function parse(strnum) {
    switch (strnum) {
      case 'NaN':case 'Infinity':case '-Infinity':
        return null;
    }

    var match = strnum.match(NUMBER_PATTERN);

    if (!match) {
      throw new Error('cannot round malformed number: ' + strnum);
    }

    return [match[1] !== undefined, match[2], match[3] || ''];
  }
Parses the given decimal string into its component parts.

@example

  stround.parse('3.14');  // [false, '3', '14']
  stround.parse('-3.45'); // [true, '3', '45']

@param {string} strnum
@return {?Array}