Object.extend(String.prototype, {
  gsub: function(pattern, replacement) {
    var result = '', source = this, match;
    replacement = arguments.callee.prepareReplacement(replacement);
    
    while (source.length > 0) {
      if (match = source.match(pattern)) {
        result += source.slice(0, match.index);
        result += (replacement(match) || '').toString();
        source  = source.slice(match.index + match[0].length);
      } else {
        result += source, source = '';
      }
    }
    return result;
  },
  
  sub: function(pattern, replacement, count) {
    replacement = this.gsub.prepareReplacement(replacement);
    count = count === undefined ? 1 : count;
    
    return this.gsub(pattern, function(match) {
      if (--count < 0) return match[0];
      return replacement(match);
    });
  },
  
  scan: function(pattern, iterator) {
    this.gsub(pattern, iterator);
    return this;
  },
  
  truncate: function(length, truncation) {
    length = length || 30;
    truncation = truncation === undefined ? '...' : truncation;
    return this.length > length ? 
      this.slice(0, length - truncation.length) + truncation : this;
  },

  strip: function() {
    return this.replace(/^\s+/, '').replace(/\s+$/, '');
  },
  
  stripTags: function() {
    return this.replace(/<\/?[^>]+>/gi, '');
  },

  stripScripts: function() {
    return this.replace(new RegExp(Prototype.ScriptFragment, 'img'), '');
  },
  
  extractScripts: function() {
    var matchAll = new RegExp(Prototype.ScriptFragment, 'img');
    var matchOne = new RegExp(Prototype.ScriptFragment, 'im');
    return (this.match(matchAll) || []).map(function(scriptTag) {
      return (scriptTag.match(matchOne) || ['', ''])[1];
    });
  },
  
  evalScripts: function() {
    return this.extractScripts().map(function(script) { return eval(script) });
  },

  escapeHTML: function() {
    var div = document.createElement('div');
    var text = document.createTextNode(this);
    div.appendChild(text);
    return div.innerHTML;
  },

  unescapeHTML: function() {
    var div = document.createElement('div');
    div.innerHTML = this.stripTags();
    return div.childNodes[0] ? div.childNodes[0].nodeValue : '';
  },
  
  toQueryParams: function() {
    var pairs = this.match(/^\??(.*)$/)[1].split('&');
    return pairs.inject({}, function(params, pairString) {
      var pair = pairString.split('=');
      params[pair[0]] = pair[1];
      return params;
    });
  },
  
  toArray: function() {
    return this.split('');
  },
  
  camelize: function() {
    var oStringList = this.split('-');
    if (oStringList.length == 1) return oStringList[0];
      
    var camelizedString = this.indexOf('-') == 0
      ? oStringList[0].charAt(0).toUpperCase() + oStringList[0].substring(1) 
      : oStringList[0];
      
    for (var i = 1, len = oStringList.length; i < len; i++) {
      var s = oStringList[i];
      camelizedString += s.charAt(0).toUpperCase() + s.substring(1);
    }
    
    return camelizedString;
  },

  inspect: function() {
    return "'" + this.replace(/\\/g, '\\\\').replace(/'/g, '\\\'') + "'";
  }
});

String.prototype.gsub.prepareReplacement = function(replacement) {
  if (typeof replacement == 'function') return replacement;
  var template = new Template(replacement);
  return function(match) { return template.evaluate(match) };
}

String.prototype.parseQuery = String.prototype.toQueryParams;

var Template = Class.create();
Template.Pattern = /(^|.|\r|\n)(#\{(.*?)\})/;
Template.prototype = {
  initialize: function(template, pattern) {
    this.template = template.toString();
    this.pattern  = pattern || Template.Pattern;
  },
  
  evaluate: function(object) {
    return this.template.gsub(this.pattern, function(match) {
      var before = match[1];
      if (before == '\\') return match[2];
      return before + (object[match[3]] || '').toString();
    });
  }
}
