AST refactoring 4/6: Rewrite compilation to not extend the AST nodes

lib/compiler.js

@@ -47,8 +47,8 @@ PEG.ArrayUtils = {
   },
 
   /*
-   * The code needs to be in sync with a code template in
-   * PEG.Grammar.Action.prototype.compile.
+   * The code needs to be in sync with the code template in the compilation
+   * function for "action" nodes.
    */
   contains: function(array, value) {
     /*
@@ -90,8 +90,8 @@ PEG.StringUtils = {
    * Surrounds the string with quotes and escapes characters inside so that the
    * result is a valid JavaScript string.
    *
-   * The code needs to be in sync with a code template in
-   * PEG.Grammar.Action.prototype.compile.
+   * The code needs to be in sync with th code template in the compilation
+   * function for "action" nodes.
    */
   quote: function(s) {
     /*
@@ -447,6 +447,397 @@ PEG.Compiler = {
     }
   ],
 
+  _compileFunctions: {
+    rule: function(node) {
+      var resultVar = PEG.Compiler.generateUniqueIdentifier("result");
+
+      if (node.displayName !== null) {
+        var setReportMatchFailuresCode = PEG.Compiler.formatCode(
+          "var savedReportMatchFailures = context.reportMatchFailures;",
+          "context.reportMatchFailures = false;"
+        );
+        var restoreReportMatchFailuresCode = PEG.Compiler.formatCode(
+          "context.reportMatchFailures = savedReportMatchFailures;"
+        );
+        var reportMatchFailureCode = PEG.Compiler.formatCode(
+          "if (context.reportMatchFailures && ${resultVar} === null) {",
+          "  this._matchFailed(${displayName|string});",
+          "}",
+          {
+            displayName: node.displayName,
+            resultVar:   resultVar
+          }
+        );
+      } else {
+        var setReportMatchFailuresCode = "";
+        var restoreReportMatchFailuresCode = "";
+        var reportMatchFailureCode = "";
+      }
+
+      return PEG.Compiler.formatCode(
+        "_parse_${name}: function(context) {",
+        "  var cacheKey = ${name|string} + '@' + this._pos;",
+        "  var cachedResult = this._cache[cacheKey];",
+        "  if (cachedResult !== undefined) {",
+        "    this._pos = cachedResult.nextPos;",
+        "    return cachedResult.result;",
+        "  }",
+        "  ",
+        "  var pos = this._pos;",
+        "  ",
+        "  ${setReportMatchFailuresCode}",
+        "  ${code}",
+        "  ${restoreReportMatchFailuresCode}",
+        "  ${reportMatchFailureCode}",
+        "  ",
+        "  this._cache[cacheKey] = {",
+        "    nextPos: this._pos,",
+        "    result:  ${resultVar}",
+        "  };",
+        "  return ${resultVar};",
+        "},",
+        {
+          name:                           node.name,
+          setReportMatchFailuresCode:     setReportMatchFailuresCode,
+          restoreReportMatchFailuresCode: restoreReportMatchFailuresCode,
+          reportMatchFailureCode:         reportMatchFailureCode,
+          code:                           PEG.Compiler.compileNode(node.expression, resultVar),
+          resultVar:                      resultVar
+        }
+      );
+    },
+
+    /*
+     * The contract for all code fragments generated by the following functions
+     * is as follows:
+     *
+     * * The code fragment should try to match a part of the input starting with
+     *   the position indicated in |this._pos|. That position may point past the
+     *   end of the input.
+     *
+     * * If the code fragment matches the input, it advances |this._pos| after
+     *   the matched part of the input and sets variable with a name stored in
+     *   |resultVar| to appropriate value, which is always non-null.
+     *
+     * * If the code fragment does not match the input, it does not change
+     *   |this._pos| and it sets a variable with a name stored in |resultVar| to
+     *   |null|.
+     */
+
+    choice: function(node, resultVar) {
+      var code = PEG.Compiler.formatCode(
+        "var ${resultVar} = null;",
+        { resultVar: resultVar }
+      );
+
+      for (var i = node.alternatives.length - 1; i >= 0; i--) {
+        var alternativeResultVar = PEG.Compiler.generateUniqueIdentifier("result");
+        code = PEG.Compiler.formatCode(
+          "${alternativeCode}",
+          "if (${alternativeResultVar} !== null) {",
+          "  var ${resultVar} = ${alternativeResultVar};",
+          "} else {",
+          "  ${code};",
+          "}",
+          {
+            alternativeCode:      PEG.Compiler.compileNode(node.alternatives[i], alternativeResultVar),
+            alternativeResultVar: alternativeResultVar,
+            code:                 code,
+            resultVar:            resultVar
+          }
+        );
+      }
+
+      return code;
+    },
+
+    sequence: function(node, resultVar) {
+      var savedPosVar = PEG.Compiler.generateUniqueIdentifier("savedPos");
+
+      var elementResultVars = PEG.ArrayUtils.map(node.elements, function() {
+        return PEG.Compiler.generateUniqueIdentifier("result")
+      });
+
+      var code = PEG.Compiler.formatCode(
+        "var ${resultVar} = ${elementResultVarArray};",
+        {
+          resultVar:             resultVar,
+          elementResultVarArray: "[" + elementResultVars.join(", ") + "]"
+        }
+      );
+
+      for (var i = node.elements.length - 1; i >= 0; i--) {
+        code = PEG.Compiler.formatCode(
+          "${elementCode}",
+          "if (${elementResultVar} !== null) {",
+          "  ${code}",
+          "} else {",
+          "  var ${resultVar} = null;",
+          "  this._pos = ${savedPosVar};",
+          "}",
+          {
+            elementCode:      PEG.Compiler.compileNode(node.elements[i], elementResultVars[i]),
+            elementResultVar: elementResultVars[i],
+            code:             code,
+            savedPosVar:      savedPosVar,
+            resultVar:        resultVar
+          }
+        );
+      }
+
+      return PEG.Compiler.formatCode(
+        "var ${savedPosVar} = this._pos;",
+        "${code}",
+        {
+          code:        code,
+          savedPosVar: savedPosVar
+        }
+      );
+    },
+
+    and_predicate: function(node, resultVar) {
+      var savedPosVar                 = PEG.Compiler.generateUniqueIdentifier("savedPos");
+      var savedReportMatchFailuresVar = PEG.Compiler.generateUniqueIdentifier("savedReportMatchFailuresVar");
+      var expressionResultVar         = PEG.Compiler.generateUniqueIdentifier("result");
+
+      return PEG.Compiler.formatCode(
+        "var ${savedPosVar} = this._pos;",
+        "var ${savedReportMatchFailuresVar} = context.reportMatchFailures;",
+        "context.reportMatchFailures = false;",
+        "${expressionCode}",
+        "context.reportMatchFailures = ${savedReportMatchFailuresVar};",
+        "if (${expressionResultVar} !== null) {",
+        "  var ${resultVar} = '';",
+        "  this._pos = ${savedPosVar};",
+        "} else {",
+        "  var ${resultVar} = null;",
+        "}",
+        {
+          expressionCode:              PEG.Compiler.compileNode(node.expression, expressionResultVar),
+          expressionResultVar:         expressionResultVar,
+          savedPosVar:                 savedPosVar,
+          savedReportMatchFailuresVar: savedReportMatchFailuresVar,
+          resultVar:                   resultVar
+        }
+      );
+    },
+
+    not_predicate: function(node, resultVar) {
+      var savedPosVar                 = PEG.Compiler.generateUniqueIdentifier("savedPos");
+      var savedReportMatchFailuresVar = PEG.Compiler.generateUniqueIdentifier("savedReportMatchFailuresVar");
+      var expressionResultVar         = PEG.Compiler.generateUniqueIdentifier("result");
+
+      return PEG.Compiler.formatCode(
+        "var ${savedPosVar} = this._pos;",
+        "var ${savedReportMatchFailuresVar} = context.reportMatchFailures;",
+        "context.reportMatchFailures = false;",
+        "${expressionCode}",
+        "context.reportMatchFailures = ${savedReportMatchFailuresVar};",
+        "if (${expressionResultVar} === null) {",
+        "  var ${resultVar} = '';",
+        "} else {",
+        "  var ${resultVar} = null;",
+        "  this._pos = ${savedPosVar};",
+        "}",
+        {
+          expressionCode:              PEG.Compiler.compileNode(node.expression, expressionResultVar),
+          expressionResultVar:         expressionResultVar,
+          savedPosVar:                 savedPosVar,
+          savedReportMatchFailuresVar: savedReportMatchFailuresVar,
+          resultVar:                   resultVar
+        }
+      );
+    },
+
+    optional: function(node, resultVar) {
+      var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
+
+      return PEG.Compiler.formatCode(
+        "${expressionCode}",
+        "var ${resultVar} = ${expressionResultVar} !== null ? ${expressionResultVar} : '';",
+        {
+          expressionCode:      PEG.Compiler.compileNode(node.expression, expressionResultVar),
+          expressionResultVar: expressionResultVar,
+          resultVar:           resultVar
+        }
+      );
+    },
+
+    zero_or_more: function(node, resultVar) {
+      var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
+
+      return PEG.Compiler.formatCode(
+        "var ${resultVar} = [];",
+        "${expressionCode}",
+        "while (${expressionResultVar} !== null) {",
+        "  ${resultVar}.push(${expressionResultVar});",
+        "  ${expressionCode}",
+        "}",
+        {
+          expressionCode:      PEG.Compiler.compileNode(node.expression, expressionResultVar),
+          expressionResultVar: expressionResultVar,
+          resultVar:           resultVar
+        }
+      );
+    },
+
+    one_or_more: function(node, resultVar) {
+      var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
+
+      return PEG.Compiler.formatCode(
+        "${expressionCode}",
+        "if (${expressionResultVar} !== null) {",
+        "  var ${resultVar} = [];",
+        "  while (${expressionResultVar} !== null) {",
+        "    ${resultVar}.push(${expressionResultVar});",
+        "    ${expressionCode}",
+        "  }",
+        "} else {",
+        "  var ${resultVar} = null;",
+        "}",
+        {
+          expressionCode:      PEG.Compiler.compileNode(node.expression, expressionResultVar),
+          expressionResultVar: expressionResultVar,
+          resultVar:           resultVar
+        }
+      );
+    },
+
+    action: function(node, resultVar) {
+      /*
+       * In case of sequences, we splat their elements into function arguments
+       * one by one. Example:
+       *
+       *   start: "a" "b" "c" { alert(arguments.length) }     // => 3
+       *
+       * This behavior is reflected in this function.
+       */
+
+      var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
+
+      if (node.expression instanceof PEG.Grammar.Sequence) {
+        var params = PEG.ArrayUtils.map(
+          PEG.ArrayUtils.range(1, node.expression.elements.length + 1),
+          function(n) { return "$" + n; }
+        ).join(", ");
+
+        var invocationCode = PEG.Compiler.formatCode(
+          "(function(${params}) { ${action} }).apply(null, ${expressionResultVar})",
+          {
+            params:              params,
+            action:              node.action,
+            expressionResultVar: expressionResultVar
+          }
+        );
+      } else {
+        var invocationCode = PEG.Compiler.formatCode(
+          "(function($1) { ${action} })(${expressionResultVar})",
+          {
+            action:              node.action,
+            expressionResultVar: expressionResultVar
+          }
+        );
+      }
+
+      return PEG.Compiler.formatCode(
+        "${expressionCode}",
+        "var ${resultVar} = ${expressionResultVar} !== null",
+        "  ? ${invocationCode}",
+        "  : null;",
+        {
+          expressionCode:      PEG.Compiler.compileNode(node.expression, expressionResultVar),
+          expressionResultVar: expressionResultVar,
+          invocationCode:      invocationCode,
+          resultVar:           resultVar
+        }
+      );
+    },
+
+    rule_ref: function(node, resultVar) {
+      return PEG.Compiler.formatCode(
+        "var ${resultVar} = this.${ruleMethod}(context);",
+        {
+          ruleMethod: "_parse_" + node.name,
+          resultVar:  resultVar
+        }
+      );
+    },
+
+    literal: function(node, resultVar) {
+      return PEG.Compiler.formatCode(
+        "if (this._input.substr(this._pos, ${length}) === ${value|string}) {",
+        "  var ${resultVar} = ${value|string};",
+        "  this._pos += ${length};",
+        "} else {",
+        "  var ${resultVar} = null;",
+        "  if (context.reportMatchFailures) {",
+        "    this._matchFailed(this._quoteString(${value|string}));",
+        "  }",
+        "}",
+        {
+          value:     node.value,
+          length:    node.value.length,
+          resultVar: resultVar
+        }
+      );
+    },
+
+    any: function(node, resultVar) {
+      return PEG.Compiler.formatCode(
+        "if (this._input.length > this._pos) {",
+        "  var ${resultVar} = this._input.charAt(this._pos);",
+        "  this._pos++;",
+        "} else {",
+        "  var ${resultVar} = null;",
+        "  if (context.reportMatchFailures) {",
+        "    this._matchFailed('any character');",
+        "  }",
+        "}",
+        { resultVar: resultVar }
+      );
+    },
+
+    "class": function(node, resultVar) {
+      /*
+       * Stupid IE considers regexps /[]/ and /[^]/ syntactically invalid, so we
+       * translate them into euqivalents it can handle.
+       */
+      if (node.characters === "") {
+        var regexp = "/^(?!)/";
+      } else if (node.characters === "^") {
+        var regexp = "/^[\\S\\s]/";
+      } else {
+        var regexp = "/^[" + node.characters + "]/";
+      }
+
+      return PEG.Compiler.formatCode(
+        "if (this._input.substr(this._pos).match(${regexp}) !== null) {",
+        "  var ${resultVar} = this._input.charAt(this._pos);",
+        "  this._pos++;",
+        "} else {",
+        "  var ${resultVar} = null;",
+        "  if (context.reportMatchFailures) {",
+        "    this._matchFailed('[' + ${characters|string} + ']');",
+        "  }",
+        "}",
+        {
+          characters: node.characters,
+          regexp:     regexp,
+          resultVar:  resultVar
+        }
+      );
+    }
+  },
+
+  /*
+   * Compiles an AST node and returns the generated code. The |resultVar|
+   * parameter contains a name of variable in which the match result will be
+   * stored in the generated code.
+   */
+  compileNode: function(node, resultVar) {
+    return this._compileFunctions[node.type](node, resultVar);
+  },
+
   /*
    * Generates a parser from a specified grammar AST and start rule. Throws
    * |PEG.Grammar.GrammarError| if the AST contains a semantic error. Note that
@@ -466,7 +857,7 @@ PEG.Compiler = {
 
     var parseFunctionDefinitions = [];
     for (var rule in ast) {
-      parseFunctionDefinitions.push(ast[rule].compile());
+      parseFunctionDefinitions.push(this.compileNode(ast[rule]));
     }
 
     var source = this.formatCode(
@@ -671,385 +1062,4 @@ PEG.Compiler = {
   }
 };
 
-PEG.Grammar.Rule.prototype.compile = function() {
-  var resultVar = PEG.Compiler.generateUniqueIdentifier("result");
-
-  if (this.displayName !== null) {
-    var setReportMatchFailuresCode = PEG.Compiler.formatCode(
-      "var savedReportMatchFailures = context.reportMatchFailures;",
-      "context.reportMatchFailures = false;"
-    );
-    var restoreReportMatchFailuresCode = PEG.Compiler.formatCode(
-      "context.reportMatchFailures = savedReportMatchFailures;"
-    );
-    var reportMatchFailureCode = PEG.Compiler.formatCode(
-      "if (context.reportMatchFailures && ${resultVar} === null) {",
-      "  this._matchFailed(${displayName|string});",
-      "}",
-      {
-        displayName: this.displayName,
-        resultVar: resultVar
-      }
-    );
-  } else {
-    var setReportMatchFailuresCode = "";
-    var restoreReportMatchFailuresCode = "";
-    var reportMatchFailureCode = "";
-  }
-
-  return PEG.Compiler.formatCode(
-    "_parse_${name}: function(context) {",
-    "  var cacheKey = ${name|string} + '@' + this._pos;",
-    "  var cachedResult = this._cache[cacheKey];",
-    "  if (cachedResult !== undefined) {",
-    "    this._pos = cachedResult.nextPos;",
-    "    return cachedResult.result;",
-    "  }",
-    "  ",
-    "  var pos = this._pos;",
-    "  ",
-    "  ${setReportMatchFailuresCode}",
-    "  ${code}",
-    "  ${restoreReportMatchFailuresCode}",
-    "  ${reportMatchFailureCode}",
-    "  ",
-    "  this._cache[cacheKey] = {",
-    "    nextPos: this._pos,",
-    "    result:  ${resultVar}",
-    "  };",
-    "  return ${resultVar};",
-    "},",
-    {
-      name:                           this.name,
-      setReportMatchFailuresCode:     setReportMatchFailuresCode,
-      restoreReportMatchFailuresCode: restoreReportMatchFailuresCode,
-      reportMatchFailureCode:         reportMatchFailureCode,
-      code:                           this.expression.compile(resultVar),
-      resultVar:                      resultVar
-    }
-  );
-};
-
-/*
- * The contract for all code fragments generated by the following |compile|
- * methods is as follows:
- *
- * * The code fragment should try to match a part of the input starting with the
- *   position indicated in |this._pos|. That position may point past the end of
- *   the input.
- *
- * * If the code fragment matches the input, it advances |this._pos| after the
- *   matched part of the input and sets variable with a name stored in
- *   |resultVar| to appropriate value, which is always non-null.
- *
- * * If the code fragment does not match the input, it does not change
- *   |this._pos| and it sets a variable with a name stored in |resultVar| to
- *   |null|.
- */
-
-PEG.Grammar.Choice.prototype.compile = function(resultVar) {
-  var code = PEG.Compiler.formatCode(
-    "var ${resultVar} = null;",
-    { resultVar: resultVar }
-  );
-
-  for (var i = this.alternatives.length - 1; i >= 0; i--) {
-    var alternativeResultVar = PEG.Compiler.generateUniqueIdentifier("result");
-    code = PEG.Compiler.formatCode(
-      "${alternativeCode}",
-      "if (${alternativeResultVar} !== null) {",
-      "  var ${resultVar} = ${alternativeResultVar};",
-      "} else {",
-      "  ${code};",
-      "}",
-      {
-        alternativeCode:      this.alternatives[i].compile(alternativeResultVar),
-        alternativeResultVar: alternativeResultVar,
-        code:                 code,
-        resultVar:            resultVar
-      }
-    );
-  }
-
-  return code;
-};
-
-PEG.Grammar.Sequence.prototype.compile = function(resultVar) {
-  var savedPosVar = PEG.Compiler.generateUniqueIdentifier("savedPos");
-
-  var elementResultVars = PEG.ArrayUtils.map(this.elements, function() {
-    return PEG.Compiler.generateUniqueIdentifier("result")
-  });
-
-  var code = PEG.Compiler.formatCode(
-    "var ${resultVar} = ${elementResultVarArray};",
-    {
-      resultVar:             resultVar,
-      elementResultVarArray: "[" + elementResultVars.join(", ") + "]"
-    }
-  );
-
-  for (var i = this.elements.length - 1; i >= 0; i--) {
-    code = PEG.Compiler.formatCode(
-      "${elementCode}",
-      "if (${elementResultVar} !== null) {",
-      "  ${code}",
-      "} else {",
-      "  var ${resultVar} = null;",
-      "  this._pos = ${savedPosVar};",
-      "}",
-      {
-        elementCode:      this.elements[i].compile(elementResultVars[i]),
-        elementResultVar: elementResultVars[i],
-        code:             code,
-        savedPosVar:      savedPosVar,
-        resultVar:        resultVar
-      }
-    );
-  }
-
-  return PEG.Compiler.formatCode(
-    "var ${savedPosVar} = this._pos;",
-    "${code}",
-    {
-      code:        code,
-      savedPosVar: savedPosVar
-    }
-  );
-};
-
-PEG.Grammar.AndPredicate.prototype.compile = function(resultVar) {
-  var savedPosVar                 = PEG.Compiler.generateUniqueIdentifier("savedPos");
-  var savedReportMatchFailuresVar = PEG.Compiler.generateUniqueIdentifier("savedReportMatchFailuresVar");
-  var expressionResultVar         = PEG.Compiler.generateUniqueIdentifier("result");
-
-  return PEG.Compiler.formatCode(
-    "var ${savedPosVar} = this._pos;",
-    "var ${savedReportMatchFailuresVar} = context.reportMatchFailures;",
-    "context.reportMatchFailures = false;",
-    "${expressionCode}",
-    "context.reportMatchFailures = ${savedReportMatchFailuresVar};",
-    "if (${expressionResultVar} !== null) {",
-    "  var ${resultVar} = '';",
-    "  this._pos = ${savedPosVar};",
-    "} else {",
-    "  var ${resultVar} = null;",
-    "}",
-    {
-      expressionCode:              this.expression.compile(expressionResultVar),
-      expressionResultVar:         expressionResultVar,
-      savedPosVar:                 savedPosVar,
-      savedReportMatchFailuresVar: savedReportMatchFailuresVar,
-      resultVar:                   resultVar
-    }
-  );
-};
-
-PEG.Grammar.NotPredicate.prototype.compile = function(resultVar) {
-  var savedPosVar                 = PEG.Compiler.generateUniqueIdentifier("savedPos");
-  var savedReportMatchFailuresVar = PEG.Compiler.generateUniqueIdentifier("savedReportMatchFailuresVar");
-  var expressionResultVar         = PEG.Compiler.generateUniqueIdentifier("result");
-
-  return PEG.Compiler.formatCode(
-    "var ${savedPosVar} = this._pos;",
-    "var ${savedReportMatchFailuresVar} = context.reportMatchFailures;",
-    "context.reportMatchFailures = false;",
-    "${expressionCode}",
-    "context.reportMatchFailures = ${savedReportMatchFailuresVar};",
-    "if (${expressionResultVar} === null) {",
-    "  var ${resultVar} = '';",
-    "} else {",
-    "  var ${resultVar} = null;",
-    "  this._pos = ${savedPosVar};",
-    "}",
-    {
-      expressionCode:              this.expression.compile(expressionResultVar),
-      expressionResultVar:         expressionResultVar,
-      savedPosVar:                 savedPosVar,
-      savedReportMatchFailuresVar: savedReportMatchFailuresVar,
-      resultVar:                   resultVar
-    }
-  );
-};
-
-PEG.Grammar.Optional.prototype.compile = function(resultVar) {
-  var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
-
-  return PEG.Compiler.formatCode(
-    "${expressionCode}",
-    "var ${resultVar} = ${expressionResultVar} !== null ? ${expressionResultVar} : '';",
-    {
-      expressionCode:      this.expression.compile(expressionResultVar),
-      expressionResultVar: expressionResultVar,
-      resultVar:           resultVar
-    }
-  );
-};
-
-PEG.Grammar.ZeroOrMore.prototype.compile = function(resultVar) {
-  var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
-
-  return PEG.Compiler.formatCode(
-    "var ${resultVar} = [];",
-    "${expressionCode}",
-    "while (${expressionResultVar} !== null) {",
-    "  ${resultVar}.push(${expressionResultVar});",
-    "  ${expressionCode}",
-    "}",
-    {
-      expressionCode:      this.expression.compile(expressionResultVar),
-      expressionResultVar: expressionResultVar,
-      resultVar:           resultVar
-    }
-  );
-};
-
-PEG.Grammar.OneOrMore.prototype.compile = function(resultVar) {
-  var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
-
-  return PEG.Compiler.formatCode(
-    "${expressionCode}",
-    "if (${expressionResultVar} !== null) {",
-    "  var ${resultVar} = [];",
-    "  while (${expressionResultVar} !== null) {",
-    "    ${resultVar}.push(${expressionResultVar});",
-    "    ${expressionCode}",
-    "  }",
-    "} else {",
-    "  var ${resultVar} = null;",
-    "}",
-    {
-      expressionCode:      this.expression.compile(expressionResultVar),
-      expressionResultVar: expressionResultVar,
-      resultVar:           resultVar
-    }
-  );
-};
-
-PEG.Grammar.Action.prototype.compile = function(resultVar) {
-  /*
-   * In case of sequences, we splat their elements into function arguments one
-   * by one. Example:
-   *
-   *   start: "a" "b" "c" { alert(arguments.length) }     // => 3
-   *
-   * This behavior is reflected in this function.
-   */
-
-  var expressionResultVar = PEG.Compiler.generateUniqueIdentifier("result");
-
-  if (this.expression.type === "sequence") {
-    var params = PEG.ArrayUtils.map(
-      PEG.ArrayUtils.range(1, this.expression.elements.length + 1),
-      function(n) { return "$" + n; }
-    ).join(", ");
-
-    var invocationCode = PEG.Compiler.formatCode(
-      "(function(${params}) { ${action} }).apply(null, ${expressionResultVar})",
-      {
-        params:              params,
-        action:              this.action,
-        expressionResultVar: expressionResultVar
-      }
-    );
-  } else {
-    var invocationCode = PEG.Compiler.formatCode(
-      "(function($1) { ${action} })(${expressionResultVar})",
-      {
-        action:              this.action,
-        expressionResultVar: expressionResultVar
-      }
-    );
-  }
-
-  return PEG.Compiler.formatCode(
-    "${expressionCode}",
-    "var ${resultVar} = ${expressionResultVar} !== null",
-    "  ? ${invocationCode}",
-    "  : null;",
-    {
-      expressionCode:      this.expression.compile(expressionResultVar),
-      expressionResultVar: expressionResultVar,
-      invocationCode:      invocationCode,
-      resultVar:           resultVar
-    }
-  );
-};
-
-PEG.Grammar.RuleRef.prototype.compile = function(resultVar) {
-  return PEG.Compiler.formatCode(
-    "var ${resultVar} = this.${ruleMethod}(context);",
-    {
-      ruleMethod: "_parse_" + this.name,
-      resultVar:  resultVar
-    }
-  );
-};
-
-PEG.Grammar.Literal.prototype.compile = function(resultVar) {
-  return PEG.Compiler.formatCode(
-    "if (this._input.substr(this._pos, ${length}) === ${value|string}) {",
-    "  var ${resultVar} = ${value|string};",
-    "  this._pos += ${length};",
-    "} else {",
-    "  var ${resultVar} = null;",
-    "  if (context.reportMatchFailures) {",
-    "    this._matchFailed(this._quoteString(${value|string}));",
-    "  }",
-    "}",
-    {
-      value:     this.value,
-      length:    this.value.length,
-      resultVar: resultVar
-    }
-  );
-};
-
-PEG.Grammar.Any.prototype.compile = function(resultVar) {
-  return PEG.Compiler.formatCode(
-    "if (this._input.length > this._pos) {",
-    "  var ${resultVar} = this._input.charAt(this._pos);",
-    "  this._pos++;",
-    "} else {",
-    "  var ${resultVar} = null;",
-    "  if (context.reportMatchFailures) {",
-    "    this._matchFailed('any character');",
-    "  }",
-    "}",
-    { resultVar: resultVar }
-  );
-};
-
-
-PEG.Grammar.Class.prototype.compile = function(resultVar) {
-  /*
-   * Stupid IE considers regexps /[]/ and /[^]/ syntactically invalid, so we
-   * translate them into euqivalents it can handle.
-   */
-  if (this.characters === "") {
-    var regexp = "/^(?!)/";
-  } else if (this.characters === "^") {
-    var regexp = "/^[\\S\\s]/";
-  } else {
-    var regexp = "/^[" + this.characters + "]/";
-  }
-
-  return PEG.Compiler.formatCode(
-    "if (this._input.substr(this._pos).match(${regexp}) !== null) {",
-    "  var ${resultVar} = this._input.charAt(this._pos);",
-    "  this._pos++;",
-    "} else {",
-    "  var ${resultVar} = null;",
-    "  if (context.reportMatchFailures) {",
-    "    this._matchFailed('[' + ${characters|string} + ']');",
-    "  }",
-    "}",
-    {
-      characters: this.characters,
-      regexp:     regexp,
-      resultVar:  resultVar
-    }
-  );
-};
-
 })();