diff --git a/lib/compiler/passes/generate-javascript.js b/lib/compiler/passes/generate-javascript.js
index 0c57d24..7d48bda 100644
--- a/lib/compiler/passes/generate-javascript.js
+++ b/lib/compiler/passes/generate-javascript.js
@@ -668,7 +668,7 @@ module.exports = function(ast, options) {
     '   * http://pegjs.majda.cz/',
     '   */',
     '',
-    '  function subclass(child, parent) {',
+    '  function peg$subclass(child, parent) {',
     '    function ctor() { this.constructor = child; }',
     '    ctor.prototype = parent.prototype;',
     '    child.prototype = new ctor();',
@@ -735,7 +735,7 @@ module.exports = function(ast, options) {
     '    this.message  = buildMessage(expected, found);',
     '  }',
     '',
-    '  subclass(SyntaxError, Error);',
+    '  peg$subclass(SyntaxError, Error);',
     '',
     '  function parse(input) {',
     '    var options = arguments.length > 1 ? arguments[1] : {},',
diff --git a/lib/parser.js b/lib/parser.js
index d8ad3b5..5e98ee7 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -5,7 +5,7 @@ module.exports = (function() {
    * http://pegjs.majda.cz/
    */
 
-  function subclass(child, parent) {
+  function peg$subclass(child, parent) {
     function ctor() { this.constructor = child; }
     ctor.prototype = parent.prototype;
     child.prototype = new ctor();
@@ -62,7 +62,7 @@ module.exports = (function() {
     this.message  = buildMessage(expected, found);
   }
 
-  subclass(SyntaxError, Error);
+  peg$subclass(SyntaxError, Error);
 
   function parse(input) {
     var options = arguments.length > 1 ? arguments[1] : {},