code: function parse_matched (match, line) {
    var whole_match = match[0]
    var url_match = match[2]
    var start = match.index + whole_match.indexOf(url_match)
  
    return {
      start: start,
      end: start + url_match.length,
      match: url_match,
      line: line.line,
      column: start - line.index
    }
  }
docs: 0      -> url( "a.png" ) 1      -> " 2      -> a.png index input