diff --git a/.jshintrc b/.jshintrc
index ecd80acfc..bb29c76e8 100644
--- a/.jshintrc
+++ b/.jshintrc
@@ -35,7 +35,7 @@
     "evil": true,
     "forin": false,
     "immed": false,
-    "laxbreak": false,
+    "laxbreak": true,
     "newcap": true,
     "noarg": true,
     "noempty": false,
diff --git a/bench/templates/subexpression.js b/bench/templates/subexpression.js
new file mode 100644
index 000000000..261c22d01
--- /dev/null
+++ b/bench/templates/subexpression.js
@@ -0,0 +1,14 @@
+module.exports = {
+  helpers: {
+    echo: function(value) {
+      return 'foo ' + value;
+    },
+    header: function() {
+      return "Colors";
+    }
+  },
+  handlebars: "{{echo (header)}}",
+  eco: "<%= @echo(@header()) %>"
+};
+
+module.exports.context = module.exports.helpers;
diff --git a/components/bower.json b/components/bower.json
index b55ebc502..25923a475 100644
--- a/components/bower.json
+++ b/components/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "handlebars",
-  "version": "1.2.1",
+  "version": "1.3.0",
   "main": "handlebars.js",
   "dependencies": {}
 }
diff --git a/components/handlebars.js.nuspec b/components/handlebars.js.nuspec
index 610ca2f31..e4a169103 100644
--- a/components/handlebars.js.nuspec
+++ b/components/handlebars.js.nuspec
@@ -2,7 +2,7 @@
 <package>
 	<metadata>
 		<id>handlebars.js</id>
-		<version>1.2.1</version>
+		<version>1.3.0</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>
diff --git a/lib/handlebars.js b/lib/handlebars.js
index c8956b401..ffa9c7ab2 100644
--- a/lib/handlebars.js
+++ b/lib/handlebars.js
@@ -14,7 +14,9 @@ var create = function() {
   hb.compile = function(input, options) {
     return compile(input, options, hb);
   };
-  hb.precompile = precompile;
+  hb.precompile = function (input, options) {
+    return precompile(input, options, hb);
+  };
 
   hb.AST = AST;
   hb.Compiler = Compiler;
diff --git a/lib/handlebars/base.js b/lib/handlebars/base.js
index 027f05254..00c8bf1ff 100644
--- a/lib/handlebars/base.js
+++ b/lib/handlebars/base.js
@@ -1,7 +1,7 @@
 module Utils from "./utils";
 import Exception from "./exception";
 
-export var VERSION = "1.2.1";
+export var VERSION = "1.3.0";
 export var COMPILER_REVISION = 4;
 
 export var REVISION_CHANGES = {
@@ -53,7 +53,7 @@ function registerDefaultHelpers(instance) {
     if(arguments.length === 2) {
       return undefined;
     } else {
-      throw new Error("Missing helper: '" + arg + "'");
+      throw new Exception("Missing helper: '" + arg + "'");
     }
   });
 
diff --git a/lib/handlebars/compiler/ast.js b/lib/handlebars/compiler/ast.js
index 64cd3b7d2..002fd3be6 100644
--- a/lib/handlebars/compiler/ast.js
+++ b/lib/handlebars/compiler/ast.js
@@ -1,22 +1,51 @@
 import Exception from "../exception";
 
+function LocationInfo(locInfo){
+  locInfo = locInfo || {};
+  this.firstLine   = locInfo.first_line;
+  this.firstColumn = locInfo.first_column;
+  this.lastColumn  = locInfo.last_column;
+  this.lastLine    = locInfo.last_line;
+}
+
 var AST = {
-  ProgramNode: function(statements, inverseStrip, inverse) {
+  ProgramNode: function(statements, inverseStrip, inverse, locInfo) {
+    var inverseLocationInfo, firstInverseNode;
+    if (arguments.length === 3) {
+      locInfo = inverse;
+      inverse = null;
+    } else if (arguments.length === 2) {
+      locInfo = inverseStrip;
+      inverseStrip = null;
+    }
+
+    LocationInfo.call(this, locInfo);
     this.type = "program";
     this.statements = statements;
     this.strip = {};
 
     if(inverse) {
-      this.inverse = new AST.ProgramNode(inverse, inverseStrip);
+      firstInverseNode = inverse[0];
+      if (firstInverseNode) {
+        inverseLocationInfo = {
+          first_line: firstInverseNode.firstLine,
+          last_line: firstInverseNode.lastLine,
+          last_column: firstInverseNode.lastColumn,
+          first_column: firstInverseNode.firstColumn
+        };
+        this.inverse = new AST.ProgramNode(inverse, inverseStrip, inverseLocationInfo);
+      } else {
+        this.inverse = new AST.ProgramNode(inverse, inverseStrip);
+      }
       this.strip.right = inverseStrip.left;
     } else if (inverseStrip) {
       this.strip.left = inverseStrip.right;
     }
   },
 
-  MustacheNode: function(rawParams, hash, open, strip) {
+  MustacheNode: function(rawParams, hash, open, strip, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "mustache";
-    this.hash = hash;
     this.strip = strip;
 
     // Open may be a string parsed from the parser or a passed boolean flag
@@ -28,6 +57,29 @@ var AST = {
       this.escaped = !!open;
     }
 
+    if (rawParams instanceof AST.SexprNode) {
+      this.sexpr = rawParams;
+    } else {
+      // Support old AST API
+      this.sexpr = new AST.SexprNode(rawParams, hash);
+    }
+
+    this.sexpr.isRoot = true;
+
+    // Support old AST API that stored this info in MustacheNode
+    this.id = this.sexpr.id;
+    this.params = this.sexpr.params;
+    this.hash = this.sexpr.hash;
+    this.eligibleHelper = this.sexpr.eligibleHelper;
+    this.isHelper = this.sexpr.isHelper;
+  },
+
+  SexprNode: function(rawParams, hash, locInfo) {
+    LocationInfo.call(this, locInfo);
+
+    this.type = "sexpr";
+    this.hash = hash;
+
     var id = this.id = rawParams[0];
     var params = this.params = rawParams.slice(1);
 
@@ -45,19 +97,22 @@ var AST = {
     // pass or at runtime.
   },
 
-  PartialNode: function(partialName, context, strip) {
+  PartialNode: function(partialName, context, strip, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type         = "partial";
     this.partialName  = partialName;
     this.context      = context;
     this.strip = strip;
   },
 
-  BlockNode: function(mustache, program, inverse, close) {
-    if(mustache.id.original !== close.path.original) {
-      throw new Exception(mustache.id.original + " doesn't match " + close.path.original);
+  BlockNode: function(mustache, program, inverse, close, locInfo) {
+    LocationInfo.call(this, locInfo);
+
+    if(mustache.sexpr.id.original !== close.path.original) {
+      throw new Exception(mustache.sexpr.id.original + " doesn't match " + close.path.original, this);
     }
 
-    this.type = "block";
+    this.type = 'block';
     this.mustache = mustache;
     this.program  = program;
     this.inverse  = inverse;
@@ -75,17 +130,20 @@ var AST = {
     }
   },
 
-  ContentNode: function(string) {
+  ContentNode: function(string, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "content";
     this.string = string;
   },
 
-  HashNode: function(pairs) {
+  HashNode: function(pairs, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "hash";
     this.pairs = pairs;
   },
 
-  IdNode: function(parts) {
+  IdNode: function(parts, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "ID";
 
     var original = "",
@@ -97,11 +155,16 @@ var AST = {
       original += (parts[i].separator || '') + part;
 
       if (part === ".." || part === "." || part === "this") {
-        if (dig.length > 0) { throw new Exception("Invalid path: " + original); }
-        else if (part === "..") { depth++; }
-        else { this.isScoped = true; }
+        if (dig.length > 0) {
+          throw new Exception("Invalid path: " + original, this);
+        } else if (part === "..") {
+          depth++;
+        } else {
+          this.isScoped = true;
+        }
+      } else {
+        dig.push(part);
       }
-      else { dig.push(part); }
     }
 
     this.original = original;
@@ -116,37 +179,43 @@ var AST = {
     this.stringModeValue = this.string;
   },
 
-  PartialNameNode: function(name) {
+  PartialNameNode: function(name, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "PARTIAL_NAME";
     this.name = name.original;
   },
 
-  DataNode: function(id) {
+  DataNode: function(id, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "DATA";
     this.id = id;
   },
 
-  StringNode: function(string) {
+  StringNode: function(string, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "STRING";
     this.original =
       this.string =
       this.stringModeValue = string;
   },
 
-  IntegerNode: function(integer) {
+  IntegerNode: function(integer, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "INTEGER";
     this.original =
       this.integer = integer;
     this.stringModeValue = Number(integer);
   },
 
-  BooleanNode: function(bool) {
+  BooleanNode: function(bool, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "BOOLEAN";
     this.bool = bool;
     this.stringModeValue = bool === "true";
   },
 
-  CommentNode: function(comment) {
+  CommentNode: function(comment, locInfo) {
+    LocationInfo.call(this, locInfo);
     this.type = "comment";
     this.comment = comment;
   }
diff --git a/lib/handlebars/compiler/compiler.js b/lib/handlebars/compiler/compiler.js
index daea3072c..461f98b65 100644
--- a/lib/handlebars/compiler/compiler.js
+++ b/lib/handlebars/compiler/compiler.js
@@ -1,7 +1,4 @@
 import Exception from "../exception";
-import { parse } from "./base";
-import JavaScriptCompiler from "./javascript-compiler";
-import AST from "./ast";
 
 export function Compiler() {}
 
@@ -159,12 +156,13 @@ Compiler.prototype = {
       inverse = this.compileProgram(inverse);
     }
 
-    var type = this.classifyMustache(mustache);
+    var sexpr = mustache.sexpr;
+    var type = this.classifySexpr(sexpr);
 
     if (type === "helper") {
-      this.helperMustache(mustache, program, inverse);
+      this.helperSexpr(sexpr, program, inverse);
     } else if (type === "simple") {
-      this.simpleMustache(mustache);
+      this.simpleSexpr(sexpr);
 
       // now that the simple mustache is resolved, we need to
       // evaluate it by executing `blockHelperMissing`
@@ -173,7 +171,7 @@ Compiler.prototype = {
       this.opcode('emptyHash');
       this.opcode('blockValue');
     } else {
-      this.ambiguousMustache(mustache, program, inverse);
+      this.ambiguousSexpr(sexpr, program, inverse);
 
       // now that the simple mustache is resolved, we need to
       // evaluate it by executing `blockHelperMissing`
@@ -201,6 +199,12 @@ Compiler.prototype = {
         }
         this.opcode('getContext', val.depth || 0);
         this.opcode('pushStringParam', val.stringModeValue, val.type);
+
+        if (val.type === 'sexpr') {
+          // Subexpressions get evaluated and passed in
+          // in string params mode.
+          this.sexpr(val);
+        }
       } else {
         this.accept(val);
       }
@@ -229,26 +233,17 @@ Compiler.prototype = {
   },
 
   mustache: function(mustache) {
-    var options = this.options;
-    var type = this.classifyMustache(mustache);
-
-    if (type === "simple") {
-      this.simpleMustache(mustache);
-    } else if (type === "helper") {
-      this.helperMustache(mustache);
-    } else {
-      this.ambiguousMustache(mustache);
-    }
+    this.sexpr(mustache.sexpr);
 
-    if(mustache.escaped && !options.noEscape) {
+    if(mustache.escaped && !this.options.noEscape) {
       this.opcode('appendEscaped');
     } else {
       this.opcode('append');
     }
   },
 
-  ambiguousMustache: function(mustache, program, inverse) {
-    var id = mustache.id,
+  ambiguousSexpr: function(sexpr, program, inverse) {
+    var id = sexpr.id,
         name = id.parts[0],
         isBlock = program != null || inverse != null;
 
@@ -260,8 +255,8 @@ Compiler.prototype = {
     this.opcode('invokeAmbiguous', name, isBlock);
   },
 
-  simpleMustache: function(mustache) {
-    var id = mustache.id;
+  simpleSexpr: function(sexpr) {
+    var id = sexpr.id;
 
     if (id.type === 'DATA') {
       this.DATA(id);
@@ -277,16 +272,28 @@ Compiler.prototype = {
     this.opcode('resolvePossibleLambda');
   },
 
-  helperMustache: function(mustache, program, inverse) {
-    var params = this.setupFullMustacheParams(mustache, program, inverse),
-        name = mustache.id.parts[0];
+  helperSexpr: function(sexpr, program, inverse) {
+    var params = this.setupFullMustacheParams(sexpr, program, inverse),
+        name = sexpr.id.parts[0];
 
     if (this.options.knownHelpers[name]) {
       this.opcode('invokeKnownHelper', params.length, name);
     } else if (this.options.knownHelpersOnly) {
-      throw new Error("You specified knownHelpersOnly, but used the unknown helper " + name);
+      throw new Exception("You specified knownHelpersOnly, but used the unknown helper " + name, sexpr);
     } else {
-      this.opcode('invokeHelper', params.length, name);
+      this.opcode('invokeHelper', params.length, name, sexpr.isRoot);
+    }
+  },
+
+  sexpr: function(sexpr) {
+    var type = this.classifySexpr(sexpr);
+
+    if (type === "simple") {
+      this.simpleSexpr(sexpr);
+    } else if (type === "helper") {
+      this.helperSexpr(sexpr);
+    } else {
+      this.ambiguousSexpr(sexpr);
     }
   },
 
@@ -309,7 +316,7 @@ Compiler.prototype = {
   DATA: function(data) {
     this.options.data = true;
     if (data.id.isScoped || data.id.depth) {
-      throw new Exception('Scoped data references are not supported: ' + data.original);
+      throw new Exception('Scoped data references are not supported: ' + data.original, data);
     }
 
     this.opcode('lookupData');
@@ -343,7 +350,6 @@ Compiler.prototype = {
   },
 
   addDepth: function(depth) {
-    if(isNaN(depth)) { throw new Error("EWOT"); }
     if(depth === 0) { return; }
 
     if(!this.depths[depth]) {
@@ -352,14 +358,14 @@ Compiler.prototype = {
     }
   },
 
-  classifyMustache: function(mustache) {
-    var isHelper   = mustache.isHelper;
-    var isEligible = mustache.eligibleHelper;
+  classifySexpr: function(sexpr) {
+    var isHelper   = sexpr.isHelper;
+    var isEligible = sexpr.eligibleHelper;
     var options    = this.options;
 
     // if ambiguous, we can possibly resolve the ambiguity now
     if (isEligible && !isHelper) {
-      var name = mustache.id.parts[0];
+      var name = sexpr.id.parts[0];
 
       if (options.knownHelpers[name]) {
         isHelper = true;
@@ -386,35 +392,27 @@ Compiler.prototype = {
 
         this.opcode('getContext', param.depth || 0);
         this.opcode('pushStringParam', param.stringModeValue, param.type);
+
+        if (param.type === 'sexpr') {
+          // Subexpressions get evaluated and passed in
+          // in string params mode.
+          this.sexpr(param);
+        }
       } else {
         this[param.type](param);
       }
     }
   },
 
-  setupMustacheParams: function(mustache) {
-    var params = mustache.params;
-    this.pushParams(params);
-
-    if(mustache.hash) {
-      this.hash(mustache.hash);
-    } else {
-      this.opcode('emptyHash');
-    }
-
-    return params;
-  },
-
-  // this will replace setupMustacheParams when we're done
-  setupFullMustacheParams: function(mustache, program, inverse) {
-    var params = mustache.params;
+  setupFullMustacheParams: function(sexpr, program, inverse) {
+    var params = sexpr.params;
     this.pushParams(params);
 
     this.opcode('pushProgram', program);
     this.opcode('pushProgram', inverse);
 
-    if(mustache.hash) {
-      this.hash(mustache.hash);
+    if (sexpr.hash) {
+      this.hash(sexpr.hash);
     } else {
       this.opcode('emptyHash');
     }
@@ -423,8 +421,8 @@ Compiler.prototype = {
   }
 };
 
-export function precompile(input, options) {
-  if (input == null || (typeof input !== 'string' && input.constructor !== AST.ProgramNode)) {
+export function precompile(input, options, env) {
+  if (input == null || (typeof input !== 'string' && input.constructor !== env.AST.ProgramNode)) {
     throw new Exception("You must pass a string or Handlebars AST to Handlebars.precompile. You passed " + input);
   }
 
@@ -433,13 +431,13 @@ export function precompile(input, options) {
     options.data = true;
   }
 
-  var ast = parse(input);
-  var environment = new Compiler().compile(ast, options);
-  return new JavaScriptCompiler().compile(environment, options);
+  var ast = env.parse(input);
+  var 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.constructor !== AST.ProgramNode)) {
+  if (input == null || (typeof input !== 'string' && input.constructor !== env.AST.ProgramNode)) {
     throw new Exception("You must pass a string or Handlebars AST to Handlebars.compile. You passed " + input);
   }
 
@@ -452,9 +450,9 @@ export function compile(input, options, env) {
   var compiled;
 
   function compileInput() {
-    var ast = parse(input);
-    var environment = new Compiler().compile(ast, options);
-    var templateSpec = new JavaScriptCompiler().compile(environment, options, undefined, true);
+    var ast = env.parse(input);
+    var environment = new env.Compiler().compile(ast, options);
+    var templateSpec = new env.JavaScriptCompiler().compile(environment, options, undefined, true);
     return env.template(templateSpec);
   }
 
diff --git a/lib/handlebars/compiler/javascript-compiler.js b/lib/handlebars/compiler/javascript-compiler.js
index 159a38bfc..75390685f 100644
--- a/lib/handlebars/compiler/javascript-compiler.js
+++ b/lib/handlebars/compiler/javascript-compiler.js
@@ -1,4 +1,5 @@
 import { COMPILER_REVISION, REVISION_CHANGES, log } from "../base";
+import Exception from "../exception";
 
 function Literal(value) {
   this.value = value;
@@ -76,6 +77,7 @@ JavaScriptCompiler.prototype = {
     this.stackSlot = 0;
     this.stackVars = [];
     this.registers = { list: [] };
+    this.hashes = [];
     this.compileStack = [];
     this.inlineStack = [];
 
@@ -103,6 +105,10 @@ JavaScriptCompiler.prototype = {
     // Flush any trailing content that might be pending.
     this.pushSource('');
 
+    if (this.stackSlot || this.inlineStack.length || this.compileStack.length) {
+      throw new Exception('Compile completed with content left on stack');
+    }
+
     return this.createFunctionContext(asObject);
   },
 
@@ -244,9 +250,6 @@ JavaScriptCompiler.prototype = {
     var current = this.topStack();
     params.splice(1, 0, current);
 
-    // Use the options value generated from the invocation
-    params[params.length-1] = 'options';
-
     this.pushSource("if (!" + this.lastHelper + ") { " + current + " = blockHelperMissing.call(" + params.join(", ") + "); }");
   },
 
@@ -382,7 +385,7 @@ JavaScriptCompiler.prototype = {
   //
   // Push the data lookup operator
   lookupData: function() {
-    this.push('data');
+    this.pushStackLiteral('data');
   },
 
   // [pushStringParam]
@@ -398,10 +401,14 @@ JavaScriptCompiler.prototype = {
 
     this.pushString(type);
 
-    if (typeof string === 'string') {
-      this.pushString(string);
-    } else {
-      this.pushStackLiteral(string);
+    // If it's a subexpression, the string result
+    // will be pushed after this opcode.
+    if (type !== 'sexpr') {
+      if (typeof string === 'string') {
+        this.pushString(string);
+      } else {
+        this.pushStackLiteral(string);
+      }
     }
   },
 
@@ -409,21 +416,25 @@ JavaScriptCompiler.prototype = {
     this.pushStackLiteral('{}');
 
     if (this.options.stringParams) {
-      this.register('hashTypes', '{}');
-      this.register('hashContexts', '{}');
+      this.push('{}'); // hashContexts
+      this.push('{}'); // hashTypes
     }
   },
   pushHash: function() {
+    if (this.hash) {
+      this.hashes.push(this.hash);
+    }
     this.hash = {values: [], types: [], contexts: []};
   },
   popHash: function() {
     var hash = this.hash;
-    this.hash = undefined;
+    this.hash = this.hashes.pop();
 
     if (this.options.stringParams) {
-      this.register('hashContexts', '{' + hash.contexts.join(',') + '}');
-      this.register('hashTypes', '{' + hash.types.join(',') + '}');
+      this.push('{' + hash.contexts.join(',') + '}');
+      this.push('{' + hash.types.join(',') + '}');
     }
+
     this.push('{\n    ' + hash.values.join(',\n    ') + '\n  }');
   },
 
@@ -485,18 +496,31 @@ JavaScriptCompiler.prototype = {
   // and pushes the helper's return value onto the stack.
   //
   // If the helper is not found, `helperMissing` is called.
-  invokeHelper: function(paramSize, name) {
+  invokeHelper: function(paramSize, name, isRoot) {
     this.context.aliases.helperMissing = 'helpers.helperMissing';
+    this.useRegister('helper');
 
     var helper = this.lastHelper = this.setupHelper(paramSize, name, true);
     var nonHelper = this.nameLookup('depth' + this.lastContext, name, 'context');
 
-    this.push(helper.name + ' || ' + nonHelper);
-    this.replaceStack(function(name) {
-      return name + ' ? ' + name + '.call(' +
-          helper.callParams + ") " + ": helperMissing.call(" +
-          helper.helperMissingParams + ")";
-    });
+    var lookup = 'helper = ' + helper.name + ' || ' + nonHelper;
+    if (helper.paramsInit) {
+      lookup += ',' + helper.paramsInit;
+    }
+
+    this.push(
+      '('
+        + lookup
+        + ',helper '
+          + '? helper.call(' + helper.callParams + ') '
+          + ': helperMissing.call(' + helper.helperMissingParams + '))');
+
+    // Always flush subexpressions. This is both to prevent the compounding size issue that
+    // occurs when the code has to be duplicated for inlining and also to prevent errors
+    // due to the incorrect options object being passed due to the shared register.
+    if (!isRoot) {
+      this.flushInline();
+    }
   },
 
   // [invokeKnownHelper]
@@ -525,8 +549,9 @@ JavaScriptCompiler.prototype = {
   // `knownHelpersOnly` flags at compile-time.
   invokeAmbiguous: function(name, helperCall) {
     this.context.aliases.functionType = '"function"';
+    this.useRegister('helper');
 
-    this.pushStackLiteral('{}');    // Hash value
+    this.emptyHash();
     var helper = this.setupHelper(0, name, helperCall);
 
     var helperName = this.lastHelper = this.nameLookup('helpers', name, 'helper');
@@ -534,8 +559,11 @@ JavaScriptCompiler.prototype = {
     var nonHelper = this.nameLookup('depth' + this.lastContext, name, 'context');
     var nextStack = this.nextStack();
 
-    this.pushSource('if (' + nextStack + ' = ' + helperName + ') { ' + nextStack + ' = ' + nextStack + '.call(' + helper.callParams + '); }');
-    this.pushSource('else { ' + nextStack + ' = ' + nonHelper + '; ' + nextStack + ' = typeof ' + nextStack + ' === functionType ? ' + nextStack + '.call(' + helper.callParams + ') : ' + nextStack + '; }');
+    if (helper.paramsInit) {
+      this.pushSource(helper.paramsInit);
+    }
+    this.pushSource('if (helper = ' + helperName + ') { ' + nextStack + ' = helper.call(' + helper.callParams + '); }');
+    this.pushSource('else { helper = ' + nonHelper + '; ' + nextStack + ' = typeof helper === functionType ? helper.call(' + helper.callParams + ') : helper; }');
   },
 
   // [invokePartial]
@@ -681,7 +709,9 @@ JavaScriptCompiler.prototype = {
   replaceStack: function(callback) {
     var prefix = '',
         inline = this.isInline(),
-        stack;
+        stack,
+        createdStack,
+        usedLiteral;
 
     // If we are currently inline then we want to merge the inline statement into the
     // replacement statement via ','
@@ -691,9 +721,11 @@ JavaScriptCompiler.prototype = {
       if (top instanceof Literal) {
         // Literals do not need to be inlined
         stack = top.value;
+        usedLiteral = true;
       } else {
         // Get or create the current stack name for use by the inline
-        var name = this.stackSlot ? this.topStackName() : this.incrStack();
+        createdStack = !this.stackSlot;
+        var name = !createdStack ? this.topStackName() : this.incrStack();
 
         prefix = '(' + this.push(name) + ' = ' + top + '),';
         stack = this.topStack();
@@ -705,9 +737,12 @@ JavaScriptCompiler.prototype = {
     var item = callback.call(this, stack);
 
     if (inline) {
-      if (this.inlineStack.length || this.compileStack.length) {
+      if (!usedLiteral) {
         this.popStack();
       }
+      if (createdStack) {
+        this.stackSlot--;
+      }
       this.push('(' + prefix + item + ')');
     } else {
       // Prevent modification of the context depth variable. Through replaceStack
@@ -758,6 +793,9 @@ JavaScriptCompiler.prototype = {
       return item.value;
     } else {
       if (!inline) {
+        if (!this.stackSlot) {
+          throw new Exception('Invalid stack pop');
+        }
         this.stackSlot--;
       }
       return item;
@@ -786,25 +824,29 @@ JavaScriptCompiler.prototype = {
   },
 
   setupHelper: function(paramSize, name, missingParams) {
-    var params = [];
-    this.setupParams(paramSize, params, missingParams);
+    var params = [],
+        paramsInit = this.setupParams(paramSize, params, missingParams);
     var foundHelper = this.nameLookup('helpers', name, 'helper');
 
     return {
       params: params,
+      paramsInit: paramsInit,
       name: foundHelper,
       callParams: ["depth0"].concat(params).join(", "),
       helperMissingParams: missingParams && ["depth0", this.quotedString(name)].concat(params).join(", ")
     };
   },
 
-  // the params and contexts arguments are passed in arrays
-  // to fill in
-  setupParams: function(paramSize, params, useRegister) {
+  setupOptions: function(paramSize, params) {
     var options = [], contexts = [], types = [], param, inverse, program;
 
     options.push("hash:" + this.popStack());
 
+    if (this.options.stringParams) {
+      options.push("hashTypes:" + this.popStack());
+      options.push("hashContexts:" + this.popStack());
+    }
+
     inverse = this.popStack();
     program = this.popStack();
 
@@ -817,7 +859,7 @@ JavaScriptCompiler.prototype = {
       }
 
       if (!inverse) {
-       this.context.aliases.self = "this";
+        this.context.aliases.self = "this";
         inverse = "self.noop";
       }
 
@@ -838,22 +880,28 @@ JavaScriptCompiler.prototype = {
     if (this.options.stringParams) {
       options.push("contexts:[" + contexts.join(",") + "]");
       options.push("types:[" + types.join(",") + "]");
-      options.push("hashContexts:hashContexts");
-      options.push("hashTypes:hashTypes");
     }
 
     if(this.options.data) {
       options.push("data:data");
     }
 
-    options = "{" + options.join(",") + "}";
+    return options;
+  },
+
+  // the params and contexts arguments are passed in arrays
+  // to fill in
+  setupParams: function(paramSize, params, useRegister) {
+    var options = '{' + this.setupOptions(paramSize, params).join(',') + '}';
+
     if (useRegister) {
-      this.register('options', options);
+      this.useRegister('options');
       params.push('options');
+      return 'options=' + options;
     } else {
       params.push(options);
+      return '';
     }
-    return params.join(", ");
   }
 };
 
diff --git a/lib/handlebars/compiler/printer.js b/lib/handlebars/compiler/printer.js
index f91ff0216..ad55c7d4a 100644
--- a/lib/handlebars/compiler/printer.js
+++ b/lib/handlebars/compiler/printer.js
@@ -62,8 +62,8 @@ PrintVisitor.prototype.block = function(block) {
   return out;
 };
 
-PrintVisitor.prototype.mustache = function(mustache) {
-  var params = mustache.params, paramStrings = [], hash;
+PrintVisitor.prototype.sexpr = function(sexpr) {
+  var params = sexpr.params, paramStrings = [], hash;
 
   for(var i=0, l=params.length; i<l; i++) {
     paramStrings.push(this.accept(params[i]));
@@ -71,9 +71,13 @@ PrintVisitor.prototype.mustache = function(mustache) {
 
   params = "[" + paramStrings.join(", ") + "]";
 
-  hash = mustache.hash ? " " + this.accept(mustache.hash) : "";
+  hash = sexpr.hash ? " " + this.accept(sexpr.hash) : "";
+
+  return this.accept(sexpr.id) + " " + params + hash;
+};
 
-  return this.pad("{{ " + this.accept(mustache.id) + " " + params + hash + " }}");
+PrintVisitor.prototype.mustache = function(mustache) {
+  return this.pad("{{ " + this.accept(mustache.sexpr) + " }}");
 };
 
 PrintVisitor.prototype.partial = function(partial) {
diff --git a/lib/handlebars/exception.js b/lib/handlebars/exception.js
index 6de9cfdb4..8c5c2f669 100644
--- a/lib/handlebars/exception.js
+++ b/lib/handlebars/exception.js
@@ -1,13 +1,25 @@
 
 var errorProps = ['description', 'fileName', 'lineNumber', 'message', 'name', 'number', 'stack'];
 
-function Exception(/* message */) {
-  var tmp = Error.prototype.constructor.apply(this, arguments);
+function Exception(message, node) {
+  var line;
+  if (node && node.firstLine) {
+    line = node.firstLine;
+
+    message += ' - ' + line + ':' + node.firstColumn;
+  }
+
+  var tmp = Error.prototype.constructor.call(this, message);
 
   // Unfortunately errors are not enumerable in Chrome (at least), so `for prop in tmp` doesn't work.
   for (var idx = 0; idx < errorProps.length; idx++) {
     this[errorProps[idx]] = tmp[errorProps[idx]];
   }
+
+  if (line) {
+    this.lineNumber = line;
+    this.column = node.firstColumn;
+  }
 }
 
 Exception.prototype = new Error();
diff --git a/lib/handlebars/runtime.js b/lib/handlebars/runtime.js
index 5c636457c..5ae8d8a78 100644
--- a/lib/handlebars/runtime.js
+++ b/lib/handlebars/runtime.js
@@ -10,11 +10,11 @@ export function checkRevision(compilerInfo) {
     if (compilerRevision < currentRevision) {
       var runtimeVersions = REVISION_CHANGES[currentRevision],
           compilerVersions = REVISION_CHANGES[compilerRevision];
-      throw new Error("Template was precompiled with an older version of Handlebars than the current runtime. "+
+      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 Error("Template was precompiled with a newer version of Handlebars than the current runtime. "+
+      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]+").");
     }
   }
@@ -24,7 +24,7 @@ export function checkRevision(compilerInfo) {
 
 export function template(templateSpec, env) {
   if (!env) {
-    throw new Error("No environment passed to template");
+    throw new Exception("No environment passed to template");
   }
 
   // Note: Using env.VM references rather than local var references throughout this section to allow
diff --git a/lib/index.js b/lib/index.js
index ca51d3a49..e150524bd 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -3,9 +3,9 @@
 
 // var local = handlebars.create();
 
-var handlebars = require('../dist/cjs/handlebars').default;
+var handlebars = require('../dist/cjs/handlebars')["default"];
 
-handlebars.Visitor = require('../dist/cjs/handlebars/compiler/visitor').default;
+handlebars.Visitor = require('../dist/cjs/handlebars/compiler/visitor')["default"];
 
 var printer = require('../dist/cjs/handlebars/compiler/printer');
 handlebars.PrintVisitor = printer.PrintVisitor;
diff --git a/package.json b/package.json
index 90b6be31a..6403c5d46 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "handlebars",
   "barename": "handlebars",
-  "version": "1.2.1",
+  "version": "1.3.0",
   "description": "Handlebars provides the power necessary to let you build semantic templates effectively with no frustration",
   "homepage": "http://www.handlebarsjs.com/",
   "keywords": [
diff --git a/release-notes.md b/release-notes.md
index 8c1198838..3f0fac995 100644
--- a/release-notes.md
+++ b/release-notes.md
@@ -2,7 +2,21 @@
 
 ## Development
 
-[Commits](https://github.com/wycats/handlebars.js/compare/v1.2.1...master)
+[Commits](https://github.com/wycats/handlebars.js/compare/v1.3.0...master)
+
+## v1.3.0 - January 1st, 2014
+- [#690](https://github.com/wycats/handlebars.js/pull/690) - Added support for subexpressions ([@machty](https://api.github.com/users/machty))
+- [#696](https://github.com/wycats/handlebars.js/pull/696) - Fix for reserved keyword "default" ([@nateirwin](https://api.github.com/users/nateirwin))
+- [#692](https://github.com/wycats/handlebars.js/pull/692) - add line numbers to nodes when parsing ([@fivetanley](https://api.github.com/users/fivetanley))
+- [#695](https://github.com/wycats/handlebars.js/pull/695) - Pull options out from param setup to allow easier extension ([@blakeembrey](https://api.github.com/users/blakeembrey))
+- [#694](https://github.com/wycats/handlebars.js/pull/694) - Make the environment reusable ([@blakeembrey](https://api.github.com/users/blakeembrey))
+- [#636](https://github.com/wycats/handlebars.js/issues/636) - Print line and column of errors ([@sgronblo](https://api.github.com/users/sgronblo))
+- Use literal for data lookup - c1a93d3
+- Add stack handling sanity checks - cd885bf
+- Fix stack id "leak" on replaceStack - ddfe457
+- Fix incorrect stack pop when replacing literals - f4d337d
+
+[Commits](https://github.com/wycats/handlebars.js/compare/v1.2.1...v1.3.0)
 
 ## v1.2.1 - December 26th, 2013
 - [#684](https://github.com/wycats/handlebars.js/pull/684) - Allow any number of trailing characters for valid JavaScript variable ([@blakeembrey](https://api.github.com/users/blakeembrey))
diff --git a/spec/ast.js b/spec/ast.js
index ae10a3772..46f0131f7 100644
--- a/spec/ast.js
+++ b/spec/ast.js
@@ -4,6 +4,25 @@ describe('ast', function() {
     return;
   }
 
+  var LOCATION_INFO = {
+    last_line: 0,
+    first_line: 0,
+    first_column: 0,
+    last_column: 0
+  };
+
+  function testLocationInfoStorage(node){
+    var properties = [ 'firstLine', 'lastLine', 'firstColumn', 'lastColumn' ],
+        property,
+        propertiesLen = properties.length,
+        i;
+
+    for (i = 0; i < propertiesLen; i++){
+      property = properties[0];
+      equals(node[property], 0);
+    }
+  }
+
   describe('MustacheNode', function() {
     function testEscape(open, expected) {
       var mustache = new handlebarsEnv.AST.MustacheNode([{}], {}, open, false);
@@ -13,7 +32,7 @@ describe('ast', function() {
     it('should store args', function() {
       var id = {isSimple: true},
           hash = {},
-          mustache = new handlebarsEnv.AST.MustacheNode([id, 'param1'], hash, '', false);
+          mustache = new handlebarsEnv.AST.MustacheNode([id, 'param1'], hash, '', false, LOCATION_INFO);
       equals(mustache.type, 'mustache');
       equals(mustache.hash, hash);
       equals(mustache.escaped, true);
@@ -21,6 +40,7 @@ describe('ast', function() {
       equals(mustache.params.length, 1);
       equals(mustache.params[0], 'param1');
       equals(!!mustache.isHelper, true);
+      testLocationInfoStorage(mustache);
     });
     it('should accept token for escape', function() {
       testEscape('{{', true);
@@ -48,11 +68,32 @@ describe('ast', function() {
     });
   });
   describe('BlockNode', function() {
-    it('should throw on mustache mismatch', function() {
+    it('should throw on mustache mismatch (old sexpr-less version)', function() {
       shouldThrow(function() {
-        new handlebarsEnv.AST.BlockNode({id: {original: 'foo'}}, {}, {}, {path: {original: 'bar'}});
+        var mustacheNode = new handlebarsEnv.AST.MustacheNode([{ original: 'foo'}], null, '{{', {});
+        new handlebarsEnv.AST.BlockNode(mustacheNode, {}, {}, {path: {original: 'bar'}});
       }, Handlebars.Exception, "foo doesn't match bar");
     });
+    it('should throw on mustache mismatch', function() {
+      shouldThrow(function() {
+        var sexprNode = new handlebarsEnv.AST.SexprNode([{ original: 'foo'}], null);
+        var mustacheNode = new handlebarsEnv.AST.MustacheNode(sexprNode, null, '{{', {});
+        new handlebarsEnv.AST.BlockNode(mustacheNode, {}, {}, {path: {original: 'bar'}}, {first_line: 2, first_column: 2});
+      }, Handlebars.Exception, "foo doesn't match bar - 2:2");
+    });
+
+    it('stores location info', function(){
+      var sexprNode = new handlebarsEnv.AST.SexprNode([{ original: 'foo'}], null);
+      var mustacheNode = new handlebarsEnv.AST.MustacheNode(sexprNode, null, '{{', {});
+      var block = new handlebarsEnv.AST.BlockNode(mustacheNode,
+                                                  {strip: {}}, {strip: {}},
+                                                  {
+                                                    strip: {},
+                                                    path: {original: 'foo'}
+                                                  },
+                                                  LOCATION_INFO);
+      testLocationInfoStorage(block);
+    });
   });
   describe('IdNode', function() {
     it('should throw on invalid path', function() {
@@ -61,22 +102,175 @@ describe('ast', function() {
           {part: 'foo'},
           {part: '..'},
           {part: 'bar'}
-        ]);
-      }, Handlebars.Exception, "Invalid path: foo..");
+        ], {first_line: 1, first_column: 1});
+      }, Handlebars.Exception, "Invalid path: foo.. - 1:1");
       shouldThrow(function() {
         new handlebarsEnv.AST.IdNode([
           {part: 'foo'},
           {part: '.'},
           {part: 'bar'}
-        ]);
-      }, Handlebars.Exception, "Invalid path: foo.");
+        ], {first_line: 1, first_column: 1});
+      }, Handlebars.Exception, "Invalid path: foo. - 1:1");
       shouldThrow(function() {
         new handlebarsEnv.AST.IdNode([
           {part: 'foo'},
           {part: 'this'},
           {part: 'bar'}
-        ]);
-      }, Handlebars.Exception, "Invalid path: foothis");
+        ], {first_line: 1, first_column: 1});
+      }, Handlebars.Exception, "Invalid path: foothis - 1:1");
+    });
+
+    it('stores location info', function(){
+      var idNode = new handlebarsEnv.AST.IdNode([], LOCATION_INFO);
+      testLocationInfoStorage(idNode);
+    });
+  });
+
+  describe("HashNode", function(){
+
+    it('stores location info', function(){
+      var hash = new handlebarsEnv.AST.HashNode([], LOCATION_INFO);
+      testLocationInfoStorage(hash);
+    });
+  });
+
+  describe("ContentNode", function(){
+
+    it('stores location info', function(){
+      var content = new handlebarsEnv.AST.ContentNode("HI", LOCATION_INFO);
+      testLocationInfoStorage(content);
+    });
+  });
+
+  describe("CommentNode", function(){
+
+    it('stores location info', function(){
+      var comment = new handlebarsEnv.AST.CommentNode("HI", LOCATION_INFO);
+      testLocationInfoStorage(comment);
+    });
+  });
+
+  describe("IntegerNode", function(){
+
+    it('stores location info', function(){
+      var integer = new handlebarsEnv.AST.IntegerNode("6", LOCATION_INFO);
+      testLocationInfoStorage(integer);
     });
   });
+
+  describe("StringNode", function(){
+
+    it('stores location info', function(){
+      var string = new handlebarsEnv.AST.StringNode("6", LOCATION_INFO);
+      testLocationInfoStorage(string);
+    });
+  });
+
+  describe("BooleanNode", function(){
+
+    it('stores location info', function(){
+      var bool = new handlebarsEnv.AST.BooleanNode("true", LOCATION_INFO);
+      testLocationInfoStorage(bool);
+    });
+  });
+
+  describe("DataNode", function(){
+
+    it('stores location info', function(){
+      var data = new handlebarsEnv.AST.DataNode("YES", LOCATION_INFO);
+      testLocationInfoStorage(data);
+    });
+  });
+
+  describe("PartialNameNode", function(){
+
+    it('stores location info', function(){
+      var pnn = new handlebarsEnv.AST.PartialNameNode({original: "YES"}, LOCATION_INFO);
+      testLocationInfoStorage(pnn);
+    });
+  });
+
+  describe("PartialNode", function(){
+
+    it('stores location info', function(){
+      var pn = new handlebarsEnv.AST.PartialNode("so_partial", {}, {}, LOCATION_INFO);
+      testLocationInfoStorage(pn);
+    });
+  });
+  describe("ProgramNode", function(){
+
+    describe("storing location info", function(){
+      it("stores when `inverse` argument isn't passed", function(){
+        var pn = new handlebarsEnv.AST.ProgramNode([], LOCATION_INFO);
+        testLocationInfoStorage(pn);
+      });
+
+      it("stores when `inverse` or `stripInverse` arguments passed", function(){
+        var pn = new handlebarsEnv.AST.ProgramNode([], {strip: {}}, undefined, LOCATION_INFO);
+        testLocationInfoStorage(pn);
+
+        var clone = {
+          strip: {},
+          firstLine: 0,
+          lastLine: 0,
+          firstColumn: 0,
+          lastColumn: 0
+        };
+        pn = new handlebarsEnv.AST.ProgramNode([], {strip: {}}, [ clone ], LOCATION_INFO);
+        testLocationInfoStorage(pn);
+
+        // Assert that the newly created ProgramNode has the same location
+        // information as the inverse
+        testLocationInfoStorage(pn.inverse);
+      });
+    });
+  });
+
+  describe("Line Numbers", function(){
+    var ast, statements;
+
+    function testColumns(node, firstLine, lastLine, firstColumn, lastColumn){
+      equals(node.firstLine, firstLine);
+      equals(node.lastLine, lastLine);
+      equals(node.firstColumn, firstColumn);
+      equals(node.lastColumn, lastColumn);
+    }
+
+    ast = Handlebars.parse("line 1 {{line1Token}}\n line 2 {{line2token}}\n line 3 {{#blockHelperOnLine3}}\nline 4{{line4token}}\n" +
+                           "line5{{else}}\n{{line6Token}}\n{{/blockHelperOnLine3}}");
+    statements = ast.statements;
+
+    it('gets ContentNode line numbers', function(){
+      var contentNode = statements[0];
+      testColumns(contentNode, 1, 1, 0, 7);
+    });
+
+    it('gets MustacheNode line numbers', function(){
+      var mustacheNode = statements[1];
+      testColumns(mustacheNode, 1, 1, 7, 21);
+    });
+
+    it('gets line numbers correct when newlines appear', function(){
+      var secondContentNode = statements[2];
+      testColumns(secondContentNode, 1, 2, 21, 8);
+    });
+
+    it('gets MustacheNode line numbers correct across newlines', function(){
+      var secondMustacheNode = statements[3];
+      testColumns(secondMustacheNode, 2, 2, 8, 22);
+     });
+
+     it('gets the block helper information correct', function(){
+       var blockHelperNode = statements[5];
+       testColumns(blockHelperNode, 3, 7, 8, 23);
+     });
+
+     it('correctly records the line numbers of an inverse of a block helper', function(){
+       var blockHelperNode = statements[5],
+           inverse = blockHelperNode.inverse;
+
+       testColumns(inverse, 5, 6, 13, 0);
+     });
+  });
 });
+
diff --git a/spec/env/runtime.js b/spec/env/runtime.js
index 68e40b058..e73d11115 100644
--- a/spec/env/runtime.js
+++ b/spec/env/runtime.js
@@ -8,11 +8,21 @@ var _ = require('underscore'),
 global.Handlebars = undefined;
 vm.runInThisContext(fs.readFileSync(__dirname + '/../../dist/handlebars.runtime.js'), 'dist/handlebars.runtime.js');
 
+var parse = require('../../dist/cjs/handlebars/compiler/base').parse;
 var compiler = require('../../dist/cjs/handlebars/compiler/compiler');
+var JavaScriptCompiler = require('../../dist/cjs/handlebars/compiler/javascript-compiler')['default'];
 
 global.CompilerContext = {
   compile: function(template, options) {
-    var templateSpec = compiler.precompile(template, options);
+    // Hack the compiler on to the environment for these specific tests
+    handlebarsEnv.precompile = function(template, options) {
+      return compiler.precompile(template, options, handlebarsEnv);
+    };
+    handlebarsEnv.parse = parse;
+    handlebarsEnv.Compiler = compiler.Compiler;
+    handlebarsEnv.JavaScriptCompiler = JavaScriptCompiler;
+
+    var templateSpec = handlebarsEnv.precompile(template, options);
     return handlebarsEnv.template(safeEval(templateSpec));
   },
   compileWithPartial: function(template, options) {
@@ -20,6 +30,10 @@ global.CompilerContext = {
     handlebarsEnv.compile = function(template, options) {
       return compiler.compile(template, options, handlebarsEnv);
     };
+    handlebarsEnv.parse = parse;
+    handlebarsEnv.Compiler = compiler.Compiler;
+    handlebarsEnv.JavaScriptCompiler = JavaScriptCompiler;
+
     return handlebarsEnv.compile(template, options);
   }
 };
diff --git a/spec/string-params.js b/spec/string-params.js
index 1ebb5838b..920b85592 100644
--- a/spec/string-params.js
+++ b/spec/string-params.js
@@ -142,4 +142,20 @@ describe('string params mode', function() {
 
     equals(result, "STOP ME FROM READING HACKER NEWS I need-a dad.joke wot", "Proper context variable output");
   });
+
+  it("with nested block ambiguous", function() {
+    var template = CompilerContext.compile('{{#with content}}{{#view}}{{firstName}} {{lastName}}{{/view}}{{/with}}', {stringParams: true});
+
+    var helpers  = {
+      with: function(options) {
+        return "WITH";
+      },
+      view: function() {
+        return "VIEW";
+      }
+    };
+
+    var result = template({}, {helpers: helpers});
+    equals(result, "WITH");
+  });
 });
diff --git a/spec/subexpressions.js b/spec/subexpressions.js
new file mode 100644
index 000000000..e8ade63ab
--- /dev/null
+++ b/spec/subexpressions.js
@@ -0,0 +1,166 @@
+/*global CompilerContext, shouldCompileTo */
+describe('subexpressions', function() {
+  it("arg-less helper", function() {
+    var string   = "{{foo (bar)}}!";
+    var context  = {};
+    var helpers  = {
+      foo: function(val) {
+        return val+val;
+      },
+      bar: function() {
+        return "LOL";
+      }
+    };
+    shouldCompileTo(string, [context, helpers], "LOLLOL!");
+  });
+
+  it("helper w args", function() {
+    var string   = '{{blog (equal a b)}}';
+
+    var context  = { bar: "LOL" };
+    var helpers  = {
+      blog: function(val) {
+        return "val is " + val;
+      },
+      equal: function(x, y) {
+        return x === y;
+      }
+    };
+    shouldCompileTo(string, [context, helpers], "val is true");
+  });
+
+  it("supports much nesting", function() {
+    var string   = '{{blog (equal (equal true true) true)}}';
+
+    var context  = { bar: "LOL" };
+    var helpers  = {
+      blog: function(val) {
+        return "val is " + val;
+      },
+      equal: function(x, y) {
+        return x === y;
+      }
+    };
+    shouldCompileTo(string, [context, helpers], "val is true");
+  });
+
+  it("provides each nested helper invocation its own options hash", function() {
+    var string = '{{equal (equal true true) true}}';
+
+    var lastOptions = null;
+    var helpers  = {
+      equal: function(x, y, options) {
+        if (!options || options === lastOptions) {
+          throw new Error("options hash was reused");
+        }
+        lastOptions = options;
+        return x === y;
+      }
+    };
+    shouldCompileTo(string, [{}, helpers], "true");
+  });
+
+  it("with hashes", function() {
+    var string   = '{{blog (equal (equal true true) true fun="yes")}}';
+
+    var context  = { bar: "LOL" };
+    var helpers  = {
+      blog: function(val) {
+        return "val is " + val;
+      },
+      equal: function(x, y) {
+        return x === y;
+      }
+    };
+    shouldCompileTo(string, [context, helpers], "val is true");
+  });
+
+  it("as hashes", function() {
+    var string   = '{{blog fun=(equal (blog fun=1) "val is 1")}}';
+
+    var helpers  = {
+      blog: function(options) {
+        return "val is " + options.hash.fun;
+      },
+      equal: function(x, y) {
+        return x === y;
+      }
+    };
+    shouldCompileTo(string, [{}, helpers], "val is true");
+  });
+
+  it("in string params mode,", function() {
+    var template = CompilerContext.compile('{{snog (blorg foo x=y) yeah a=b}}', {stringParams: true});
+
+    var helpers = {
+      snog: function(a, b, options) {
+        equals(a, 'foo');
+        equals(options.types.length, 2, "string params for outer helper processed correctly");
+        equals(options.types[0], 'sexpr', "string params for outer helper processed correctly");
+        equals(options.types[1], 'ID', "string params for outer helper processed correctly");
+        return a + b;
+      },
+
+      blorg: function(a, options) {
+        equals(options.types.length, 1, "string params for inner helper processed correctly");
+        equals(options.types[0], 'ID', "string params for inner helper processed correctly");
+        return a;
+      }
+    };
+
+    var result = template({
+      foo: {},
+      yeah: {}
+    }, {helpers: helpers});
+
+    equals(result, "fooyeah");
+  });
+
+  it("as hashes in string params mode", function() {
+
+    var template = CompilerContext.compile('{{blog fun=(bork)}}', {stringParams: true});
+
+    var helpers  = {
+      blog: function(options) {
+        equals(options.hashTypes.fun, 'sexpr');
+        return "val is " + options.hash.fun;
+      },
+      bork: function() {
+        return "BORK";
+      }
+    };
+
+    var result = template({}, {helpers: helpers});
+    equals(result, "val is BORK");
+  });
+
+  it("subexpression functions on the context", function() {
+    var string   = "{{foo (bar)}}!";
+    var context  = {
+      bar: function() {
+        return "LOL";
+      }
+    };
+    var helpers  = {
+      foo: function(val) {
+        return val+val;
+      }
+    };
+    shouldCompileTo(string, [context, helpers], "LOLLOL!");
+  });
+
+  it("subexpressions can't just be property lookups", function() {
+    var string   = "{{foo (bar)}}!";
+    var context  = {
+      bar: "LOL"
+    };
+    var helpers  = {
+      foo: function(val) {
+        return val+val;
+      }
+    };
+    shouldThrow(function() {
+      shouldCompileTo(string, [context, helpers], "LOLLOL!");
+    });
+  });
+});
diff --git a/spec/tokenizer.js b/spec/tokenizer.js
index 80f28ab67..841a5abc1 100644
--- a/spec/tokenizer.js
+++ b/spec/tokenizer.js
@@ -364,4 +364,31 @@ describe('Tokenizer', function() {
   it('does not time out in a mustache when invalid ID characters are used', function() {
     shouldMatchTokens(tokenize("{{foo & }}"), ['OPEN', 'ID']);
   });
+
+  it('tokenizes subexpressions', function() {
+    var result = tokenize("{{foo (bar)}}");
+    shouldMatchTokens(result, ['OPEN', 'ID', 'OPEN_SEXPR', 'ID', 'CLOSE_SEXPR', 'CLOSE']);
+    shouldBeToken(result[1], "ID", "foo");
+    shouldBeToken(result[3], "ID", "bar");
+
+    result = tokenize("{{foo (a-x b-y)}}");
+    shouldMatchTokens(result, ['OPEN', 'ID', 'OPEN_SEXPR', 'ID', 'ID', 'CLOSE_SEXPR', 'CLOSE']);
+    shouldBeToken(result[1], "ID", "foo");
+    shouldBeToken(result[3], "ID", "a-x");
+    shouldBeToken(result[4], "ID", "b-y");
+  });
+
+  it('tokenizes nested subexpressions', function() {
+    var result = tokenize("{{foo (bar (lol rofl)) (baz)}}");
+    shouldMatchTokens(result, ['OPEN', 'ID', 'OPEN_SEXPR', 'ID', 'OPEN_SEXPR', 'ID', 'ID', 'CLOSE_SEXPR', 'CLOSE_SEXPR', 'OPEN_SEXPR', 'ID', 'CLOSE_SEXPR', 'CLOSE']);
+    shouldBeToken(result[3],  "ID", "bar");
+    shouldBeToken(result[5],  "ID", "lol");
+    shouldBeToken(result[6],  "ID", "rofl");
+    shouldBeToken(result[10], "ID", "baz");
+  });
+
+  it('tokenizes nested subexpressions: literals', function() {
+    var result = tokenize("{{foo (bar (lol true) false) (baz 1) (blah 'b') (blorg \"c\")}}");
+    shouldMatchTokens(result, ['OPEN', 'ID', 'OPEN_SEXPR', 'ID', 'OPEN_SEXPR', 'ID', 'BOOLEAN', 'CLOSE_SEXPR', 'BOOLEAN', 'CLOSE_SEXPR', 'OPEN_SEXPR', 'ID', 'INTEGER', 'CLOSE_SEXPR', 'OPEN_SEXPR', 'ID', 'STRING', 'CLOSE_SEXPR', 'OPEN_SEXPR', 'ID', 'STRING', 'CLOSE_SEXPR', 'CLOSE']);
+  });
 });
diff --git a/src/handlebars.l b/src/handlebars.l
index 913121caa..996badb22 100644
--- a/src/handlebars.l
+++ b/src/handlebars.l
@@ -12,8 +12,8 @@ function strip(start, end) {
 LEFT_STRIP    "~"
 RIGHT_STRIP   "~"
 
-LOOKAHEAD           [=~}\s\/.]
-LITERAL_LOOKAHEAD   [~}\s]
+LOOKAHEAD           [=~}\s\/.)]
+LITERAL_LOOKAHEAD   [~}\s)]
 
 /*
 ID is the inverse of control characters.
@@ -51,6 +51,9 @@ ID    [^\s!"#%-,\.\/;->@\[-\^`\{-~]+/{LOOKAHEAD}
 
 <com>[\s\S]*?"--}}"              strip(0,4); this.popState(); return 'COMMENT';
 
+<mu>"("                          return 'OPEN_SEXPR';
+<mu>")"                          return 'CLOSE_SEXPR';
+
 <mu>"{{"{LEFT_STRIP}?">"         return 'OPEN_PARTIAL';
 <mu>"{{"{LEFT_STRIP}?"#"         return 'OPEN_BLOCK';
 <mu>"{{"{LEFT_STRIP}?"/"         return 'OPEN_ENDBLOCK';
diff --git a/src/handlebars.yy b/src/handlebars.yy
index 93797f5ae..7bff5125a 100644
--- a/src/handlebars.yy
+++ b/src/handlebars.yy
@@ -16,17 +16,17 @@ function stripFlags(open, close) {
 %%
 
 root
-  : statements EOF { return new yy.ProgramNode($1); }
-  | EOF { return new yy.ProgramNode([]); }
+  : statements EOF { return new yy.ProgramNode($1, @$); }
+  | EOF { return new yy.ProgramNode([], @$); }
   ;
 
 program
-  : simpleInverse statements -> new yy.ProgramNode([], $1, $2)
-  | statements simpleInverse statements -> new yy.ProgramNode($1, $2, $3)
-  | statements simpleInverse -> new yy.ProgramNode($1, $2, [])
-  | statements -> new yy.ProgramNode($1)
-  | simpleInverse -> new yy.ProgramNode([])
-  | "" -> new yy.ProgramNode([])
+  : simpleInverse statements -> new yy.ProgramNode([], $1, $2, @$)
+  | statements simpleInverse statements -> new yy.ProgramNode($1, $2, $3, @$)
+  | statements simpleInverse -> new yy.ProgramNode($1, $2, [], @$)
+  | statements -> new yy.ProgramNode($1, @$)
+  | simpleInverse -> new yy.ProgramNode([], @$)
+  | "" -> new yy.ProgramNode([], @$)
   ;
 
 statements
@@ -35,20 +35,20 @@ statements
   ;
 
 statement
-  : openInverse program closeBlock -> new yy.BlockNode($1, $2.inverse, $2, $3)
-  | openBlock program closeBlock -> new yy.BlockNode($1, $2, $2.inverse, $3)
+  : openInverse program closeBlock -> new yy.BlockNode($1, $2.inverse, $2, $3, @$)
+  | openBlock program closeBlock -> new yy.BlockNode($1, $2, $2.inverse, $3, @$)
   | mustache -> $1
   | partial -> $1
-  | CONTENT -> new yy.ContentNode($1)
-  | COMMENT -> new yy.CommentNode($1)
+  | CONTENT -> new yy.ContentNode($1, @$)
+  | COMMENT -> new yy.CommentNode($1, @$)
   ;
 
 openBlock
-  : OPEN_BLOCK inMustache CLOSE -> new yy.MustacheNode($2[0], $2[1], $1, stripFlags($1, $3))
+  : OPEN_BLOCK sexpr CLOSE -> new yy.MustacheNode($2, null, $1, stripFlags($1, $3), @$)
   ;
 
 openInverse
-  : OPEN_INVERSE inMustache CLOSE -> new yy.MustacheNode($2[0], $2[1], $1, stripFlags($1, $3))
+  : OPEN_INVERSE sexpr CLOSE -> new yy.MustacheNode($2, null, $1, stripFlags($1, $3), @$)
   ;
 
 closeBlock
@@ -58,34 +58,34 @@ closeBlock
 mustache
   // Parsing out the '&' escape token at AST level saves ~500 bytes after min due to the removal of one parser node.
   // This also allows for handler unification as all mustache node instances can utilize the same handler
-  : OPEN inMustache CLOSE -> new yy.MustacheNode($2[0], $2[1], $1, stripFlags($1, $3))
-  | OPEN_UNESCAPED inMustache CLOSE_UNESCAPED -> new yy.MustacheNode($2[0], $2[1], $1, stripFlags($1, $3))
+  : OPEN sexpr CLOSE -> new yy.MustacheNode($2, null, $1, stripFlags($1, $3), @$)
+  | OPEN_UNESCAPED sexpr CLOSE_UNESCAPED -> new yy.MustacheNode($2, null, $1, stripFlags($1, $3), @$)
   ;
 
-
 partial
-  : OPEN_PARTIAL partialName path? CLOSE -> new yy.PartialNode($2, $3, stripFlags($1, $4))
+  : OPEN_PARTIAL partialName path? CLOSE -> new yy.PartialNode($2, $3, stripFlags($1, $4), @$)
   ;
 
 simpleInverse
   : OPEN_INVERSE CLOSE -> stripFlags($1, $2)
   ;
 
-inMustache
-  : path param* hash? -> [[$1].concat($2), $3]
-  | dataName -> [[$1], null]
+sexpr
+  : path param* hash? -> new yy.SexprNode([$1].concat($2), $3, @$)
+  | dataName -> new yy.SexprNode([$1], null, @$)
   ;
 
 param
   : path -> $1
-  | STRING -> new yy.StringNode($1)
-  | INTEGER -> new yy.IntegerNode($1)
-  | BOOLEAN -> new yy.BooleanNode($1)
+  | STRING -> new yy.StringNode($1, @$)
+  | INTEGER -> new yy.IntegerNode($1, @$)
+  | BOOLEAN -> new yy.BooleanNode($1, @$)
   | dataName -> $1
+  | OPEN_SEXPR sexpr CLOSE_SEXPR {$2.isHelper = true; $$ = $2;}
   ;
 
 hash
-  : hashSegment+ -> new yy.HashNode($1)
+  : hashSegment+ -> new yy.HashNode($1, @$)
   ;
 
 hashSegment
@@ -93,17 +93,17 @@ hashSegment
   ;
 
 partialName
-  : path -> new yy.PartialNameNode($1)
-  | STRING -> new yy.PartialNameNode(new yy.StringNode($1))
-  | INTEGER -> new yy.PartialNameNode(new yy.IntegerNode($1))
+  : path -> new yy.PartialNameNode($1, @$)
+  | STRING -> new yy.PartialNameNode(new yy.StringNode($1, @$), @$)
+  | INTEGER -> new yy.PartialNameNode(new yy.IntegerNode($1, @$))
   ;
 
 dataName
-  : DATA path -> new yy.DataNode($2)
+  : DATA path -> new yy.DataNode($2, @$)
   ;
 
 path
-  : pathSegments -> new yy.IdNode($1)
+  : pathSegments -> new yy.IdNode($1, @$)
   ;
 
 pathSegments