From 3b0970d8aa969c79b19fa737dc990ce7c62699d2 Mon Sep 17 00:00:00 2001
From: wycats <wycats@gmail.com>
Date: Thu, 25 Nov 2010 23:32:32 -0800
Subject: [PATCH] Start working on the runtime

---
 lib/handlebars.js         |   1 +
 lib/handlebars/runtime.js | 120 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 121 insertions(+)
 create mode 100644 lib/handlebars/runtime.js

diff --git a/lib/handlebars.js b/lib/handlebars.js
index f7094752..ca080cad 100644
--- a/lib/handlebars.js
+++ b/lib/handlebars.js
@@ -5,6 +5,7 @@ if(exports) {
   Handlebars.HandlebarsLexer = require("handlebars/handlebars_lexer").Lexer;
   Handlebars.PrintVisitor    = require("handlebars/printer").PrintVisitor;
   Handlebars.Parser          = require("handlebars/parser").parser;
+  Handlebars.Runtime         = require("handlebars/runtime").Runtime;
 } else {
   Handlebars.Parser = handlebars;
 }
diff --git a/lib/handlebars/runtime.js b/lib/handlebars/runtime.js
new file mode 100644
index 00000000..80defd8e
--- /dev/null
+++ b/lib/handlebars/runtime.js
@@ -0,0 +1,120 @@
+if(exports) {
+  var inspect = function(obj) {
+    require("sys").print(require("sys").inspect(obj) + "\n");
+  }
+  var Handlebars = {};
+  Handlebars.AST = require("handlebars/ast");
+  Handlebars.Visitor = require("handlebars/jison_ext").Visitor;
+}
+
+Handlebars.Context = function(data, fallback) {
+  this.data     = data;
+  this.fallback = fallback;
+};
+
+Handlebars.Context.prototype = {
+  isContext: true,
+
+  clone: function() {
+    var context = new Handlebars.Context;
+    context.data = this.data;
+    context.fallback = this.fallback;
+    return context;
+  },
+
+  evaluate: function(path, stack) {
+    var context = this.clone();
+    var depth = path.depth, dig = path.dig, parts = path.parts;
+
+    if(depth > stack.length) { context.data = null; }
+    else if(depth > 0) { context = stack[stack.length - depth].clone(); }
+
+    for(var i=0,l=parts.length; i<l && context.data != null; i++) {
+      context.data = context.data[parts[i]];
+    }
+
+    if(parts.length === 1 && context.data === undefined) {
+      context.data = context.fallback[parts[0]];
+    }
+
+    return context;
+  }
+};
+
+Handlebars.K = function() { return this; };
+
+Handlebars.proxy = function(obj) {
+  var Proxy = this.K;
+  Proxy.prototype = obj;
+  return new Proxy;
+}
+
+Handlebars.Runtime = function(context, fallback, stack) {
+  this.stack = stack || [];
+  this.buffer = "";
+
+  var newContext = this.context = new Handlebars.Context;
+
+  if(context.isContext) {
+    newContext.data     = context.data;
+    newContext.fallback = context.fallback;
+  } else {
+    newContext.data     = context;
+    newContext.fallback = fallback || {};
+  }
+};
+
+Handlebars.Runtime.prototype = {
+  accept: Handlebars.Visitor.prototype.accept,
+
+  ID: function(path) {
+    return this.context.evaluate(path, this.stack);
+  },
+
+  STRING: function(string) {
+    return { data: string.string };
+  },
+
+  program: function(program) {
+    var statements = program.statements;
+
+    for(var i=0, l=statements.length; i<l; i++) {
+      this.accept(statements[i]);
+    }
+  },
+
+  mustache: function(mustache) {
+    var idObj  = this.accept(mustache.id);
+    var params = mustache.params;
+
+    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);
+    } 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;
+    }
+  },
+
+  content: function(content) {
+    this.buffer += content.string;
+  },
+
+  wrapContext: function() {
+    var proxy     = Handlebars.proxy(this.context.data);
+    var context   = proxy.__context__ = this.context;
+    var stack     = proxy.__stack__   = this.stack.slice(0);
+
+    proxy.__get__ = function(path) {
+      return context.evaluate(path, stack).data
+    };
+  }
+
+}
+
+if(exports) {
+  exports.Runtime = Handlebars.Runtime;
+}