/**
 * @fileoverview
 * some functions for browser-side pretty printing of code contained in html.
 * <p>
 *
 * For a fairly comprehensive set of languages see the
 * <a href="http://google-code-prettify.googlecode.com/svn/trunk/README.html#langs">README</a>
 * file that came with this source. At a minimum, the lexer should work on a
 * number of languages including C and friends, Java, Python, Bash, SQL, HTML,
 * XML, CSS, Javascript, and Makefiles. It works passably on Ruby, PHP and Awk
 * and a subset of Perl, but, because of commenting conventions, doesn't work on
 * Smalltalk, Lisp-like, or CAML-like languages without an explicit lang class.
 * <p>
 * Usage: <ol>
 * <li> include this source file in an html page via
 * {@code <script type="text/javascript" src="/path/to/prettify.js"></script>}
 * <li> define style rules. See the example page for examples.
 * <li> mark the {@code <pre>} and {@code <code>} tags in your source with
 * {@code class=prettyprint.}
 * You can also use the (html deprecated) {@code <xmp>} tag, but the pretty
 * printer needs to do more substantial DOM manipulations to support that, so
 * some css styles may not be preserved.
 * </ol>
 * That's it. I wanted to keep the API as simple as possible, so there's no
 * need to specify which language the code is in, but if you wish, you can add
 * another class to the {@code <pre>} or {@code <code>} element to specify the
 * language, as in {@code <pre class="prettyprint lang-java">}. Any class that
 * starts with "lang-" followed by a file extension, specifies the file type.
 * See the "lang-*.js" files in this directory for code that implements
 * per-language file handlers.
 * <p>
 * Change log:<br>
 * cbeust, 2006/08/22
 * <blockquote>
 * Java annotations (start with "@") are now captured as literals ("lit")
 * </blockquote>
 * @requires console
 * @overrides window
 */

// JSLint declarations
/*global console, document, navigator, setTimeout, window */

/**
 * Split {@code prettyPrint} into multiple timeouts so as not to interfere with
 * UI events. If set to {@code false}, {@code prettyPrint()} is synchronous.
 */
window['PR_SHOULD_USE_CONTINUATION'] = true;

/** the number of characters between tab columns */
window['PR_TAB_WIDTH'] = 8;

/**
 * Walks the DOM returning a properly escaped version of innerHTML.
 * 
 * @param {Node}
 *          node
 * @param {Array.
 *          <string>} out output buffer that receives chunks of HTML.
 */
window['PR_normalizedHtml']

/**
 * Contains functions for creating and registering new language handlers.
 * 
 * @type {Object}
 */
= window['PR']

/**
 * Pretty print a chunk of code.
 * 
 * @param {string}
 *          sourceCodeHtml code as html
 * @return {string} code as html, but prettier
 */
= window['prettyPrintOne']
/**
 * Find all the {@code <pre>} and {@code <code>} tags in the DOM with
 * {@code class=prettyprint} and prettify them.
 * 
 * @param {Function?}
 *          opt_whenDone if specified, called when the last entry has been
 *          finished.
 */
= window['prettyPrint'] = void 0;

/**
 * browser detection.
 * 
 * @extern
 * @returns false if not IE, otherwise the major version.
 */
window['_pr_isIE6'] = function() {
  var ieVersion = navigator && navigator.userAgent
      && navigator.userAgent.match(/\bMSIE ([678])\./);
  ieVersion = ieVersion ? +ieVersion[1] : false;
  window['_pr_isIE6'] = function() {
    return ieVersion;
  };
  return ieVersion;
};

(function() {
  // Keyword lists for various languages.
  var FLOW_CONTROL_KEYWORDS = "break continue do else for if return while ";
  var C_KEYWORDS = FLOW_CONTROL_KEYWORDS + "auto case char const default "
      + "double enum extern float goto int long register short signed sizeof "
      + "static struct switch typedef union unsigned void volatile ";
  var COMMON_KEYWORDS = C_KEYWORDS + "catch class delete false import "
      + "new operator private protected public this throw true try typeof ";
  var CPP_KEYWORDS = COMMON_KEYWORDS + "alignof align_union asm axiom bool "
      + "concept concept_map const_cast constexpr decltype "
      + "dynamic_cast explicit export friend inline late_check "
      + "mutable namespace nullptr reinterpret_cast static_assert static_cast "
      + "template typeid typename using virtual wchar_t where ";
  var JAVA_KEYWORDS = COMMON_KEYWORDS
      + "abstract boolean byte extends final finally implements import "
      + "instanceof null native package strictfp super synchronized throws "
      + "transient ";
  var CSHARP_KEYWORDS = JAVA_KEYWORDS
      + "as base by checked decimal delegate descending event "
      + "fixed foreach from group implicit in interface internal into is lock "
      + "object out override orderby params partial readonly ref sbyte sealed "
      + "stackalloc string select uint ulong unchecked unsafe ushort var ";
  var JSCRIPT_KEYWORDS = COMMON_KEYWORDS
      + "debugger eval export function get null set undefined var with "
      + "Infinity NaN ";
  var PERL_KEYWORDS = "caller delete die do dump elsif eval exit foreach for "
      + "goto if import last local my next no our print package redo require "
      + "sub undef unless until use wantarray while BEGIN END ";
  var PYTHON_KEYWORDS = FLOW_CONTROL_KEYWORDS + "and as assert class def del "
      + "elif except exec finally from global import in is lambda "
      + "nonlocal not or pass print raise try with yield " + "False True None ";
  var RUBY_KEYWORDS = FLOW_CONTROL_KEYWORDS
      + "alias and begin case class def"
      + " defined elsif end ensure false in module next nil not or redo rescue "
      + "retry self super then true undef unless until when yield BEGIN END ";
  var SH_KEYWORDS = FLOW_CONTROL_KEYWORDS + "case done elif esac eval fi "
      + "function in local set then until ";
  var ALL_KEYWORDS = (CPP_KEYWORDS + CSHARP_KEYWORDS + JSCRIPT_KEYWORDS
      + PERL_KEYWORDS + PYTHON_KEYWORDS + RUBY_KEYWORDS + SH_KEYWORDS);

  // token style names. correspond to css classes
  /** token style for a string literal */
  var PR_STRING = 'str';
  /** token style for a keyword */
  var PR_KEYWORD = 'kwd';
  /** token style for a comment */
  var PR_COMMENT = 'com';
  /** token style for a type */
  var PR_TYPE = 'typ';
  /** token style for a literal value. e.g. 1, null, true. */
  var PR_LITERAL = 'lit';
  /** token style for a punctuation string. */
  var PR_PUNCTUATION = 'pun';
  /** token style for a punctuation string. */
  var PR_PLAIN = 'pln';

  /** token style for an sgml tag. */
  var PR_TAG = 'tag';
  /** token style for a markup declaration such as a DOCTYPE. */
  var PR_DECLARATION = 'dec';
  /** token style for embedded source. */
  var PR_SOURCE = 'src';
  /** token style for an sgml attribute name. */
  var PR_ATTRIB_NAME = 'atn';
  /** token style for an sgml attribute value. */
  var PR_ATTRIB_VALUE = 'atv';

  /**
   * A class that indicates a section of markup that is not code, e.g. to allow
   * embedding of line numbers within code listings.
   */
  var PR_NOCODE = 'nocode';

  /**
   * A set of tokens that can precede a regular expression literal in
   * javascript. http://www.mozilla.org/js/language/js20/rationale/syntax.html
   * has the full list, but I've removed ones that might be problematic when
   * seen in languages that don't support regular expression literals.
   * 
   * <p>
   * Specifically, I've removed any keywords that can't precede a regexp literal
   * in a syntactically legal javascript program, and I've removed the "in"
   * keyword since it's not a keyword in many languages, and might be used as a
   * count of inches.
   * 
   * <p>
   * The link a above does not accurately describe EcmaScript rules since it
   * fails to distinguish between (a=++/b/i) and (a++/b/i) but it works very
   * well in practice.
   * 
   * @private
   */
  var REGEXP_PRECEDER_PATTERN = function() {
    var preceders = [ "!", "!=", "!==", "#", "%", "%=", "&", "&&", "&&=", "&=",
        "(", "*", "*=", /* "+", */"+=", ",", /* "-", */"-=", "->", /*
                                                                     * ".",
                                                                     * "..",
                                                                     * "...",
                                                                     * handled
                                                                     * below
                                                                     */
        "/", "/=", ":", "::", ";", "<", "<<", "<<=", "<=", "=", "==", "===",
        ">", ">=", ">>", ">>=", ">>>", ">>>=", "?", "@", "[", "^", "^=", "^^",
        "^^=", "{", "|", "|=", "||", "||=", "~" /* handles =~ and !~ */,
        "break", "case", "continue", "delete", "do", "else", "finally",
        "instanceof", "return", "throw", "try", "typeof" ];
    var pattern = '(?:^^|[+-]';
    for ( var i = 0; i < preceders.length; ++i) {
      pattern += '|' + preceders[i].replace(/([^=<>:&a-z])/g, '\\$1');
    }
    pattern += ')\\s*'; // matches at end, and matches empty string
    return pattern;
    // CAVEAT: this does not properly handle the case where a regular
    // expression immediately follows another since a regular expression may
    // have flags for case-sensitivity and the like. Having regexp tokens
    // adjacent is not valid in any language I'm aware of, so I'm punting.
    // TODO: maybe style special characters inside a regexp as punctuation.
  }();

  // Define regexps here so that the interpreter doesn't have to create an
  // object each time the function containing them is called.
  // The language spec requires a new object created even if you don't access
  // the $1 members.
  var pr_amp = /&/g;
  var pr_lt = /</g;
  var pr_gt = />/g;
  var pr_quot = /\"/g;
  /** like textToHtml but escapes double quotes to be attribute safe. */
  function attribToHtml(str) {
    return str.replace(pr_amp, '&amp;').replace(pr_lt, '&lt;').replace(pr_gt,
        '&gt;').replace(pr_quot, '&quot;');
  }

  /** escapest html special characters to html. */
  function textToHtml(str) {
    return str.replace(pr_amp, '&amp;').replace(pr_lt, '&lt;').replace(pr_gt,
        '&gt;');
  }

  var pr_ltEnt = /&lt;/g;
  var pr_gtEnt = /&gt;/g;
  var pr_aposEnt = /&apos;/g;
  var pr_quotEnt = /&quot;/g;
  var pr_ampEnt = /&amp;/g;
  var pr_nbspEnt = /&nbsp;/g;
  /** unescapes html to plain text. */
  function htmlToText(html) {
    var pos = html.indexOf('&');
    if (pos < 0) {
      return html;
    }
    // Handle numeric entities specially. We can't use functional substitution
    // since that doesn't work in older versions of Safari.
    // These should be rare since most browsers convert them to normal chars.
    for (--pos; (pos = html.indexOf('&#', pos + 1)) >= 0;) {
      var end = html.indexOf(';', pos);
      if (end >= 0) {
        var num = html.substring(pos + 3, end);
        var radix = 10;
        if (num && num.charAt(0) === 'x') {
          num = num.substring(1);
          radix = 16;
        }
        var codePoint = parseInt(num, radix);
        if (!isNaN(codePoint)) {
          html = (html.substring(0, pos) + String.fromCharCode(codePoint) + html
              .substring(end + 1));
        }
      }
    }

    return html.replace(pr_ltEnt, '<').replace(pr_gtEnt, '>').replace(
        pr_aposEnt, "'").replace(pr_quotEnt, '"').replace(pr_nbspEnt, ' ')
        .replace(pr_ampEnt, '&');
  }

  /** is the given node's innerHTML normally unescaped? */
  function isRawContent(node) {
    return 'XMP' === node.tagName;
  }

  var newlineRe = /[\r\n]/g;
  /**
   * Are newlines and adjacent spaces significant in the given node's innerHTML?
   */
  function isPreformatted(node, content) {
    // PRE means preformatted, and is a very common case, so don't create
    // unnecessary computed style objects.
    if ('PRE' === node.tagName) {
      return true;
    }
    if (!newlineRe.test(content)) {
      return true;
    } // Don't care
    var whitespace = '';
    // For disconnected nodes, IE has no currentStyle.
    if (node.currentStyle) {
      whitespace = node.currentStyle.whiteSpace;
    } else if (window.getComputedStyle) {
      // Firefox makes a best guess if node is disconnected whereas Safari
      // returns the empty string.
      whitespace = window.getComputedStyle(node, null).whiteSpace;
    }
    return !whitespace || whitespace === 'pre';
  }

  function normalizedHtml(node, out) {
    switch (node.nodeType) {
    case 1: // an element
      var name = node.tagName.toLowerCase();
      out.push('<', name);
      for ( var i = 0; i < node.attributes.length; ++i) {
        var attr = node.attributes[i];
        if (!attr.specified) {
          continue;
        }
        out.push(' ');
        normalizedHtml(attr, out);
      }
      out.push('>');
      for ( var child = node.firstChild; child; child = child.nextSibling) {
        normalizedHtml(child, out);
      }
      if (node.firstChild || !/^(?:br|link|img)$/.test(name)) {
        out.push('<\/', name, '>');
      }
      break;
    case 2: // an attribute
      out.push(node.name.toLowerCase(), '="', attribToHtml(node.value), '"');
      break;
    case 3:
    case 4: // text
      out.push(textToHtml(node.nodeValue));
      break;
    }
  }

  /**
   * Given a group of {@link RegExp}s, returns a {@code RegExp} that globally
   * matches the union o the sets o strings matched d by the input RegExp. Since
   * it matches globally, if the input strings have a start-of-input anchor
   * (/^.../), it is ignored for the purposes of unioning.
   * 
   * @param {Array.
   *          <RegExp>} regexs non multiline, non-global regexs.
   * @return {RegExp} a global regex.
   */
  function combinePrefixPatterns(regexs) {
    var capturedGroupIndex = 0;

    var needToFoldCase = false;
    var ignoreCase = false;
    for ( var i = 0, n = regexs.length; i < n; ++i) {
      var regex = regexs[i];
      if (regex.ignoreCase) {
        ignoreCase = true;
      } else if (/[a-z]/i.test(regex.source.replace(
          /\\u[0-9a-f]{4}|\\x[0-9a-f]{2}|\\[^ux]/gi, ''))) {
        needToFoldCase = true;
        ignoreCase = false;
        break;
      }
    }

    function decodeEscape(charsetPart) {
      if (charsetPart.charAt(0) !== '\\') {
        return charsetPart.charCodeAt(0);
      }
      switch (charsetPart.charAt(1)) {
      case 'b':
        return 8;
      case 't':
        return 9;
      case 'n':
        return 0xa;
      case 'v':
        return 0xb;
      case 'f':
        return 0xc;
      case 'r':
        return 0xd;
      case 'u':
      case 'x':
        return parseInt(charsetPart.substring(2), 16)
            || charsetPart.charCodeAt(1);
      case '0':
      case '1':
      case '2':
      case '3':
      case '4':
      case '5':
      case '6':
      case '7':
        return parseInt(charsetPart.substring(1), 8);
      default:
        return charsetPart.charCodeAt(1);
      }
    }

    function encodeEscape(charCode) {
      if (charCode < 0x20) {
        return (charCode < 0x10 ? '\\x0' : '\\x') + charCode.toString(16);
      }
      var ch = String.fromCharCode(charCode);
      if (ch === '\\' || ch === '-' || ch === '[' || ch === ']') {
        ch = '\\' + ch;
      }
      return ch;
    }

    function caseFoldCharset(charSet) {
      var charsetParts = charSet.substring(1, charSet.length - 1).match(
          new RegExp('\\\\u[0-9A-Fa-f]{4}' + '|\\\\x[0-9A-Fa-f]{2}'
              + '|\\\\[0-3][0-7]{0,2}' + '|\\\\[0-7]{1,2}' + '|\\\\[\\s\\S]'
              + '|-' + '|[^-\\\\]', 'g'));
      var groups = [];
      var ranges = [];
      var inverse = charsetParts[0] === '^';
      for ( var i = inverse ? 1 : 0, n = charsetParts.length; i < n; ++i) {
        var p = charsetParts[i];
        switch (p) {
        case '\\B':
        case '\\b':
        case '\\D':
        case '\\d':
        case '\\S':
        case '\\s':
        case '\\W':
        case '\\w':
          groups.push(p);
          continue;
        }
        var start = decodeEscape(p);
        var end;
        if (i + 2 < n && '-' === charsetParts[i + 1]) {
          end = decodeEscape(charsetParts[i + 2]);
          i += 2;
        } else {
          end = start;
        }
        ranges.push([ start, end ]);
        // If the range might intersect letters, then expand it.
        if (!(end < 65 || start > 122)) {
          if (!(end < 65 || start > 90)) {
            ranges.push([ Math.max(65, start) | 32, Math.min(end, 90) | 32 ]);
          }
          if (!(end < 97 || start > 122)) {
            ranges
                .push([ Math.max(97, start) & ~32, Math.min(end, 122) & ~32 ]);
          }
        }
      }

      // [[1, 10], [3, 4], [8, 12], [14, 14], [16, 16], [17, 17]]
      // -> [[1, 12], [14, 14], [16, 17]]
      ranges.sort(function(a, b) {
        return (a[0] - b[0]) || (b[1] - a[1]);
      });
      var consolidatedRanges = [];
      var lastRange = [ NaN, NaN ];
      for ( var i = 0; i < ranges.length; ++i) {
        var range = ranges[i];
        if (range[0] <= lastRange[1] + 1) {
          lastRange[1] = Math.max(lastRange[1], range[1]);
        } else {
          consolidatedRanges.push(lastRange = range);
        }
      }

      var out = [ '[' ];
      if (inverse) {
        out.push('^');
      }
      out.push.apply(out, groups);
      for ( var i = 0; i < consolidatedRanges.length; ++i) {
        var range = consolidatedRanges[i];
        out.push(encodeEscape(range[0]));
        if (range[1] > range[0]) {
          if (range[1] + 1 > range[0]) {
            out.push('-');
          }
          out.push(encodeEscape(range[1]));
        }
      }
      out.push(']');
      return out.join('');
    }

    function allowAnywhereFoldCaseAndRenumberGroups(regex) {
      // Split into character sets, escape sequences, punctuation strings
      // like ('(', '(?:', ')', '^'), and runs of characters that do not
      // include any of the above.
      var parts = regex.source.match(new RegExp('(?:'
          + '\\[(?:[^\\x5C\\x5D]|\\\\[\\s\\S])*\\]' // a character set
          + '|\\\\u[A-Fa-f0-9]{4}' // a unicode escape
          + '|\\\\x[A-Fa-f0-9]{2}' // a hex escape
          + '|\\\\[0-9]+' // a back-reference or octal escape
          + '|\\\\[^ux0-9]' // other escape sequence
          + '|\\(\\?[:!=]' // start of a non-capturing group
          + '|[\\(\\)\\^]' // start/emd of a group, or line start
          + '|[^\\x5B\\x5C\\(\\)\\^]+' // run of other characters
          + ')', 'g'));
      var n = parts.length;

      // Maps captured group numbers to the number they will occupy in
      // the output or to -1 if that has not been determined, or to
      // undefined if they need not be capturing in the output.
      var capturedGroups = [];

      // Walk over and identify back references to build the capturedGroups
      // mapping.
      for ( var i = 0, groupIndex = 0; i < n; ++i) {
        var p = parts[i];
        if (p === '(') {
          // groups are 1-indexed, so max group index is count of '('
          ++groupIndex;
        } else if ('\\' === p.charAt(0)) {
          var decimalValue = +p.substring(1);
          if (decimalValue && decimalValue <= groupIndex) {
            capturedGroups[decimalValue] = -1;
          }
        }
      }

      // Renumber groups and reduce capturing groups to non-capturing groups
      // where possible.
      for ( var i = 1; i < capturedGroups.length; ++i) {
        if (-1 === capturedGroups[i]) {
          capturedGroups[i] = ++capturedGroupIndex;
        }
      }
      for ( var i = 0, groupIndex = 0; i < n; ++i) {
        var p = parts[i];
        if (p === '(') {
          ++groupIndex;
          if (capturedGroups[groupIndex] === undefined) {
            parts[i] = '(?:';
          }
        } else if ('\\' === p.charAt(0)) {
          var decimalValue = +p.substring(1);
          if (decimalValue && decimalValue <= groupIndex) {
            parts[i] = '\\' + capturedGroups[groupIndex];
          }
        }
      }

      // Remove any prefix anchors so that the output will match anywhere.
      // ^^ really does mean an anchored match though.
      for ( var i = 0, groupIndex = 0; i < n; ++i) {
        if ('^' === parts[i] && '^' !== parts[i + 1]) {
          parts[i] = '';
        }
      }

      // Expand letters to groupts to handle mixing of case-sensitive and
      // case-insensitive patterns if necessary.
      if (regex.ignoreCase && needToFoldCase) {
        for ( var i = 0; i < n; ++i) {
          var p = parts[i];
          var ch0 = p.charAt(0);
          if (p.length >= 2 && ch0 === '[') {
            parts[i] = caseFoldCharset(p);
          } else if (ch0 !== '\\') {
            // TODO: handle letters in numeric escapes.
            parts[i] = p.replace(/[a-zA-Z]/g, function(ch) {
              var cc = ch.charCodeAt(0);
              return '[' + String.fromCharCode(cc & ~32, cc | 32) + ']';
            });
          }
        }
      }

      return parts.join('');
    }

    var rewritten = [];
    for ( var i = 0, n = regexs.length; i < n; ++i) {
      var regex = regexs[i];
      if (regex.global || regex.multiline) {
        throw new Error('' + regex);
      }
      rewritten.push('(?:' + allowAnywhereFoldCaseAndRenumberGroups(regex)
          + ')');
    }

    return new RegExp(rewritten.join('|'), ignoreCase ? 'gi' : 'g');
  }

  var PR_innerHtmlWorks = null;
  function getInnerHtml(node) {
    // inner html is hopelessly broken in Safari 2.0.4 when the content is
    // an html description of well formed XML and the containing tag is a PRE
    // tag, so we detect that case and emulate innerHTML.
    if (null === PR_innerHtmlWorks) {
      var testNode = document.createElement('PRE');
      testNode.appendChild(document
          .createTextNode('<!DOCTYPE foo PUBLIC "foo bar">\n<foo />'));
      PR_innerHtmlWorks = !/</.test(testNode.innerHTML);
    }

    if (PR_innerHtmlWorks) {
      var content = node.innerHTML;
      // XMP tags contain unescaped entities so require special handling.
      if (isRawContent(node)) {
        content = textToHtml(content);
      } else if (!isPreformatted(node, content)) {
        content = content.replace(/(<br\s*\/?>)[\r\n]+/g, '$1').replace(
            /(?:[\r\n]+[ \t]*)+/g, ' ');
      }
      return content;
    }

    var out = [];
    for ( var child = node.firstChild; child; child = child.nextSibling) {
      normalizedHtml(child, out);
    }
    return out.join('');
  }

  /**
   * returns a function that expand tabs to spaces. This function can be fed
   * successive chunks of text, and will maintain its own internal state to keep
   * track of how tabs are expanded.
   * 
   * @return {function (string) : string} a function that takes plain text and
   *         return the text with tabs expanded.
   * @private
   */
  function makeTabExpander(tabWidth) {
    var SPACES = ' ';
    var charInLine = 0;

    return function(plainText) {
      // walk over each character looking for tabs and newlines.
      // On tabs, expand them. On newlines, reset charInLine.
      // Otherwise increment charInLine
      var out = null;
      var pos = 0;
      for ( var i = 0, n = plainText.length; i < n; ++i) {
        var ch = plainText.charAt(i);

        switch (ch) {
        case '\t':
          if (!out) {
            out = [];
          }
          out.push(plainText.substring(pos, i));
          // calculate how much space we need in front of this part
          // nSpaces is the amount of padding -- the number of spaces needed
          // to move us to the next column, where columns occur at factors of
          // tabWidth.
          var nSpaces = tabWidth - (charInLine % tabWidth);
          charInLine += nSpaces;
          for (; nSpaces >= 0; nSpaces -= SPACES.length) {
            out.push(SPACES.substring(0, nSpaces));
          }
          pos = i + 1;
          break;
        case '\n':
          charInLine = 0;
          break;
        default:
          ++charInLine;
        }
      }
      if (!out) {
        return plainText;
      }
      out.push(plainText.substring(pos));
      return out.join('');
    };
  }

  var pr_chunkPattern = new RegExp('[^<]+' // A run of characters other than
                                            // '<'
      + '|<\!--[\\s\\S]*?--\>' // an HTML comment
      + '|<!\\[CDATA\\[[\\s\\S]*?\\]\\]>' // a CDATA section
      // a probable tag that should not be highlighted
      + '|<\/?[a-zA-Z](?:[^>\"\']|\'[^\']*\'|\"[^\"]*\")*>' + '|<', // A '<'
                                                                    // that does
                                                                    // not begin
                                                                    // a larger
                                                                    // chunk
  'g');
  var pr_commentPrefix = /^<\!--/;
  var pr_cdataPrefix = /^<!\[CDATA\[/;
  var pr_brPrefix = /^<br\b/i;
  var pr_tagNameRe = /^<(\/?)([a-zA-Z][a-zA-Z0-9]*)/;

  /**
   * split markup into chunks of html tags (style null) and plain text (style
   * {@link #PR_PLAIN}), converting tags which are significant for tokenization (<br>)
   * into their textual equivalent.
   * 
   * @param {string}
   *          s html where whitespace is considered significant.
   * @return {Object} source code and extracted tags.
   * @private
   */
  function extractTags(s) {
    // since the pattern has the 'g' modifier and defines no capturing groups,
    // this will return a list of all chunks which we then classify and wrap as
    // PR_Tokens
    var matches = s.match(pr_chunkPattern);
    var sourceBuf = [];
    var sourceBufLen = 0;
    var extractedTags = [];
    if (matches) {
      for ( var i = 0, n = matches.length; i < n; ++i) {
        var match = matches[i];
        if (match.length > 1 && match.charAt(0) === '<') {
          if (pr_commentPrefix.test(match)) {
            continue;
          }
          if (pr_cdataPrefix.test(match)) {
            // strip CDATA prefix and suffix. Don't unescape since it's CDATA
            sourceBuf.push(match.substring(9, match.length - 3));
            sourceBufLen += match.length - 12;
          } else if (pr_brPrefix.test(match)) {
            // <br> tags are lexically significant so convert them to text.
            // This is undone later.
            sourceBuf.push('\n');
            ++sourceBufLen;
          } else {
            if (match.indexOf(PR_NOCODE) >= 0 && isNoCodeTag(match)) {
              // A <span class="nocode"> will start a section that should be
              // ignored. Continue walking the list until we see a matching end
              // tag.
              var name = match.match(pr_tagNameRe)[2];
              var depth = 1;
              var j;
              end_tag_loop: for (j = i + 1; j < n; ++j) {
                var name2 = matches[j].match(pr_tagNameRe);
                if (name2 && name2[2] === name) {
                  if (name2[1] === '/') {
                    if (--depth === 0) {
                      break end_tag_loop;
                    }
                  } else {
                    ++depth;
                  }
                }
              }
              if (j < n) {
                extractedTags.push(sourceBufLen, matches.slice(i, j + 1).join(
                    ''));
                i = j;
              } else { // Ignore unclosed sections.
                extractedTags.push(sourceBufLen, match);
              }
            } else {
              extractedTags.push(sourceBufLen, match);
            }
          }
        } else {
          var literalText = htmlToText(match);
          sourceBuf.push(literalText);
          sourceBufLen += literalText.length;
        }
      }
    }
    return {
      source : sourceBuf.join(''),
      tags : extractedTags
    };
  }

  /** True if the given tag contains a class attribute with the nocode class. */
  function isNoCodeTag(tag) {
    return !!tag
        // First canonicalize the representation of attributes
        .replace(/\s(\w+)\s*=\s*(?:\"([^\"]*)\"|'([^\']*)'|(\S+))/g,
            ' $1="$2$3$4"')
        // Then look for the attribute we want.
        .match(/[cC][lL][aA][sS][sS]=\"[^\"]*\bnocode\b/);
  }

  /**
   * Apply the given language handler to sourceCode and add the resulting
   * decorations to out.
   * 
   * @param {number}
   *          basePos the index of sourceCode within the chunk of source whose
   *          decorations are already present on out.
   */
  function appendDecorations(basePos, sourceCode, langHandler, out) {
    if (!sourceCode) {
      return;
    }
    var job = {
      source : sourceCode,
      basePos : basePos
    };
    langHandler(job);
    out.push.apply(out, job.decorations);
  }

  /**
   * Given triples of [style, pattern, context] returns a lexing function, The
   * lexing function interprets the patterns to find token boundaries and
   * returns a decoration list of the form [index_0, style_0, index_1, style_1,
   * ..., index_n, style_n] where index_n is an index into the sourceCode, and
   * style_n is a style constant like PR_PLAIN. index_n-1 <= index_n, and
   * style_n-1 applies to all characters in sourceCode[index_n-1:index_n].
   * 
   * The stylePatterns is a list whose elements have the form [style : string,
   * pattern : RegExp, DEPRECATED, shortcut : string].
   * 
   * Style is a style constant like PR_PLAIN, or can be a string of the form
   * 'lang-FOO', where FOO is a language extension describing the language of
   * the portion of the token in $1 after pattern executes. E.g., if style is
   * 'lang-lisp', and group 1 contains the text '(hello (world))', then that
   * portion of the token will be passed to the registered lisp handler for
   * formatting. The text before and after group 1 will be restyled using this
   * decorator so decorators should take care that this doesn't result in
   * infinite recursion. For example, the HTML lexer rule for SCRIPT elements
   * looks something like ['lang-js', /<[s]cript>(.+?)<\/script>/]. This may
   * match '<script>foo()<\/script>', which would cause the current decorator
   * to be called with '<script>' which would not match the same rule since
   * group 1 must not be empty, so it would be instead styled as PR_TAG by the
   * generic tag rule. The handler registered for the 'js' extension would then
   * be called with 'foo()', and finally, the current decorator would be called
   * with '<\/script>' which would not match the original rule and so the
   * generic tag rule would identify it as a tag.
   * 
   * Pattern must only match prefixes, and if it matches a prefix, then that
   * match is considered a token with the same style.
   * 
   * Context is applied to the last non-whitespace, non-comment token
   * recognized.
   * 
   * Shortcut is an optional string of characters, any of which, if the first
   * character, gurantee that this pattern and only this pattern matches.
   * 
   * @param {Array}
   *          shortcutStylePatterns patterns that always start with a known
   *          character. Must have a shortcut string.
   * @param {Array}
   *          fallthroughStylePatterns patterns that will be tried in order if
   *          the shortcut ones fail. May have shortcuts.
   * 
   * @return {function (Object)} a function that takes source code and returns a
   *         list of decorations.
   */
  function createSimpleLexer(shortcutStylePatterns, fallthroughStylePatterns) {
    var shortcuts = {};
    var tokenizer;
    (function() {
      var allPatterns = shortcutStylePatterns.concat(fallthroughStylePatterns);
      var allRegexs = [];
      var regexKeys = {};
      for ( var i = 0, n = allPatterns.length; i < n; ++i) {
        var patternParts = allPatterns[i];
        var shortcutChars = patternParts[3];
        if (shortcutChars) {
          for ( var c = shortcutChars.length; --c >= 0;) {
            shortcuts[shortcutChars.charAt(c)] = patternParts;
          }
        }
        var regex = patternParts[1];
        var k = '' + regex;
        if (!regexKeys.hasOwnProperty(k)) {
          allRegexs.push(regex);
          regexKeys[k] = null;
        }
      }
      allRegexs.push(/[\0-\uffff]/);
      tokenizer = combinePrefixPatterns(allRegexs);
    })();

    var nPatterns = fallthroughStylePatterns.length;
    var notWs = /\S/;

    /**
     * Lexes job.source and produces an output array job.decorations of style
     * classes preceded by the position at which they start in job.source in
     * order.
     * 
     * @param {Object}
     *          job an object like {@code source: {string} sourceText plain
     *          text, basePos: {int} position of job.source in the larger chunk
     *          of sourceCode. }
     */
    var decorate = function(job) {
      var sourceCode = job.source, basePos = job.basePos;
      /**
       * Even entries are positions in source in ascending order. Odd enties are
       * style markers (e.g., PR_COMMENT) that run from that position until the
       * end.
       * 
       * @type {Array.<number|string>}
       */
      var decorations = [ basePos, PR_PLAIN ];
      var pos = 0; // index into sourceCode
      var tokens = sourceCode.match(tokenizer) || [];
      var styleCache = {};

      for ( var ti = 0, nTokens = tokens.length; ti < nTokens; ++ti) {
        var token = tokens[ti];
        var style = styleCache[token];
        var match = void 0;

        var isEmbedded;
        if (typeof style === 'string') {
          isEmbedded = false;
        } else {
          var patternParts = shortcuts[token.charAt(0)];
          if (patternParts) {
            match = token.match(patternParts[1]);
            style = patternParts[0];
          } else {
            for ( var i = 0; i < nPatterns; ++i) {
              patternParts = fallthroughStylePatterns[i];
              match = token.match(patternParts[1]);
              if (match) {
                style = patternParts[0];
                break;
              }
            }

            if (!match) { // make sure that we make progress
              style = PR_PLAIN;
            }
          }

          isEmbedded = style.length >= 5 && 'lang-' === style.substring(0, 5);
          if (isEmbedded && !(match && typeof match[1] === 'string')) {
            isEmbedded = false;
            style = PR_SOURCE;
          }

          if (!isEmbedded) {
            styleCache[token] = style;
          }
        }

        var tokenStart = pos;
        pos += token.length;

        if (!isEmbedded) {
          decorations.push(basePos + tokenStart, style);
        } else { // Treat group 1 as an embedded block of source code.
          var embeddedSource = match[1];
          var embeddedSourceStart = token.indexOf(embeddedSource);
          var embeddedSourceEnd = embeddedSourceStart + embeddedSource.length;
          if (match[2]) {
            // If embeddedSource can be blank, then it would match at the
            // beginning which would cause us to infinitely recurse on the
            // entire token, so we catch the right context in match[2].
            embeddedSourceEnd = token.length - match[2].length;
            embeddedSourceStart = embeddedSourceEnd - embeddedSource.length;
          }
          var lang = style.substring(5);
          // Decorate the left of the embedded source
          appendDecorations(basePos + tokenStart, token.substring(0,
              embeddedSourceStart), decorate, decorations);
          // Decorate the embedded source
          appendDecorations(basePos + tokenStart + embeddedSourceStart,
              embeddedSource, langHandlerForExtension(lang, embeddedSource),
              decorations);
          // Decorate the right of the embedded section
          appendDecorations(basePos + tokenStart + embeddedSourceEnd, token
              .substring(embeddedSourceEnd), decorate, decorations);
        }
      }
      job.decorations = decorations;
    };
    return decorate;
  }

  /**
   * returns a function that produces a list of decorations from source text.
   * 
   * This code treats ", ', and ` as string delimiters, and \ as a string
   * escape. It does not recognize perl's qq() style strings. It has no special
   * handling for double delimiter escapes as in basic, or the tripled
   * delimiters used in python, but should work on those regardless although in
   * those cases a single string literal may be broken up into multiple adjacent
   * string literals.
   * 
   * It recognizes C, C++, and shell style comments.
   * 
   * @param {Object}
   *          options a set of optional parameters.
   * @return {function (Object)} a function that examines the source code in the
   *         input job and builds the decoration list.
   */
  function sourceDecorator(options) {
    var shortcutStylePatterns = [], fallthroughStylePatterns = [];
    if (options['tripleQuotedStrings']) {
      // '''multi-line-string''', 'single-line-string', and double-quoted
      shortcutStylePatterns
          .push([
              PR_STRING,
              /^(?:\'\'\'(?:[^\'\\]|\\[\s\S]|\'{1,2}(?=[^\']))*(?:\'\'\'|$)|\"\"\"(?:[^\"\\]|\\[\s\S]|\"{1,2}(?=[^\"]))*(?:\"\"\"|$)|\'(?:[^\\\']|\\[\s\S])*(?:\'|$)|\"(?:[^\\\"]|\\[\s\S])*(?:\"|$))/,
              null, '\'"' ]);
    } else if (options['multiLineStrings']) {
      // 'multi-line-string', "multi-line-string"
      shortcutStylePatterns
          .push([
              PR_STRING,
              /^(?:\'(?:[^\\\']|\\[\s\S])*(?:\'|$)|\"(?:[^\\\"]|\\[\s\S])*(?:\"|$)|\`(?:[^\\\`]|\\[\s\S])*(?:\`|$))/,
              null, '\'"`' ]);
    } else {
      // 'single-line-string', "single-line-string"
      shortcutStylePatterns.push([ PR_STRING,
          /^(?:\'(?:[^\\\'\r\n]|\\.)*(?:\'|$)|\"(?:[^\\\"\r\n]|\\.)*(?:\"|$))/,
          null, '"\'' ]);
    }
    if (options['verbatimStrings']) {
      // verbatim-string-literal production from the C# grammar. See issue 93.
      fallthroughStylePatterns.push([ PR_STRING, /^@\"(?:[^\"]|\"\")*(?:\"|$)/,
          null ]);
    }
    if (options['hashComments']) {
      if (options['cStyleComments']) {
        // Stop C preprocessor declarations at an unclosed open comment
        shortcutStylePatterns
            .push([
                PR_COMMENT,
                /^#(?:(?:define|elif|else|endif|error|ifdef|include|ifndef|line|pragma|undef|warning)\b|[^\r\n]*)/,
                null, '#' ]);
        fallthroughStylePatterns
            .push([
                PR_STRING,
                /^<(?:(?:(?:\.\.\/)*|\/?)(?:[\w-]+(?:\/[\w-]+)+)?[\w-]+\.h|[a-z]\w*)>/,
                null ]);
      } else {
        shortcutStylePatterns.push([ PR_COMMENT, /^#[^\r\n]*/, null, '#' ]);
      }
    }
    if (options['cStyleComments']) {
      fallthroughStylePatterns.push([ PR_COMMENT, /^\/\/[^\r\n]*/, null ]);
      fallthroughStylePatterns.push([ PR_COMMENT, /^\/\*[\s\S]*?(?:\*\/|$)/,
          null ]);
    }
    if (options['regexLiterals']) {
      var REGEX_LITERAL = (
      // A regular expression literal starts with a slash that is
      // not followed by * or / so that it is not confused with
      // comments.
      '/(?=[^/*])'
      // and then contains any number of raw characters,
      + '(?:[^/\\x5B\\x5C]'
      // escape sequences (\x5C),
      + '|\\x5C[\\s\\S]'
      // or non-nesting character sets (\x5B\x5D);
      + '|\\x5B(?:[^\\x5C\\x5D]|\\x5C[\\s\\S])*(?:\\x5D|$))+'
      // finally closed by a /.
      + '/');
      fallthroughStylePatterns
          .push([
              'lang-regex',
              new RegExp('^' + REGEXP_PRECEDER_PATTERN + '(' + REGEX_LITERAL
                  + ')') ]);
    }

    var keywords = options['keywords'].replace(/^\s+|\s+$/g, '');
    if (keywords.length) {
      fallthroughStylePatterns.push([ PR_KEYWORD,
          new RegExp('^(?:' + keywords.replace(/\s+/g, '|') + ')\\b'), null ]);
    }

    shortcutStylePatterns.push([ PR_PLAIN, /^\s+/, null, ' \r\n\t\xA0' ]);
    fallthroughStylePatterns.push(
    // TODO(mikesamuel): recognize non-latin letters and numerals in idents
    [ PR_LITERAL, /^@[a-z_$][a-z_$@0-9]*/i, null ], [ PR_TYPE,
        /^@?[A-Z]+[a-z][A-Za-z_$@0-9]*/, null ], [ PR_PLAIN,
        /^[a-z_$][a-z_$@0-9]*/i, null ], [ PR_LITERAL, new RegExp('^(?:'
    // A hex number
    + '0x[a-f0-9]+'
    // or an octal or decimal number,
    + '|(?:\\d(?:_\\d+)*\\d*(?:\\.\\d*)?|\\.\\d\\+)'
    // possibly in scientific notation
    + '(?:e[+\\-]?\\d+)?' + ')'
    // with an optional modifier like UL for unsigned long
    + '[a-z]*', 'i'), null, '0123456789' ], [ PR_PUNCTUATION,
        /^.[^\s\w\.$@\'\"\`\/\#]*/, null ]);

    return createSimpleLexer(shortcutStylePatterns, fallthroughStylePatterns);
  }

  var decorateSource = sourceDecorator({
    'keywords' : ALL_KEYWORDS,
    'hashComments' : true,
    'cStyleComments' : true,
    'multiLineStrings' : true,
    'regexLiterals' : true
  });

  /**
   * Breaks {@code job.source} around style boundaries in
   * {@code job.decorations} while re-interleaving {@code job.extractedTags},
   * and leaves the result in {@code job.prettyPrintedHtml}.
   * 
   * @param {Object}
   *          job like { source: {string} source as plain text, extractedTags:
   *          {Array.<number|string>} extractedTags chunks of raw html preceded
   *          by their position in {@code job.source} in order decorations:
   *          {Array.<number|string} an array of style classes preceded by the
   *          position at which they start in job.source in order }
   * @private
   */
  function recombineTagsAndDecorations(job) {
    var sourceText = job.source;
    var extractedTags = job.extractedTags;
    var decorations = job.decorations;

    var html = [];
    // index past the last char in sourceText written to html
    var outputIdx = 0;

    var openDecoration = null;
    var currentDecoration = null;
    var tagPos = 0; // index into extractedTags
    var decPos = 0; // index into decorations
    var tabExpander = makeTabExpander(window['PR_TAB_WIDTH']);

    var adjacentSpaceRe = /([\r\n ]) /g;
    var startOrSpaceRe = /(^| ) /gm;
    var newlineRe = /\r\n?|\n/g;
    var trailingSpaceRe = /[ \r\n]$/;
    var lastWasSpace = true; // the last text chunk emitted ended with a space.

    // A helper function that is responsible for opening sections of decoration
    // and outputing properly escaped chunks of source
    function emitTextUpTo(sourceIdx) {
      if (sourceIdx > outputIdx) {
        if (openDecoration && openDecoration !== currentDecoration) {
          // Close the current decoration
          html.push('</span>');
          openDecoration = null;
        }
        if (!openDecoration && currentDecoration) {
          openDecoration = currentDecoration;
          html.push('<span class="', openDecoration, '">');
        }
        // This interacts badly with some wikis which introduces paragraph tags
        // into pre blocks for some strange reason.
        // It's necessary for IE though which seems to lose the preformattedness
        // of <pre> tags when their innerHTML is assigned.
        // http://stud3.tuwien.ac.at/~e0226430/innerHtmlQuirk.html
        // and it serves to undo the conversion of <br>s to newlines done in
        // chunkify.
        var htmlChunk = textToHtml(
            tabExpander(sourceText.substring(outputIdx, sourceIdx))).replace(
            lastWasSpace ? startOrSpaceRe : adjacentSpaceRe, '$1&nbsp;');
        // Keep track of whether we need to escape space at the beginning of the
        // next chunk.
        lastWasSpace = trailingSpaceRe.test(htmlChunk);
        // IE collapses multiple adjacient <br>s into 1 line break.
        // Prefix every <br> with '&nbsp;' can prevent such IE's behavior.
        var lineBreakHtml = window['_pr_isIE6']() ? '&nbsp;<br />' : '<br />';
        html.push(htmlChunk.replace(newlineRe, lineBreakHtml));
        outputIdx = sourceIdx;
      }
    }

    while (true) {
      // Determine if we're going to consume a tag this time around. Otherwise
      // we consume a decoration or exit.
      var outputTag;
      if (tagPos < extractedTags.length) {
        if (decPos < decorations.length) {
          // Pick one giving preference to extractedTags since we shouldn't open
          // a new style that we're going to have to immediately close in order
          // to output a tag.
          outputTag = extractedTags[tagPos] <= decorations[decPos];
        } else {
          outputTag = true;
        }
      } else {
        outputTag = false;
      }
      // Consume either a decoration or a tag or exit.
      if (outputTag) {
        emitTextUpTo(extractedTags[tagPos]);
        if (openDecoration) {
          // Close the current decoration
          html.push('</span>');
          openDecoration = null;
        }
        html.push(extractedTags[tagPos + 1]);
        tagPos += 2;
      } else if (decPos < decorations.length) {
        emitTextUpTo(decorations[decPos]);
        currentDecoration = decorations[decPos + 1];
        decPos += 2;
      } else {
        break;
      }
    }
    emitTextUpTo(sourceText.length);
    if (openDecoration) {
      html.push('</span>');
    }
    job.prettyPrintedHtml = html.join('');
  }

  /** Maps language-specific file extensions to handlers. */
  var langHandlerRegistry = {};
  /**
   * Register a language handler for the given file extensions.
   * 
   * @param {function
   *          (Object)} handler a function from source code to a list of
   *          decorations. Takes a single argument job which describes the state
   *          of the computation. The single parameter has the form {@code {
   *          source: {string} as plain text. decorations: {Array.<number|string>}
   *          an array of style classes preceded by the position at which they
   *          start in job.source in order. The language handler should assigned
   *          this field. basePos: {int} the position of source in the larger
   *          source chunk. All positions in the output decorations array are
   *          relative to the larger source chunk. } }
   * @param {Array.
   *          <string>} fileExtensions
   */
  function registerLangHandler(handler, fileExtensions) {
    for ( var i = fileExtensions.length; --i >= 0;) {
      var ext = fileExtensions[i];
      if (!langHandlerRegistry.hasOwnProperty(ext)) {
        langHandlerRegistry[ext] = handler;
      } else if ('console' in window) {
        console.warn('cannot override language handler %s', ext);
      }
    }
  }
  function langHandlerForExtension(extension, source) {
    if (!(extension && langHandlerRegistry.hasOwnProperty(extension))) {
      // Treat it as markup if the first non whitespace character is a < and
      // the last non-whitespace character is a >.
      extension = /^\s*</.test(source) ? 'default-markup' : 'default-code';
    }
    return langHandlerRegistry[extension];
  }
  registerLangHandler(decorateSource, [ 'default-code' ]);
  registerLangHandler(createSimpleLexer([], [ [ PR_PLAIN, /^[^<?]+/ ],
      [ PR_DECLARATION, /^<!\w[^>]*(?:>|$)/ ],
      [ PR_COMMENT, /^<\!--[\s\S]*?(?:-\->|$)/ ],
      // Unescaped content in an unknown language
      [ 'lang-', /^<\?([\s\S]+?)(?:\?>|$)/ ],
      [ 'lang-', /^<%([\s\S]+?)(?:%>|$)/ ],
      [ PR_PUNCTUATION, /^(?:<[%?]|[%?]>)/ ],
      [ 'lang-', /^<xmp\b[^>]*>([\s\S]+?)<\/xmp\b[^>]*>/i ],
      // Unescaped content in javascript. (Or possibly vbscript).
      [ 'lang-js', /^<script\b[^>]*>([\s\S]*?)(<\/script\b[^>]*>)/i ],
      // Contains unescaped stylesheet content
      [ 'lang-css', /^<style\b[^>]*>([\s\S]*?)(<\/style\b[^>]*>)/i ],
      [ 'lang-in.tag', /^(<\/?[a-z][^<>]*>)/i ] ]), [ 'default-markup', 'htm',
      'html', 'mxml', 'xhtml', 'xml', 'xsl' ]);
  registerLangHandler(createSimpleLexer([
      [ PR_PLAIN, /^[\s]+/, null, ' \t\r\n' ],
      [ PR_ATTRIB_VALUE, /^(?:\"[^\"]*\"?|\'[^\']*\'?)/, null, '\"\'' ] ], [
      [ PR_TAG, /^^<\/?[a-z](?:[\w.:-]*\w)?|\/?>$/i ],
      [ PR_ATTRIB_NAME, /^(?!style[\s=]|on)[a-z](?:[\w:-]*\w)?/i ],
      [ 'lang-uq.val', /^=\s*([^>\'\"\s]*(?:[^>\'\"\s\/]|\/(?=\s)))/ ],
      [ PR_PUNCTUATION, /^[=<>\/]+/ ],
      [ 'lang-js', /^on\w+\s*=\s*\"([^\"]+)\"/i ],
      [ 'lang-js', /^on\w+\s*=\s*\'([^\']+)\'/i ],
      [ 'lang-js', /^on\w+\s*=\s*([^\"\'>\s]+)/i ],
      [ 'lang-css', /^style\s*=\s*\"([^\"]+)\"/i ],
      [ 'lang-css', /^style\s*=\s*\'([^\']+)\'/i ],
      [ 'lang-css', /^style\s*=\s*([^\"\'>\s]+)/i ] ]), [ 'in.tag' ]);
  registerLangHandler(
      createSimpleLexer([], [ [ PR_ATTRIB_VALUE, /^[\s\S]+/ ] ]), [ 'uq.val' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : CPP_KEYWORDS,
    'hashComments' : true,
    'cStyleComments' : true
  }), [ 'c', 'cc', 'cpp', 'cxx', 'cyc', 'm' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : 'null true false'
  }), [ 'json' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : CSHARP_KEYWORDS,
    'hashComments' : true,
    'cStyleComments' : true,
    'verbatimStrings' : true
  }), [ 'cs' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : JAVA_KEYWORDS,
    'cStyleComments' : true
  }), [ 'java' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : SH_KEYWORDS,
    'hashComments' : true,
    'multiLineStrings' : true
  }), [ 'bsh', 'csh', 'sh' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : PYTHON_KEYWORDS,
    'hashComments' : true,
    'multiLineStrings' : true,
    'tripleQuotedStrings' : true
  }), [ 'cv', 'py' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : PERL_KEYWORDS,
    'hashComments' : true,
    'multiLineStrings' : true,
    'regexLiterals' : true
  }), [ 'perl', 'pl', 'pm' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : RUBY_KEYWORDS,
    'hashComments' : true,
    'multiLineStrings' : true,
    'regexLiterals' : true
  }), [ 'rb' ]);
  registerLangHandler(sourceDecorator({
    'keywords' : JSCRIPT_KEYWORDS,
    'cStyleComments' : true,
    'regexLiterals' : true
  }), [ 'js' ]);
  registerLangHandler(createSimpleLexer([], [ [ PR_STRING, /^[\s\S]+/ ] ]),
      [ 'regex' ]);

  function applyDecorator(job) {
    var sourceCodeHtml = job.sourceCodeHtml;
    var opt_langExtension = job.langExtension;

    // Prepopulate output in case processing fails with an exception.
    job.prettyPrintedHtml = sourceCodeHtml;

    try {
      // Extract tags, and convert the source code to plain text.
      var sourceAndExtractedTags = extractTags(sourceCodeHtml);
      /**
       * Plain text.
       * 
       * @type {string}
       */
      var source = sourceAndExtractedTags.source;
      job.source = source;
      job.basePos = 0;

      /**
       * Even entries are positions in source in ascending order. Odd entries
       * are tags that were extracted at that position.
       * 
       * @type {Array.<number|string>}
       */
      job.extractedTags = sourceAndExtractedTags.tags;

      // Apply the appropriate language handler
      langHandlerForExtension(opt_langExtension, source)(job);
      // Integrate the decorations and tags back into the source code to produce
      // a decorated html string which is left in job.prettyPrintedHtml.
      recombineTagsAndDecorations(job);
    } catch (e) {
      if ('console' in window) {
        console.log(e);
        console.trace();
      }
    }
  }

  function prettyPrintOne(sourceCodeHtml, opt_langExtension) {
    var job = {
      sourceCodeHtml : sourceCodeHtml,
      langExtension : opt_langExtension
    };
    applyDecorator(job);
    return job.prettyPrintedHtml;
  }

  function prettyPrint(opt_whenDone) {
    var isIE678 = window['_pr_isIE6']();
    var ieNewline = isIE678 === 6 ? '\r\n' : '\r';
    // See bug 71 and http://stackoverflow.com/questions/136443/why-doesnt-ie7-

    // fetch a list of nodes to rewrite
    var codeSegments = [ document.getElementsByTagName('pre'),
        document.getElementsByTagName('code'),
        document.getElementsByTagName('xmp') ];
    var elements = [];
    for ( var i = 0; i < codeSegments.length; ++i) {
      for ( var j = 0, n = codeSegments[i].length; j < n; ++j) {
        elements.push(codeSegments[i][j]);
      }
    }
    codeSegments = null;

    var clock = Date;
    if (!clock['now']) {
      clock = {
        'now' : function() {
          return (new Date).getTime();
        }
      };
    }

    // The loop is broken into a series of continuations to make sure that we
    // don't make the browser unresponsive when rewriting a large page.
    var k = 0;
    var prettyPrintingJob;

    function doWork() {
      var endTime = (window['PR_SHOULD_USE_CONTINUATION'] ? clock.now() + 250 /* ms */
          : Infinity);
      for (; k < elements.length && clock.now() < endTime; k++) {
        var cs = elements[k];
        if (cs.className && cs.className.indexOf('prettyprint') >= 0) {
          // If the classes includes a language extensions, use it.
          // Language extensions can be specified like
          // <pre class="prettyprint lang-cpp">
          // the language extension "cpp" is used to find a language handler as
          // passed to PR_registerLangHandler.
          var langExtension = cs.className.match(/\blang-(\w+)\b/);
          if (langExtension) {
            langExtension = langExtension[1];
          }

          // make sure this is not nested in an already prettified element
          var nested = false;
          for ( var p = cs.parentNode; p; p = p.parentNode) {
            if ((p.tagName === 'pre' || p.tagName === 'code' || p.tagName === 'xmp')
                && p.className && p.className.indexOf('prettyprint') >= 0) {
              nested = true;
              break;
            }
          }
          if (!nested) {
            // fetch the content as a snippet of properly escaped HTML.
            // Firefox adds newlines at the end.
            var content = getInnerHtml(cs);
            content = content.replace(/(?:\r\n?|\n)$/, '');

            // do the pretty printing
            prettyPrintingJob = {
              sourceCodeHtml : content,
              langExtension : langExtension,
              sourceNode : cs
            };
            applyDecorator(prettyPrintingJob);
            replaceWithPrettyPrintedHtml();
          }
        }
      }
      if (k < elements.length) {
        // finish up in a continuation
        setTimeout(doWork, 250);
      } else if (opt_whenDone) {
        opt_whenDone();
      }
    }

    function replaceWithPrettyPrintedHtml() {
      var newContent = prettyPrintingJob.prettyPrintedHtml;
      if (!newContent) {
        return;
      }
      var cs = prettyPrintingJob.sourceNode;

      // push the prettified html back into the tag.
      if (!isRawContent(cs)) {
        // just replace the old html with the new
        cs.innerHTML = newContent;
      } else {
        // we need to change the tag to a <pre> since <xmp>s do not allow
        // embedded tags such as the span tags used to attach styles to
        // sections of source code.
        var pre = document.createElement('PRE');
        for ( var i = 0; i < cs.attributes.length; ++i) {
          var a = cs.attributes[i];
          if (a.specified) {
            var aname = a.name.toLowerCase();
            if (aname === 'class') {
              pre.className = a.value; // For IE 6
            } else {
              pre.setAttribute(a.name, a.value);
            }
          }
        }
        pre.innerHTML = newContent;

        // remove the old
        cs.parentNode.replaceChild(pre, cs);
        cs = pre;
      }

      // Replace <br>s with line-feeds so that copying and pasting works
      // on IE 6.
      // Doing this on other browsers breaks lots of stuff since \r\n is
      // treated as two newlines on Firefox, and doing this also slows
      // down rendering.
      if (isIE678 && cs.tagName === 'PRE') {
        var lineBreaks = cs.getElementsByTagName('br');
        for ( var j = lineBreaks.length; --j >= 0;) {
          var lineBreak = lineBreaks[j];
          lineBreak.parentNode.replaceChild(document.createTextNode(ieNewline),
              lineBreak);
        }
      }
    }

    doWork();
  }

  window['PR_normalizedHtml'] = normalizedHtml;
  window['prettyPrintOne'] = prettyPrintOne;
  window['prettyPrint'] = prettyPrint;
  window['PR'] = {
    'combinePrefixPatterns' : combinePrefixPatterns,
    'createSimpleLexer' : createSimpleLexer,
    'registerLangHandler' : registerLangHandler,
    'sourceDecorator' : sourceDecorator,
    'PR_ATTRIB_NAME' : PR_ATTRIB_NAME,
    'PR_ATTRIB_VALUE' : PR_ATTRIB_VALUE,
    'PR_COMMENT' : PR_COMMENT,
    'PR_DECLARATION' : PR_DECLARATION,
    'PR_KEYWORD' : PR_KEYWORD,
    'PR_LITERAL' : PR_LITERAL,
    'PR_NOCODE' : PR_NOCODE,
    'PR_PLAIN' : PR_PLAIN,
    'PR_PUNCTUATION' : PR_PUNCTUATION,
    'PR_SOURCE' : PR_SOURCE,
    'PR_STRING' : PR_STRING,
    'PR_TAG' : PR_TAG,
    'PR_TYPE' : PR_TYPE
  };
})();
