&":
+          return "&amp;";
+          break;
+        case '"':
+          return "\"";
+        case "\\":
+          return "\\\\";
+          break;
+        case "<":
+          return "&lt;";
+          break;
+        case ">":
+          return "&gt;";
+          break;
+        default:
+          return str;
+      }
+    });
+  }
+}
+
+if(exports) {
+  exports.Utils = Handlebars.Utils;
+  exports.SafeString = Handlebars.SafeString;
+  exports.Exception = Handlebars.Exception;
+}

spec/parser_spec.rb

@@ -64,8 +64,10 @@ describe "Parser" do
       pad("{{ #{id} [#{params.join(", ")}] }}")
     end
 
-    def partial(id)
+    def partial(id, context = nil)
-      pad("{{> #{id} }}")
+      content = id.dup
+      content << " #{context}" if context
+      pad("{{> #{content} }}")
     end
 
     def comment(comment)
@@ -97,6 +99,10 @@ describe "Parser" do
     ast_for("{{foo/bar}}").should == program { mustache path("foo", "bar") }
   end
 
+  it "parses mustaches with this/foo" do
+    ast_for("{{this/foo}}").should == program { mustache id("foo") }
+  end
+
   it "parses mustaches with parameters" do
     ast_for("{{foo bar}}").should == program { mustache id("foo"), id("bar") }
   end
@@ -116,6 +122,10 @@ describe "Parser" do
     ast_for("{{> foo }}").should == program { partial id("foo") }
   end
 
+  it "parses a partial with context" do
+    ast_for("{{> foo bar}}").should == program { partial id("foo"), id("bar") }
+  end
+
   it "parses a comment" do
     ast_for("{{! this is a comment }}").should == program do
       comment " this is a comment "

spec/qunit_spec.js

@@ -1,10 +1,19 @@
 module("basic context");
 
 var helperMissing = function(context, fn) {
+  var ret = "";
+
   if(context === true) {
     return fn(this);
   } else if(context === false) {
     return "";
+  } else if(Object.prototype.toString.call(context) === "[object Array]") {
+    for(var i=0, j=context.length; i<j; i++) {
+      ret = ret + fn(context[i]);
+    }
+    return ret;
+  } else {
+		return fn(context);
 	}
 }
 

spec/spec_helper.rb

@@ -40,6 +40,7 @@ module Handlebars
       context.load('lib/handlebars/printer.js')
       context.load('lib/handlebars/parser.js')
       context.load('lib/handlebars/runtime.js')
+      context.load('lib/handlebars/utils.js')
       context.load('lib/handlebars.js')
     end
   end

spec/tokenizer_spec.rb

@@ -36,12 +36,19 @@ describe "Tokenizer" do
     result[1].should be_token("ID", "foo")
   end
 
-  it "tokenizes a path as 'OPEN ID CLOSE'" do
+  it "tokenizes a path as 'OPEN (ID SEP)* ID CLOSE'" do
     result = tokenize("{{../foo/bar}}")
     result.should match_tokens(%w(OPEN ID SEP ID SEP ID CLOSE))
     result[1].should be_token("ID", "..")
   end
 
+  it "tokenizes a path with this/foo as OPEN ID SEP ID CLOSE" do
+    result = tokenize("{{this/foo}}")
+    result.should match_tokens(%w(OPEN ID SEP ID CLOSE))
+    result[1].should be_token("ID", "this")
+    result[3].should be_token("ID", "foo")
+  end
+
   it "tokenizes a simple mustahe with spaces as 'OPEN ID CLOSE'" do
     result = tokenize("{{  foo  }}")
     result.should match_tokens(%w(OPEN ID CLOSE))
@@ -60,6 +67,11 @@ describe "Tokenizer" do
     result.should match_tokens(%w(OPEN_PARTIAL ID CLOSE))
   end
 
+  it "tokenizes a partial with context as 'OPEN_PARTIAL ID ID CLOSE'" do
+    result = tokenize("{{> foo bar }}")
+    result.should match_tokens(%w(OPEN_PARTIAL ID ID CLOSE))
+  end
+
   it "tokenizes a partial without spaces as 'OPEN_PARTIAL ID CLOSE'" do
     result = tokenize("{{>foo}}")
     result.should match_tokens(%w(OPEN_PARTIAL ID CLOSE))

src/handlebars.yy

@@ -34,10 +34,13 @@ closeBlock
 
 mustache
   : OPEN inMustache CLOSE { $$ = new yy.MustacheNode($2) }
+  | OPEN_UNESCAPED inMustache CLOSE { $$ = new yy.MustacheNode($2, true) }
   ;
 
+
 partial
   : OPEN_PARTIAL path CLOSE { $$ = new yy.PartialNode($2) }
+  | OPEN_PARTIAL path path CLOSE { $$ = new yy.PartialNode($2, $3) }
   ;
 
 simpleInverse