IE7 doesn't like seeing reserved words crop up anywhere other than wh…

…ere they're supposed to.

lib/lexer.js

@@ -244,7 +244,7 @@ Lexer.prototype = {
    * Extends.
    */
 
-  extends: function() {
+  "extends": function() {
     return this.scan(/^extends +([^\n]+)/, 'extends');
   },
 
@@ -316,7 +316,7 @@ Lexer.prototype = {
    * Case.
    */
 
-  case: function() {
+  "case": function() {
     return this.scan(/^case +([^\n]+)/, 'case');
   },
 
@@ -332,7 +332,7 @@ Lexer.prototype = {
    * Default.
    */
 
-  default: function() {
+  "default": function() {
     return this.scan(/^default */, 'default');
   },
 
@@ -390,7 +390,7 @@ Lexer.prototype = {
    * While.
    */
 
-  while: function() {
+  "while": function() {
     var captures;
     if (captures = /^while +([^\n]+)/.exec(this.input)) {
       this.consume(captures[0].length);
@@ -680,18 +680,18 @@ Lexer.prototype = {
       || this.pipelessText()
       || this.yield()
       || this.doctype()
-      || this.case()
+      || this["case"]()
       || this.when()
-      || this.default()
-      || this.extends()
+      || this["default"]()
+      || this["extends"]()
       || this.append()
       || this.prepend()
       || this.block()
       || this.include()
       || this.mixin()
       || this.conditional()
       || this.each()
-      || this.while()
+      || this["while"]()
       || this.assignment()
       || this.tag()
       || this.filter()