view lib/assets/javascripts/prettify.js @ 83:ae360c3b0bb0

Disable explain when using jruby because it's not supported. The patch for this support exist but for some reason still not included in latest release of the jdbc adapter. Reference: https://github.com/jruby/activerecord-jdbc-adapter/pull/206
author Edho Arief <edho@myconan.net>
date Mon, 15 Oct 2012 03:45:18 -0700
parents 33b47c2160a3
children
line wrap: on
line source

// Copyright (C) 2006 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.


/**
 * @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
 */

// 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;

(function () {
  // Keyword lists for various languages.
  // We use things that coerce to strings to make them compact when minified
  // and to defeat aggressive optimizers that fold large string constants.
  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,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,dynamic,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 COFFEE_KEYWORDS = "all,and,by,catch,class,else,extends,false,finally," +
      "for,if,in,is,isnt,loop,new,no,not,null,of,off,on,or,return,super,then," +
      "true,try,unless,until,when,while,yes";
  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];
  var C_TYPES = /^(DIR|FILE|vector|(de|priority_)?queue|list|stack|(const_)?iterator|(multi)?(set|map)|bitset|u?(int|float)\d*)/;

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

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



/**
 * A set of tokens that can precede a regular expression literal in
 * javascript
 * http://web.archive.org/web/20070717142515/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
 * @const
 */
var REGEXP_PRECEDER_PATTERN = '(?:^^\\.?|[+-]|\\!|\\!=|\\!==|\\#|\\%|\\%=|&|&&|&&=|&=|\\(|\\*|\\*=|\\+=|\\,|\\-=|\\->|\\/|\\/=|:|::|\\;|<|<<|<<=|<=|=|==|===|>|>=|>>|>>=|>>>|>>>=|\\?|\\@|\\[|\\^|\\^=|\\^\\^|\\^\\^=|\\{|\\||\\|=|\\|\\||\\|\\|=|\\~|break|case|continue|delete|do|else|finally|instanceof|return|throw|try|typeof)\\s*';

// 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.


  /**
   * Given a group of {@link RegExp}s, returns a {@code RegExp} that globally
   * matches the union of the sets of strings matched 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;
      }
    }
  
    var escapeCharToCodeUnit = {
      'b': 8,
      't': 9,
      'n': 0xa,
      'v': 0xb,
      'f': 0xc,
      'r': 0xd
    };
  
    function decodeEscape(charsetPart) {
      var cc0 = charsetPart.charCodeAt(0);
      if (cc0 !== 92 /* \\ */) {
        return cc0;
      }
      var c1 = charsetPart.charAt(1);
      cc0 = escapeCharToCodeUnit[c1];
      if (cc0) {
        return cc0;
      } else if ('0' <= c1 && c1 <= '7') {
        return parseInt(charsetPart.substring(1), 8);
      } else if (c1 === 'u' || c1 === 'x') {
        return parseInt(charsetPart.substring(2), 16);
      } else {
        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];
        if (/\\[bdsw]/i.test(p)) {  // Don't muck with named groups.
          groups.push(p);
        } else {
          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.
          // This case handling is too simplistic.
          // It does not deal with non-latin case folding.
          // It works for latin source code identifiers though.
          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 groups 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');
  }


  /**
   * Split markup into a string of source code and an array mapping ranges in
   * that string to the text nodes in which they appear.
   *
   * <p>
   * The HTML DOM structure:</p>
   * <pre>
   * (Element   "p"
   *   (Element "b"
   *     (Text  "print "))       ; #1
   *   (Text    "'Hello '")      ; #2
   *   (Element "br")            ; #3
   *   (Text    "  + 'World';")) ; #4
   * </pre>
   * <p>
   * corresponds to the HTML
   * {@code <p><b>print </b>'Hello '<br>  + 'World';</p>}.</p>
   *
   * <p>
   * It will produce the output:</p>
   * <pre>
   * {
   *   sourceCode: "print 'Hello '\n  + 'World';",
   *   //                 1         2
   *   //       012345678901234 5678901234567
   *   spans: [0, #1, 6, #2, 14, #3, 15, #4]
   * }
   * </pre>
   * <p>
   * where #1 is a reference to the {@code "print "} text node above, and so
   * on for the other text nodes.
   * </p>
   *
   * <p>
   * The {@code} spans array is an array of pairs.  Even elements are the start
   * indices of substrings, and odd elements are the text nodes (or BR elements)
   * that contain the text for those substrings.
   * Substrings continue until the next index or the end of the source.
   * </p>
   *
   * @param {Node} node an HTML DOM subtree containing source-code.
   * @return {Object} source code and the text nodes in which they occur.
   */
  function extractSourceSpans(node) {
    var nocode = /(?:^|\s)nocode(?:\s|$)/;
  
    var chunks = [];
    var length = 0;
    var spans = [];
    var k = 0;
  
    var whitespace;
    if (node.currentStyle) {
      whitespace = node.currentStyle.whiteSpace;
    } else if (window.getComputedStyle) {
      whitespace = document.defaultView.getComputedStyle(node, null)
          .getPropertyValue('white-space');
    }
    var isPreformatted = whitespace && 'pre' === whitespace.substring(0, 3);
  
    function walk(node) {
      switch (node.nodeType) {
        case 1:  // Element
          if (nocode.test(node.className)) { return; }
          for (var child = node.firstChild; child; child = child.nextSibling) {
            walk(child);
          }
          var nodeName = node.nodeName;
          if ('BR' === nodeName || 'LI' === nodeName) {
            chunks[k] = '\n';
            spans[k << 1] = length++;
            spans[(k++ << 1) | 1] = node;
          }
          break;
        case 3: case 4:  // Text
          var text = node.nodeValue;
          if (text.length) {
            if (!isPreformatted) {
              text = text.replace(/[ \t\r\n]+/g, ' ');
            } else {
              text = text.replace(/\r\n?/g, '\n');  // Normalize newlines.
            }
            // TODO: handle tabs here?
            chunks[k] = text;
            spans[k << 1] = length;
            length += text.length;
            spans[(k++ << 1) | 1] = node;
          }
          break;
      }
    }
  
    walk(node);
  
    return {
      sourceCode: chunks.join('').replace(/\n$/, ''),
      spans: spans
    };
  }


  /**
   * 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 = {
      sourceCode: sourceCode,
      basePos: basePos
    };
    langHandler(job);
    out.push.apply(out, job.decorations);
  }

  var notWs = /\S/;

  /**
   * Given an element, if it contains only one child element and any text nodes
   * it contains contain only space characters, return the sole child element.
   * Otherwise returns undefined.
   * <p>
   * This is meant to return the CODE element in {@code <pre><code ...>} when
   * there is a single child element that contains all the non-space textual
   * content, but not to return anything where there are multiple child elements
   * as in {@code <pre><code>...</code><code>...</code></pre>} or when there
   * is textual content.
   */
  function childContentWrapper(element) {
    var wrapper = undefined;
    for (var c = element.firstChild; c; c = c.nextSibling) {
      var type = c.nodeType;
      wrapper = (type === 1)  // Element Node
          ? (wrapper ? element : c)
          : (type === 3)  // Text Node
          ? (notWs.test(c.nodeValue) ? element : wrapper)
          : wrapper;
    }
    return wrapper === element ? undefined : wrapper;
  }

  /** 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;

    /**
     * Lexes job.sourceCode and produces an output array job.decorations of
     * style classes preceded by the position at which they start in
     * job.sourceCode in order.
     *
     * @param {Object} job an object like <pre>{
     *    sourceCode: {string} sourceText plain text,
     *    basePos: {int} position of job.sourceCode in the larger chunk of
     *        sourceCode.
     * }</pre>
     */
    var decorate = function (job) {
      var sourceCode = job.sourceCode, 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]);
    }
    var hc = options['hashComments'];
    if (hc) {
      if (options['cStyleComments']) {
        if (hc > 1) {  // multiline hash comments
          shortcutStylePatterns.push(
              [PR_COMMENT, /^#(?:##(?:[^#]|#(?!##))*(?:###|$)|.*)/, null, '#']);
        } else {
          // Stop C preprocessor declarations at an unclosed open comment
          shortcutStylePatterns.push(
              [PR_COMMENT, /^#(?:(?:define|elif|else|endif|error|ifdef|include|ifndef|line|pragma|undef|warning)\b|[^\r\n]*)/,
               null, '#']);
        }
        fallthroughStylePatterns.push(
            [PR_STRING,
             /^<(?:(?:(?:\.\.\/)*|\/?)(?:[\w-]+(?:\/[\w-]+)+)?[\w-]+\.h|[a-z]\w*)>/,
             null]);
      } else {
        shortcutStylePatterns.push([PR_COMMENT, /^#[^\r\n]*/, null, '#']);
      }
    }
    if (options['cStyleComments']) {
      fallthroughStylePatterns.push([PR_COMMENT, /^\/\/[^\r\n]*/, null]);
      fallthroughStylePatterns.push(
          [PR_COMMENT, /^\/\*[\s\S]*?(?:\*\/|$)/, null]);
    }
    if (options['regexLiterals']) {
      /**
       * @const
       */
      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 types = options['types'];
    if (types) {
      fallthroughStylePatterns.push([PR_TYPE, types]);
    }

    var keywords = ("" + options['keywords']).replace(/^ | $/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_$@0-9]*|\w+_t\b)/, null],
        [PR_PLAIN,       /^[a-z_$][a-z_$@0-9]*/i, null],
        [PR_LITERAL,
         new RegExp(
             '^(?:'
             // A hex number
             + '0x[a-f0-9]+'
             // or an octal or decimal number,
             + '|(?:\\d(?:_\\d+)*\\d*(?:\\.\\d*)?|\\.\\d\\+)'
             // possibly in scientific notation
             + '(?:e[+\\-]?\\d+)?'
             + ')'
             // with an optional modifier like UL for unsigned long
             + '[a-z]*', 'i'),
         null, '0123456789'],
        // Don't treat escaped quotes in bash as starting strings.  See issue 144.
        [PR_PLAIN,       /^\\[\s\S]?/, null],
        [PR_PUNCTUATION, /^.[^\s\w\.$@\'\"\`\/\#\\]*/, null]);

    return createSimpleLexer(shortcutStylePatterns, fallthroughStylePatterns);
  }

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

  /**
   * Given a DOM subtree, wraps it in a list, and puts each line into its own
   * list item.
   *
   * @param {Node} node modified in place.  Its content is pulled into an
   *     HTMLOListElement, and each line is moved into a separate list item.
   *     This requires cloning elements, so the input might not have unique
   *     IDs after numbering.
   */
  function numberLines(node, opt_startLineNum) {
    var nocode = /(?:^|\s)nocode(?:\s|$)/;
    var lineBreak = /\r\n?|\n/;
  
    var document = node.ownerDocument;
  
    var whitespace;
    if (node.currentStyle) {
      whitespace = node.currentStyle.whiteSpace;
    } else if (window.getComputedStyle) {
      whitespace = document.defaultView.getComputedStyle(node, null)
          .getPropertyValue('white-space');
    }
    // If it's preformatted, then we need to split lines on line breaks
    // in addition to <BR>s.
    var isPreformatted = whitespace && 'pre' === whitespace.substring(0, 3);
  
    var li = document.createElement('LI');
    while (node.firstChild) {
      li.appendChild(node.firstChild);
    }
    // An array of lines.  We split below, so this is initialized to one
    // un-split line.
    var listItems = [li];
  
    function walk(node) {
      switch (node.nodeType) {
        case 1:  // Element
          if (nocode.test(node.className)) { break; }
          if ('BR' === node.nodeName) {
            breakAfter(node);
            // Discard the <BR> since it is now flush against a </LI>.
            if (node.parentNode) {
              node.parentNode.removeChild(node);
            }
          } else {
            for (var child = node.firstChild; child; child = child.nextSibling) {
              walk(child);
            }
          }
          break;
        case 3: case 4:  // Text
          if (isPreformatted) {
            var text = node.nodeValue;
            var match = text.match(lineBreak);
            if (match) {
              var firstLine = text.substring(0, match.index);
              node.nodeValue = firstLine;
              var tail = text.substring(match.index + match[0].length);
              if (tail) {
                var parent = node.parentNode;
                parent.insertBefore(
                    document.createTextNode(tail), node.nextSibling);
              }
              breakAfter(node);
              if (!firstLine) {
                // Don't leave blank text nodes in the DOM.
                node.parentNode.removeChild(node);
              }
            }
          }
          break;
      }
    }
  
    // Split a line after the given node.
    function breakAfter(lineEndNode) {
      // If there's nothing to the right, then we can skip ending the line
      // here, and move root-wards since splitting just before an end-tag
      // would require us to create a bunch of empty copies.
      while (!lineEndNode.nextSibling) {
        lineEndNode = lineEndNode.parentNode;
        if (!lineEndNode) { return; }
      }
  
      function breakLeftOf(limit, copy) {
        // Clone shallowly if this node needs to be on both sides of the break.
        var rightSide = copy ? limit.cloneNode(false) : limit;
        var parent = limit.parentNode;
        if (parent) {
          // We clone the parent chain.
          // This helps us resurrect important styling elements that cross lines.
          // E.g. in <i>Foo<br>Bar</i>
          // should be rewritten to <li><i>Foo</i></li><li><i>Bar</i></li>.
          var parentClone = breakLeftOf(parent, 1);
          // Move the clone and everything to the right of the original
          // onto the cloned parent.
          var next = limit.nextSibling;
          parentClone.appendChild(rightSide);
          for (var sibling = next; sibling; sibling = next) {
            next = sibling.nextSibling;
            parentClone.appendChild(sibling);
          }
        }
        return rightSide;
      }
  
      var copiedListItem = breakLeftOf(lineEndNode.nextSibling, 0);
  
      // Walk the parent chain until we reach an unattached LI.
      for (var parent;
           // Check nodeType since IE invents document fragments.
           (parent = copiedListItem.parentNode) && parent.nodeType === 1;) {
        copiedListItem = parent;
      }
      // Put it on the list of lines for later processing.
      listItems.push(copiedListItem);
    }
  
    // Split lines while there are lines left to split.
    for (var i = 0;  // Number of lines that have been split so far.
         i < listItems.length;  // length updated by breakAfter calls.
         ++i) {
      walk(listItems[i]);
    }
  
    // Make sure numeric indices show correctly.
    if (opt_startLineNum === (opt_startLineNum|0)) {
      listItems[0].setAttribute('value', opt_startLineNum);
    }
  
    var ol = document.createElement('OL');
    ol.className = 'linenums';
    var offset = Math.max(0, ((opt_startLineNum - 1 /* zero index */)) | 0) || 0;
    for (var i = 0, n = listItems.length; i < n; ++i) {
      li = listItems[i];
      // Stick a class on the LIs so that stylesheets can
      // color odd/even rows, or any other row pattern that
      // is co-prime with 10.
      li.className = 'L' + ((i + offset) % 10);
      if (!li.firstChild) {
        li.appendChild(document.createTextNode('\xA0'));
      }
      ol.appendChild(li);
    }
  
    node.appendChild(ol);
  }

  /**
   * Breaks {@code job.sourceCode} around style boundaries in
   * {@code job.decorations} and modifies {@code job.sourceNode} in place.
   * @param {Object} job like <pre>{
   *    sourceCode: {string} source as plain text,
   *    spans: {Array.<number|Node>} alternating span start indices into source
   *       and the text node or element (e.g. {@code <BR>}) corresponding to that
   *       span.
   *    decorations: {Array.<number|string} an array of style classes preceded
   *       by the position at which they start in job.sourceCode in order
   * }</pre>
   * @private
   */
  function recombineTagsAndDecorations(job) {
    var isIE = /\bMSIE\b/.test(navigator.userAgent);
    var newlineRe = /\n/g;
  
    var source = job.sourceCode;
    var sourceLength = source.length;
    // Index into source after the last code-unit recombined.
    var sourceIndex = 0;
  
    var spans = job.spans;
    var nSpans = spans.length;
    // Index into spans after the last span which ends at or before sourceIndex.
    var spanIndex = 0;
  
    var decorations = job.decorations;
    var nDecorations = decorations.length;
    // Index into decorations after the last decoration which ends at or before
    // sourceIndex.
    var decorationIndex = 0;
  
    // Remove all zero-length decorations.
    decorations[nDecorations] = sourceLength;
    var decPos, i;
    for (i = decPos = 0; i < nDecorations;) {
      if (decorations[i] !== decorations[i + 2]) {
        decorations[decPos++] = decorations[i++];
        decorations[decPos++] = decorations[i++];
      } else {
        i += 2;
      }
    }
    nDecorations = decPos;
  
    // Simplify decorations.
    for (i = decPos = 0; i < nDecorations;) {
      var startPos = decorations[i];
      // Conflate all adjacent decorations that use the same style.
      var startDec = decorations[i + 1];
      var end = i + 2;
      while (end + 2 <= nDecorations && decorations[end + 1] === startDec) {
        end += 2;
      }
      decorations[decPos++] = startPos;
      decorations[decPos++] = startDec;
      i = end;
    }
  
    nDecorations = decorations.length = decPos;
  
    var decoration = null;
    while (spanIndex < nSpans) {
      var spanStart = spans[spanIndex];
      var spanEnd = spans[spanIndex + 2] || sourceLength;
  
      var decStart = decorations[decorationIndex];
      var decEnd = decorations[decorationIndex + 2] || sourceLength;
  
      var end = Math.min(spanEnd, decEnd);
  
      var textNode = spans[spanIndex + 1];
      var styledText;
      if (textNode.nodeType !== 1  // Don't muck with <BR>s or <LI>s
          // Don't introduce spans around empty text nodes.
          && (styledText = source.substring(sourceIndex, end))) {
        // This may seem bizarre, and it is.  Emitting LF on IE causes the
        // code to display with spaces instead of line breaks.
        // Emitting Windows standard issue linebreaks (CRLF) causes a blank
        // space to appear at the beginning of every line but the first.
        // Emitting an old Mac OS 9 line separator makes everything spiffy.
        if (isIE) { styledText = styledText.replace(newlineRe, '\r'); }
        textNode.nodeValue = styledText;
        var document = textNode.ownerDocument;
        var span = document.createElement('SPAN');
        span.className = decorations[decorationIndex + 1];
        var parentNode = textNode.parentNode;
        parentNode.replaceChild(span, textNode);
        span.appendChild(textNode);
        if (sourceIndex < spanEnd) {  // Split off a text node.
          spans[spanIndex + 1] = textNode
              // TODO: Possibly optimize by using '' if there's no flicker.
              = document.createTextNode(source.substring(end, spanEnd));
          parentNode.insertBefore(textNode, span.nextSibling);
        }
      }
  
      sourceIndex = end;
  
      if (sourceIndex >= spanEnd) {
        spanIndex += 2;
      }
      if (sourceIndex >= decEnd) {
        decorationIndex += 2;
      }
    }
  }


  /** 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 {
    *        sourceCode: {string} as plain text.
    *        decorations: {Array.<number|string>} an array of style classes
    *                     preceded by the position at which they start in
    *                     job.sourceCode 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 (window['console']) {
        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,
          'types': C_TYPES
        }), ['c', 'cc', 'cpp', 'cxx', 'cyc', 'm']);
  registerLangHandler(sourceDecorator({
          'keywords': 'null,true,false'
        }), ['json']);
  registerLangHandler(sourceDecorator({
          'keywords': CSHARP_KEYWORDS,
          'hashComments': true,
          'cStyleComments': true,
          'verbatimStrings': true,
          'types': C_TYPES
        }), ['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(sourceDecorator({
          'keywords': COFFEE_KEYWORDS,
          'hashComments': 3,  // ### style block comments
          'cStyleComments': true,
          'multilineStrings': true,
          'tripleQuotedStrings': true,
          'regexLiterals': true
        }), ['coffee']);
  registerLangHandler(createSimpleLexer([], [[PR_STRING, /^[\s\S]+/]]), ['regex']);

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

    try {
      // Extract tags, and convert the source code to plain text.
      var sourceAndSpans = extractSourceSpans(job.sourceNode);
      /** Plain text. @type {string} */
      var source = sourceAndSpans.sourceCode;
      job.sourceCode = source;
      job.spans = sourceAndSpans.spans;
      job.basePos = 0;

      // Apply the appropriate language handler
      langHandlerForExtension(opt_langExtension, source)(job);

      // Integrate the decorations and tags back into the source code,
      // modifying the sourceNode in place.
      recombineTagsAndDecorations(job);
    } catch (e) {
      if ('console' in window) {
        console['log'](e && e['stack'] ? e['stack'] : e);
      }
    }
  }

  /**
   * @param sourceCodeHtml {string} The HTML to pretty print.
   * @param opt_langExtension {string} The language name to use.
   *     Typically, a filename extension like 'cpp' or 'java'.
   * @param opt_numberLines {number|boolean} True to number lines,
   *     or the 1-indexed number of the first line in sourceCodeHtml.
   */
  function prettyPrintOne(sourceCodeHtml, opt_langExtension, opt_numberLines) {
    var container = document.createElement('PRE');
    // This could cause images to load and onload listeners to fire.
    // E.g. <img onerror="alert(1337)" src="nosuchimage.png">.
    // We assume that the inner HTML is from a trusted source.
    container.innerHTML = sourceCodeHtml;
    if (opt_numberLines) {
      numberLines(container, opt_numberLines);
    }

    var job = {
      langExtension: opt_langExtension,
      numberLines: opt_numberLines,
      sourceNode: container
    };
    applyDecorator(job);
    return container.innerHTML;
  }

  function prettyPrint(opt_whenDone) {
    function byTagName(tn) { return document.getElementsByTagName(tn); }
    // fetch a list of nodes to rewrite
    var codeSegments = [byTagName('pre'), byTagName('code'), byTagName('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); } };
    }

    // 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;

    var langExtensionRe = /\blang(?:uage)?-([\w.]+)(?!\S)/;
    var prettyPrintRe = /\bprettyprint\b/;

    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];
        var className = cs.className;
        if (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.
          // HTML5 recommends that a language be specified using "language-"
          // as the prefix instead.  Google Code Prettify supports both.
          // http://dev.w3.org/html5/spec-author-view/the-code-element.html
          var langExtension = className.match(langExtensionRe);
          // Support <pre class="prettyprint"><code class="language-c">
          var wrapper;
          if (!langExtension && (wrapper = childContentWrapper(cs))
              && "CODE" === wrapper.tagName) {
            langExtension = wrapper.className.match(langExtensionRe);
          }

          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) {
            // Look for a class like linenums or linenums:<n> where <n> is the
            // 1-indexed number of the first line.
            var lineNums = cs.className.match(/\blinenums\b(?::(\d+))?/);
            lineNums = lineNums
                  ? lineNums[1] && lineNums[1].length ? +lineNums[1] : true
                  : false;
            if (lineNums) { numberLines(cs, lineNums); }

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

    doWork();
  }

   /**
    * 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['prettyPrintOne'] = prettyPrintOne;
   /**
    * Pretty print a chunk of code.
    *
    * @param {string} sourceCodeHtml code as html
    * @return {string} code as html, but prettier
    */
  window['prettyPrint'] = prettyPrint;
   /**
    * Contains functions for creating and registering new language handlers.
    * @type {Object}
    */
  window['PR'] = {
        '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
      };
})();