pegjs/lib/compiler/passes/generate-javascript.js

var utils = require("../../utils"),
    op    = require("../opcodes");

/* Generates parser JavaScript code. */
module.exports = function(ast, options) {
  /* These only indent non-empty lines to avoid trailing whitespace. */
  function indent2(code)  { return code.replace(/^(.+)$/gm, '  $1');         }
  function indent4(code)  { return code.replace(/^(.+)$/gm, '    $1');       }
  function indent8(code)  { return code.replace(/^(.+)$/gm, '        $1');   }
  function indent10(code) { return code.replace(/^(.+)$/gm, '          $1'); }

  function generateTables() {
    if (options.optimize === "size") {
      return [
        'peg$consts = [',
           indent2(ast.consts.join(',\n')),
        '],',
        '',
        'peg$bytecode = [',
           indent2(utils.map(
             ast.rules,
             function(rule) {
               return 'peg$decode('
                     + utils.quote(utils.map(
                         rule.bytecode,
                         function(b) { return String.fromCharCode(b + 32); }
                       ).join(''))
                     + ')';
             }
           ).join(',\n')),
        '],'
      ].join('\n');
    } else {
      return utils.map(
        ast.consts,
        function(c, i) { return 'peg$c' + i + ' = ' + c + ','; }
      ).join('\n');
    }
  }

  function generateCacheHeader(ruleIndexCode) {
    return [
      'var key    = peg$currPos * ' + ast.rules.length + ' + ' + ruleIndexCode + ',',
      '    cached = peg$cache[key];',
      '',
      'if (cached) {',
      '  peg$currPos = cached.nextPos;',
      '  return cached.result;',
      '}',
      ''
    ].join('\n');
  }

  function generateCacheFooter(resultCode) {
    return [
      '',
      'peg$cache[key] = { nextPos: peg$currPos, result: ' + resultCode + ' };'
    ].join('\n');
  }

  function generateInterpreter() {
    var parts = [];

    function generateCondition(cond, argsLength) {
      var baseLength      = argsLength + 3,
          thenLengthCode = 'bc[ip + ' + (baseLength - 2) + ']',
          elseLengthCode = 'bc[ip + ' + (baseLength - 1) + ']';

      return [
        'ends.push(end);',
        'ips.push(ip + ' + baseLength + ' + ' + thenLengthCode + ' + ' + elseLengthCode + ');',
        '',
        'if (' + cond + ') {',
        '  end = ip + ' + baseLength + ' + ' + thenLengthCode + ';',
        '  ip += ' + baseLength + ';',
        '} else {',
        '  end = ip + ' + baseLength + ' + ' + thenLengthCode + ' + ' + elseLengthCode + ';',
        '  ip += ' + baseLength + ' + ' + thenLengthCode + ';',
        '}',
        '',
        'break;'
      ].join('\n');
    }

    function generateLoop(cond) {
      var baseLength     = 2,
          bodyLengthCode = 'bc[ip + ' + (baseLength - 1) + ']';

      return [
        'if (' + cond + ') {',
        '  ends.push(end);',
        '  ips.push(ip);',
        '',
        '  end = ip + ' + baseLength + ' + ' + bodyLengthCode + ';',
        '  ip += ' + baseLength + ';',
        '} else {',
        '  ip += ' + baseLength + ' + ' + bodyLengthCode + ';',
        '}',
        '',
        'break;'
      ].join('\n');
    }

    function generateCall() {
      var baseLength       = 4,
          paramsLengthCode = 'bc[ip + ' + (baseLength - 1) + ']';

      return [
        'params = bc.slice(ip + ' + baseLength + ', ip + ' + baseLength + ' + ' + paramsLengthCode + ');',
        'for (i = 0; i < ' + paramsLengthCode + '; i++) {',
        '  params[i] = stack[stack.length - 1 - params[i]];',
        '}',
        '',
        'stack.splice(',
        '  stack.length - bc[ip + 2],',
        '  bc[ip + 2],',
        '  peg$consts[bc[ip + 1]].apply(null, params)',
        ');',
        '',
        'ip += ' + baseLength + ' + ' + paramsLengthCode + ';',
        'break;'
      ].join('\n');
    }

    parts.push([
      'function peg$decode(s) {',
      '  var bc = new Array(s.length), i;',
      '',
      '  for (i = 0; i < s.length; i++) {',
      '    bc[i] = s.charCodeAt(i) - 32;',
      '  }',
      '',
      '  return bc;',
      '}',
      '',
      'function peg$parseRule(index) {',
      '  var bc    = peg$bytecode[index],',
      '      ip    = 0,',
      '      ips   = [],',
      '      end   = bc.length,',
      '      ends  = [],',
      '      stack = [],',
      '      params, i;',
      ''
    ].join('\n'));

    if (options.cache) {
      parts.push(indent2(generateCacheHeader('index')));
    }

    parts.push([
      '  function protect(object) {',
      '    return Object.prototype.toString.apply(object) === "[object Array]" ? [] : object;',
      '  }',
      '',
      /*
       * The point of the outer loop and the |ips| & |ends| stacks is to avoid
       * recursive calls for interpreting parts of bytecode. In other words, we
       * implement the |interpret| operation of the abstract machine without
       * function calls. Such calls would likely slow the parser down and more
       * importantly cause stack overflows for complex grammars.
       */
      '  while (true) {',
      '    while (ip < end) {',
      '      switch (bc[ip]) {',
      '        case ' + op.PUSH + ':',             // PUSH c
      /*
       * Hack: One of the constants can be an empty array. It needs to be cloned
       * because it can be modified later on the stack by |APPEND|.
       */
      '          stack.push(protect(peg$consts[bc[ip + 1]]));',
      '          ip += 2;',
      '          break;',
      '',
      '        case ' + op.PUSH_CURR_POS + ':',    // PUSH_CURR_POS
      '          stack.push(peg$currPos);',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.POP + ':',              // POP
      '          stack.pop();',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.POP_CURR_POS + ':',     // POP_CURR_POS
      '          peg$currPos = stack.pop();',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.POP_N + ':',            // POP_N n
      '          stack.length -= bc[ip + 1];',
      '          ip += 2;',
      '          break;',
      '',
      '        case ' + op.NIP + ':',              // NIP
      '          stack.splice(-2, 1);',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.NIP_CURR_POS + ':',     // NIP_CURR_POS
      '          peg$currPos = stack.splice(-2, 1)[0];',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.APPEND + ':',           // APPEND
      '          stack[stack.length - 2].push(stack.pop());',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.WRAP + ':',             // WRAP n
      '          stack.push(stack.splice(stack.length - bc[ip + 1]));',
      '          ip += 2;',
      '          break;',
      '',
      '        case ' + op.TEXT + ':',             // TEXT
      '          stack.pop();',
      '          stack.push(input.substring(stack[stack.length - 1], peg$currPos));',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.IF + ':',               // IF t, f
                 indent10(generateCondition('stack[stack.length - 1]', 0)),
      '',
      '        case ' + op.IF_ERROR + ':',         // IF_ERROR t, f
                 indent10(generateCondition(
                   'stack[stack.length - 1] === null',
                   0
                 )),
      '',
      '        case ' + op.IF_NOT_ERROR + ':',     // IF_NOT_ERROR t, f
                 indent10(
                   generateCondition('stack[stack.length - 1] !== null',
                   0
                 )),
      '',
      '        case ' + op.WHILE_NOT_ERROR + ':',  // WHILE_NOT_ERROR b
                 indent10(generateLoop('stack[stack.length - 1] !== null')),
      '',
      '        case ' + op.MATCH_ANY + ':',        // MATCH_ANY a, f, ...
                 indent10(generateCondition('input.length > peg$currPos', 0)),
      '',
      '        case ' + op.MATCH_STRING + ':',     // MATCH_STRING s, a, f, ...
                 indent10(generateCondition(
                   'input.substr(peg$currPos, peg$consts[bc[ip + 1]].length) === peg$consts[bc[ip + 1]]',
                   1
                 )),
      '',
      '        case ' + op.MATCH_STRING_IC + ':',  // MATCH_STRING_IC s, a, f, ...
                 indent10(generateCondition(
                   'input.substr(peg$currPos, peg$consts[bc[ip + 1]].length).toLowerCase() === peg$consts[bc[ip + 1]]',
                   1
                 )),
      '',
      '        case ' + op.MATCH_REGEXP + ':',     // MATCH_REGEXP r, a, f, ...
                 indent10(generateCondition(
                   'peg$consts[bc[ip + 1]].test(input.charAt(peg$currPos))',
                   1
                 )),
      '',
      '        case ' + op.ACCEPT_N + ':',         // ACCEPT_N n
      '          stack.push(input.substr(peg$currPos, bc[ip + 1]));',
      '          peg$currPos += bc[ip + 1];',
      '          ip += 2;',
      '          break;',
      '',
      '        case ' + op.ACCEPT_STRING + ':',    // ACCEPT_STRING s
      '          stack.push(peg$consts[bc[ip + 1]]);',
      '          peg$currPos += peg$consts[bc[ip + 1]].length;',
      '          ip += 2;',
      '          break;',
      '',
      '        case ' + op.FAIL + ':',             // FAIL e
      '          stack.push(null);',
      '          if (peg$silentFails === 0) {',
      '            peg$fail(peg$consts[bc[ip + 1]]);',
      '          }',
      '          ip += 2;',
      '          break;',
      '',
      '        case ' + op.REPORT_SAVED_POS + ':', // REPORT_SAVED_POS p
      '          peg$reportedPos = stack[stack.length - 1 - bc[ip + 1]];',
      '          ip += 2;',
      '          break;',
      '',
      '        case ' + op.REPORT_CURR_POS + ':',  // REPORT_CURR_POS
      '          peg$reportedPos = peg$currPos;',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.CALL + ':',             // CALL f, n, pc, p1, p2, ..., pN
                 indent10(generateCall()),
      '',
      '        case ' + op.RULE + ':',             // RULE r
      '          stack.push(peg$parseRule(bc[ip + 1]));',
      '          ip += 2;',
      '          break;',
      '',
      '        case ' + op.SILENT_FAILS_ON + ':',  // SILENT_FAILS_ON
      '          peg$silentFails++;',
      '          ip++;',
      '          break;',
      '',
      '        case ' + op.SILENT_FAILS_OFF + ':', // SILENT_FAILS_OFF
      '          peg$silentFails--;',
      '          ip++;',
      '          break;',
      '',
      '        default:',
      '          throw new Error("Invalid opcode: " + bc[ip] + ".");',
      '      }',
      '    }',
      '',
      '    if (ends.length > 0) {',
      '      end = ends.pop();',
      '      ip = ips.pop();',
      '    } else {',
      '      break;',
      '    }',
      '  }'
    ].join('\n'));

    if (options.cache) {
      parts.push(indent2(generateCacheFooter('stack[0]')));
    }

    parts.push([
      '',
      '  return stack[0];',
      '}'
    ].join('\n'));

    return parts.join('\n');
  }

  function generateRuleFunction(rule) {
    var parts = [], code;

    function c(i) { return "peg$c" + i; } // |consts[i]| of the abstract machine
    function s(i) { return "s"     + i; } // |stack[i]| of the abstract machine

    var stack = {
          sp:    -1,
          maxSp: -1,

          push: function(exprCode) {
            var code = s(++this.sp) + ' = ' + exprCode + ';';

            if (this.sp > this.maxSp) { this.maxSp = this.sp; }

            return code;
          },

          pop: function() {
            var n, values;

            if (arguments.length === 0) {
              return s(this.sp--);
            } else {
              n = arguments[0];
              values = utils.map(utils.range(this.sp - n + 1, this.sp + 1), s);
              this.sp -= n;

              return values;
            }
          },

          top: function() {
            return s(this.sp);
          },

          index: function(i) {
            return s(this.sp - i);
          }
        };

    function compile(bc) {
      var ip    = 0,
          end   = bc.length,
          parts = [],
          value;

      function compileCondition(cond, argCount) {
        var baseLength = argCount + 3,
            thenLength = bc[ip + baseLength - 2],
            elseLength = bc[ip + baseLength - 1],
            baseSp     = stack.sp,
            thenCode, elseCode;

        ip += baseLength;
        thenCode = compile(bc.slice(ip, ip + thenLength));
        ip += thenLength;
        if (elseLength > 0) {
          stack.sp = baseSp;
          elseCode = compile(bc.slice(ip, ip + elseLength));
          ip += elseLength;
        }

        parts.push('if (' + cond + ') {');
        parts.push(indent2(thenCode));
        if (elseLength > 0) {
          parts.push('} else {');
          parts.push(indent2(elseCode));
        }
        parts.push('}');
      }

      function compileLoop(cond) {
        var baseLength = 2,
            bodyLength = bc[ip + baseLength - 1],
            bodyCode;

        ip += baseLength;
        bodyCode = compile(bc.slice(ip, ip + bodyLength));
        ip += bodyLength;

        parts.push('while (' + cond + ') {');
        parts.push(indent2(bodyCode));
        parts.push('}');
      }

      function compileCall(cond) {
        var baseLength   = 4,
            paramsLength = bc[ip + baseLength - 1];

        var value = c(bc[ip + 1]) + '('
              + utils.map(
                  bc.slice(ip + baseLength, ip + baseLength + paramsLength),
                  stackIndex
                )
              + ')';
        stack.pop(bc[ip + 2]);
        parts.push(stack.push(value));
        ip += baseLength + paramsLength;
      }

      /*
       * Extracted into a function just to silence JSHint complaining about
       * creating functions in a loop.
       */
      function stackIndex(p) {
        return stack.index(p);
      }

      while (ip < end) {
        switch (bc[ip]) {
          case op.PUSH:             // PUSH c
            /*
             * Hack: One of the constants can be an empty array. It needs to be
             * handled specially because it can be modified later on the stack
             * by |APPEND|.
             */
            parts.push(
              stack.push(ast.consts[bc[ip + 1]] === "[]" ? "[]" : c(bc[ip + 1]))
            );
            ip += 2;
            break;

          case op.PUSH_CURR_POS:    // PUSH_CURR_POS
            parts.push(stack.push('peg$currPos'));
            ip++;
            break;

          case op.POP:              // POP
            stack.pop();
            ip++;
            break;

          case op.POP_CURR_POS:     // POP_CURR_POS
            parts.push('peg$currPos = ' + stack.pop() + ';');
            ip++;
            break;

          case op.POP_N:            // POP_N n
            stack.pop(bc[ip + 1]);
            ip += 2;
            break;

          case op.NIP:              // NIP
            value = stack.pop();
            stack.pop();
            parts.push(stack.push(value));
            ip++;
            break;

          case op.NIP_CURR_POS:     // NIP_CURR_POS
            value = stack.pop();
            parts.push('peg$currPos = ' + stack.pop() + ';');
            parts.push(stack.push(value));
            ip++;
            break;

          case op.APPEND:           // APPEND
            value = stack.pop();
            parts.push(stack.top() + '.push(' + value + ');');
            ip++;
            break;

          case op.WRAP:             // WRAP n
            parts.push(
              stack.push('[' + stack.pop(bc[ip + 1]).join(', ') + ']')
            );
            ip += 2;
            break;

          case op.TEXT:             // TEXT
            stack.pop();
            parts.push(
              stack.push('input.substring(' + stack.top() + ', peg$currPos)')
            );
            ip++;
            break;

          case op.IF:               // IF t, f
            compileCondition(stack.top(), 0);
            break;

          case op.IF_ERROR:         // IF_ERROR t, f
            compileCondition(stack.top() + ' === null', 0);
            break;

          case op.IF_NOT_ERROR:     // IF_NOT_ERROR t, f
            compileCondition(stack.top() + ' !== null', 0);
            break;

          case op.WHILE_NOT_ERROR:  // WHILE_NOT_ERROR b
            compileLoop(stack.top() + ' !== null', 0);
            break;

          case op.MATCH_ANY:        // MATCH_ANY a, f, ...
            compileCondition('input.length > peg$currPos', 0);
            break;

          case op.MATCH_STRING:     // MATCH_STRING s, a, f, ...
            compileCondition(
              eval(ast.consts[bc[ip + 1]]).length > 1
                ? 'input.substr(peg$currPos, '
                    + eval(ast.consts[bc[ip + 1]]).length
                    + ') === '
                    + c(bc[ip + 1])
                : 'input.charCodeAt(peg$currPos) === '
                    + eval(ast.consts[bc[ip + 1]]).charCodeAt(0),
              1
            );
            break;

          case op.MATCH_STRING_IC:  // MATCH_STRING_IC s, a, f, ...
            compileCondition(
              'input.substr(peg$currPos, '
                + ast.consts[bc[ip + 1]].length
                + ').toLowerCase() === '
                + c(bc[ip + 1]),
              1
            );
            break;

          case op.MATCH_REGEXP:     // MATCH_REGEXP r, a, f, ...
            compileCondition(
              c(bc[ip + 1]) + '.test(input.charAt(peg$currPos))',
              1
            );
            break;

          case op.ACCEPT_N:         // ACCEPT_N n
            parts.push(stack.push(
              bc[ip + 1] > 1
                ? 'input.substr(peg$currPos, ' + bc[ip + 1] + ')'
                : 'input.charAt(peg$currPos)'
            ));
            parts.push(
              bc[ip + 1] > 1
                ? 'peg$currPos += ' + bc[ip + 1] + ';'
                : 'peg$currPos++;'
            );
            ip += 2;
            break;

          case op.ACCEPT_STRING:    // ACCEPT_STRING s
            parts.push(stack.push(c(bc[ip + 1])));
            parts.push(
              eval(ast.consts[bc[ip + 1]]).length > 1
                ? 'peg$currPos += ' + eval(ast.consts[bc[ip + 1]]).length + ';'
                : 'peg$currPos++;'
            );
            ip += 2;
            break;

          case op.FAIL:             // FAIL e
            parts.push(stack.push('null'));
            parts.push('if (peg$silentFails === 0) { peg$fail(' + c(bc[ip + 1]) + '); }');
            ip += 2;
            break;

          case op.REPORT_SAVED_POS: // REPORT_SAVED_POS p
            parts.push('peg$reportedPos = ' + stack.index(bc[ip + 1]) + ';');
            ip += 2;
            break;

          case op.REPORT_CURR_POS:  // REPORT_CURR_POS
            parts.push('peg$reportedPos = peg$currPos;');
            ip++;
            break;

          case op.CALL:             // CALL f, n, pc, p1, p2, ..., pN
            compileCall();
            break;

          case op.RULE:             // RULE r
            parts.push(stack.push("peg$parse" + ast.rules[bc[ip + 1]].name + "()"));
            ip += 2;
            break;

          case op.SILENT_FAILS_ON:  // SILENT_FAILS_ON
            parts.push('peg$silentFails++;');
            ip++;
            break;

          case op.SILENT_FAILS_OFF: // SILENT_FAILS_OFF
            parts.push('peg$silentFails--;');
            ip++;
            break;

          default:
            throw new Error("Invalid opcode: " + bc[ip] + ".");
        }
      }

      return parts.join('\n');
    }

    code = compile(rule.bytecode);

    parts.push([
      'function peg$parse' + rule.name + '() {',
      '  var ' + utils.map(utils.range(0, stack.maxSp + 1), s).join(', ') + ';',
      ''
    ].join('\n'));

    if (options.cache) {
      parts.push(indent2(
        generateCacheHeader(utils.indexOfRuleByName(ast, rule.name))
      ));
    }

    parts.push(indent2(code));

    if (options.cache) {
      parts.push(indent2(generateCacheFooter('s0')));
    }

    parts.push([
      '',
      '  return s0;',
      '}'
    ].join('\n'));

    return parts.join('\n');
  }

  var parts = [],
      startRuleIndices,   startRuleIndex,
      startRuleFunctions, startRuleFunction;

  parts.push([
    '(function() {',
    '  /*',
    '   * Generated by PEG.js 0.7.0.',
    '   *',
    '   * http://pegjs.majda.cz/',
    '   */',
    '',
    '  function peg$subclass(child, parent) {',
    '    function ctor() { this.constructor = child; }',
    '    ctor.prototype = parent.prototype;',
    '    child.prototype = new ctor();',
    '  }',
    '',
    '  function SyntaxError(expected, found, offset, line, column) {',
    '    function buildMessage(expected, found) {',
    '      function stringEscape(s) {',
    '        function hex(ch) { return ch.charCodeAt(0).toString(16).toUpperCase(); }',
    '',
    /*
     * ECMA-262, 5th ed., 7.8.4: All characters may appear literally in a string
     * literal except for the closing quote character, backslash, carriage
     * return, line separator, paragraph separator, and line feed. Any character
     * may appear in the form of an escape sequence.
     *
     * For portability, we also escape escape all control and non-ASCII
     * characters. Note that "\0" and "\v" escape sequences are not used because
     * JSHint does not like the first and IE the second.
     */
    '        return s',
    '          .replace(/\\\\/g,   \'\\\\\\\\\')', // backslash
    '          .replace(/"/g,    \'\\\\"\')',      // closing double quote
    '          .replace(/\\x08/g, \'\\\\b\')',     // backspace
    '          .replace(/\\t/g,   \'\\\\t\')',     // horizontal tab
    '          .replace(/\\n/g,   \'\\\\n\')',     // line feed
    '          .replace(/\\f/g,   \'\\\\f\')',     // form feed
    '          .replace(/\\r/g,   \'\\\\r\')',     // carriage return
    '          .replace(/[\\x00-\\x07\\x0B\\x0E\\x0F]/g, function(ch) { return \'\\\\x0\' + hex(ch); })',
    '          .replace(/[\\x10-\\x1F\\x80-\\xFF]/g,    function(ch) { return \'\\\\x\'  + hex(ch); })',
    '          .replace(/[\\u0180-\\u0FFF]/g,         function(ch) { return \'\\\\u0\' + hex(ch); })',
    '          .replace(/[\\u1080-\\uFFFF]/g,         function(ch) { return \'\\\\u\'  + hex(ch); });',
    '      }',
    '',
    '      var expectedDesc, foundDesc;',
    '',
    '      switch (expected.length) {',
    '        case 0:',
    '          expectedDesc = "end of input";',
    '          break;',
    '',
    '        case 1:',
    '          expectedDesc = expected[0];',
    '          break;',
    '',
    '        default:',
    '          expectedDesc = expected.slice(0, -1).join(", ")',
    '            + " or "',
    '            + expected[expected.length - 1];',
    '      }',
    '',
    '      foundDesc = found ? "\\"" + stringEscape(found) + "\\"" : "end of input";',
    '',
    '      return "Expected " + expectedDesc + " but " + foundDesc + " found.";',
    '    }',
    '',
    '    this.expected = expected;',
    '    this.found    = found;',
    '    this.offset   = offset;',
    '    this.line     = line;',
    '    this.column   = column;',
    '',
    '    this.name     = "SyntaxError";',
    '    this.message  = buildMessage(expected, found);',
    '  }',
    '',
    '  peg$subclass(SyntaxError, Error);',
    '',
    '  function parse(input) {',
    '    var options = arguments.length > 1 ? arguments[1] : {},',
    ''
  ].join('\n'));

  if (options.optimize === "size") {
    startRuleIndices = '{ '
                     + utils.map(
                         options.allowedStartRules,
                         function(r) { return r + ': ' + utils.indexOfRuleByName(ast, r); }
                       ).join(', ')
                     + ' }';
    startRuleIndex = utils.indexOfRuleByName(ast, options.allowedStartRules[0]);

    parts.push([
      '        peg$startRuleIndices = ' + startRuleIndices + ',',
      '        peg$startRuleIndex   = ' + startRuleIndex + ','
    ].join('\n'));
  } else {
    startRuleFunctions = '{ '
                     + utils.map(
                         options.allowedStartRules,
                         function(r) { return r + ': peg$parse' + r; }
                       ).join(', ')
                     + ' }';
    startRuleFunction = 'peg$parse' + options.allowedStartRules[0];

    parts.push([
      '        peg$startRuleFunctions = ' + startRuleFunctions + ',',
      '        peg$startRuleFunction  = ' + startRuleFunction + ','
    ].join('\n'));
  }

  parts.push('');

  parts.push(indent8(generateTables()));

  parts.push([
    '',
    '        peg$currPos          = 0,',
    '        peg$reportedPos      = 0,',
    '        peg$cachedPos        = 0,',
    '        peg$cachedPosDetails = { line: 1, column: 1, seenCR: false },',
    '        peg$maxFailPos       = 0,',
    '        peg$maxFailExpected  = [],',
    '        peg$silentFails      = 0,', // 0 = report failures, > 0 = silence failures
    ''
  ].join('\n'));

  if (options.cache) {
    parts.push('        peg$cache = {},');
  }

  parts.push([
    '        peg$result;',
    ''
  ].join('\n'));

  if (options.optimize === "size") {
    parts.push([
      '    if ("startRule" in options) {',
      '      if (!(options.startRule in peg$startRuleIndices)) {',
      '        throw new Error("Can\'t start parsing from rule \\"" + options.startRule + "\\".");',
      '      }',
      '',
      '      peg$startRuleIndex = peg$startRuleIndices[options.startRule];',
      '    }'
    ].join('\n'));
  } else {
    parts.push([
      '    if ("startRule" in options) {',
      '      if (!(options.startRule in peg$startRuleFunctions)) {',
      '        throw new Error("Can\'t start parsing from rule \\"" + options.startRule + "\\".");',
      '      }',
      '',
      '      peg$startRuleFunction = peg$startRuleFunctions[options.startRule];',
      '    }'
    ].join('\n'));
  }

  parts.push([
    '',
    '    function text() {',
    '      return input.substring(peg$reportedPos, peg$currPos);',
    '    }',
    '',
    '    function offset() {',
    '      return peg$reportedPos;',
    '    }',
    '',
    '    function line() {',
    '      return peg$computePosDetails(peg$reportedPos).line;',
    '    }',
    '',
    '    function column() {',
    '      return peg$computePosDetails(peg$reportedPos).column;',
    '    }',
    '',
    '    function peg$computePosDetails(pos) {',
    '      function advance(details, pos) {',
    '        var p, ch;',
    '',
    '        for (p = 0; p < pos; p++) {',
    '          ch = input.charAt(p);',
    '          if (ch === "\\n") {',
    '            if (!details.seenCR) { details.line++; }',
    '            details.column = 1;',
    '            details.seenCR = false;',
    '          } else if (ch === "\\r" || ch === "\\u2028" || ch === "\\u2029") {',
    '            details.line++;',
    '            details.column = 1;',
    '            details.seenCR = true;',
    '          } else {',
    '            details.column++;',
    '            details.seenCR = false;',
    '          }',
    '        }',
    '      }',
    '',
    '      if (peg$cachedPos !== pos) {',
    '        if (peg$cachedPos > pos) {',
    '          peg$cachedPos = 0;',
    '          peg$cachedPosDetails = { line: 1, column: 1, seenCR: false };',
    '        }',
    '        peg$cachedPos = pos;',
    '        advance(peg$cachedPosDetails, peg$cachedPos);',
    '      }',
    '',
    '      return peg$cachedPosDetails;',
    '    }',
    '',
    '    function peg$fail(expected) {',
    '      if (peg$currPos < peg$maxFailPos) { return; }',
    '',
    '      if (peg$currPos > peg$maxFailPos) {',
    '        peg$maxFailPos = peg$currPos;',
    '        peg$maxFailExpected = [];',
    '      }',
    '',
    '      peg$maxFailExpected.push(expected);',
    '    }',
    '',
    '    function peg$cleanupExpected(expected) {',
    '      var i;',
    '',
    '      expected.sort();',
    '',
    '      for (i = 1; i < expected.length; i++) {',
    '        if (expected[i - 1] === expected[i]) {',
    '          expected.splice(i, 1);',
    '        }',
    '      }',
    '    }',
    ''
  ].join('\n'));

  if (options.optimize === "size") {
    parts.push(indent4(generateInterpreter()));
    parts.push('');
  } else {
    utils.each(ast.rules, function(rule) {
      parts.push(indent4(generateRuleFunction(rule)));
      parts.push('');
    });
  }

  if (ast.initializer) {
    parts.push(indent4(ast.initializer.code));
    parts.push('');
  }

  if (options.optimize === "size") {
    parts.push('    peg$result = peg$parseRule(peg$startRuleIndex);');
  } else {
    parts.push('    peg$result = peg$startRuleFunction();');
  }

  parts.push([
    '',
    '    if (peg$result !== null && peg$currPos === input.length) {',
    '      return peg$result;',
    '    } else {',
    '      peg$cleanupExpected(peg$maxFailExpected);',
    '      peg$reportedPos = Math.max(peg$currPos, peg$maxFailPos);',
    '',
    '      throw new SyntaxError(',
    '        peg$maxFailExpected,',
    '        peg$reportedPos < input.length ? input.charAt(peg$reportedPos) : null,',
    '        peg$reportedPos,',
    '        peg$computePosDetails(peg$reportedPos).line,',
    '        peg$computePosDetails(peg$reportedPos).column',
    '      );',
    '    }',
    '  }',
    '',
    '  return {',
    '    SyntaxError: SyntaxError,',
    '    parse      : parse',
    '  };',
    '})()'
  ].join('\n'));

  ast.code = parts.join('\n');
};