Allow this references in literal statements

Fixes #967

lib/handlebars/compiler/helpers.js

@@ -12,6 +12,14 @@ export function SourceLocation(source, locInfo) {
   };
 }
 
+export function id(token) {
+  if (/^\[.*\]$/.test(token)) {
+    return token.substr(1, token.length - 2);
+  } else {
+    return token;
+  }
+}
+
 export function stripFlags(open, close) {
   return {
     open: open.charAt(2) === '~',
@@ -34,10 +42,13 @@ export function preparePath(data, parts, locInfo) {
       depthString = '';
 
   for(var i=0,l=parts.length; i<l; i++) {
-    var part = parts[i].part;
+    var 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;
     original += (parts[i].separator || '') + part;
 
-    if (part === '..' || part === '.' || part === 'this') {
+    if (!isLiteral && (part === '..' || part === '.' || part === 'this')) {
       if (dig.length > 0) {
         throw new Exception('Invalid path: ' + original, {loc: locInfo});
       } else if (part === '..') {

spec/basic.js

@@ -227,10 +227,12 @@ describe("basic context", function() {
   });
 
   it("this keyword nested inside path", function() {
-    var string = "{{#hellos}}{{text/this/foo}}{{/hellos}}";
     shouldThrow(function() {
-      CompilerContext.compile(string);
+      CompilerContext.compile('{{#hellos}}{{text/this/foo}}{{/hellos}}');
-    }, Error);
+    }, Error, 'Invalid path: text/this - 1:13');
+
+    shouldCompileTo('{{[this]}}', {'this': 'bar'}, 'bar');
+    shouldCompileTo('{{text/[this]}}', {text: {'this': 'bar'}}, 'bar');
   });
 
   it("this keyword in helpers", function() {
@@ -251,7 +253,16 @@ describe("basic context", function() {
     var string = "{{#hellos}}{{foo text/this/foo}}{{/hellos}}";
     shouldThrow(function() {
       CompilerContext.compile(string);
-    }, Error);
+    }, Error, 'Invalid path: text/this - 1:17');
+
+    shouldCompileTo(
+        '{{foo [this]}}',
+        {foo: function(value) { return value; }, 'this': 'bar'},
+        'bar');
+    shouldCompileTo(
+        '{{foo text/[this]}}',
+        {foo: function(value) { return value; }, text: {'this': 'bar'}},
+        'bar');
   });
 
   it('pass string literals', function() {

src/handlebars.l

@@ -110,7 +110,7 @@ ID    [^\s!"#%-,\.\/;->@\[-\^`\{-~]+/{LOOKAHEAD}
 
 <mu>{ID}                         return 'ID';
 
-<mu>'['[^\]]*']'                 yytext = strip(1,2); return 'ID';
+<mu>'['[^\]]*']'                 return 'ID';
 <mu>.                            return 'INVALID';
 
 <INITIAL,mu><<EOF>>              return 'EOF';

src/handlebars.yy

@@ -94,11 +94,11 @@ hash
   ;
 
 hashSegment
-  : ID EQUALS param -> new yy.HashPair($1, $3, yy.locInfo(@$))
+  : ID EQUALS param -> new yy.HashPair(yy.id($1), $3, yy.locInfo(@$))
   ;
 
 blockParams
-  : OPEN_BLOCK_PARAMS ID+ CLOSE_BLOCK_PARAMS -> $2
+  : OPEN_BLOCK_PARAMS ID+ CLOSE_BLOCK_PARAMS -> yy.id($2)
   ;
 
 helperName
@@ -125,6 +125,6 @@ path
   ;
 
 pathSegments
-  : pathSegments SEP ID { $1.push({part: $3, separator: $2}); $$ = $1; }
+  : pathSegments SEP ID { $1.push({part: yy.id($3), original: $3, separator: $2}); $$ = $1; }
-  | ID -> [{part: $1}]
+  | ID -> [{part: yy.id($1), original: $1}]
   ;