code: function _String_toInt(str)
  {
  	var total = 0;
  	var code0 = str.charCodeAt(0);
  	var start = code0 == 0x2B /* + */ || code0 == 0x2D /* - */ ? 1 : 0;
  
  	for (var i = start; i < str.length; ++i)
  	{
  		var code = str.charCodeAt(i);
  		if (code < 0x30 || 0x39 < code)
  		{
  			return __Maybe_Nothing;
  		}
  		total = 10 * total + code - 0x30;
  	}
  
  	return i == start
  		? __Maybe_Nothing
  		: __Maybe_Just(code0 == 0x2D ? -total : total);
  }
docs: INT CONVERSIONS