showdownjs/src/subParsers/codeSpans.js

/**
 *
 *   *  Backtick quotes are used for <code></code> spans.
 *
 *   *  You can use multiple backticks as the delimiters if you want to
 *     include literal backticks in the code span. So, this input:
 *
 *         Just type ``foo `bar` baz`` at the prompt.
 *
 *       Will translate to:
 *
 *         <p>Just type <code>foo `bar` baz</code> at the prompt.</p>
 *
 *    There's no arbitrary limit to the number of backticks you
 *    can use as delimters. If you need three consecutive backticks
 *    in your code, use four for delimiters, etc.
 *
 *  *  You can use spaces to get literal backticks at the edges:
 *
 *         ... type `` `bar` `` ...
 *
 *       Turns to:
 *
 *         ... type <code>`bar`</code> ...
 */
showdown.subParser('codeSpans', function (text) {
  'use strict';

  /*
   text = text.replace(/
   (^|[^\\])					// Character before opening ` can't be a backslash
   (`+)						// $2 = Opening run of `
   (							// $3 = The code block
   [^\r]*?
   [^`]					// attacklab: work around lack of lookbehind
   )
   \2							// Matching closer
   (?!`)
   /gm, function(){...});
   */

  text = text.replace(/(^|[^\\])(`+)([^\r]*?[^`])\2(?!`)/gm, function (wholeMatch, m1, m2, m3) {
    var c = m3;
    c = c.replace(/^([ \t]*)/g, '');	// leading whitespace
    c = c.replace(/[ \t]*$/g, '');	// trailing whitespace
    c = showdown.subParser('encodeCode')(c);
    return m1 + '<code>' + c + '</code>';
  });

  return text;

});