# useful error message

    Code
      json2(input)
    Error <jsontools_error_invalid_json>
      invalid JSON at 12 locations:
        2, 4, 6, 8, 10, ..., 16, 18, 20, 22, 24
      
      2: offset 1
      parse error: premature EOF
                                             {"a": 1
                           (right here) ------^
      
      4: offset 1
      parse error: premature EOF
                                             {"a": 1
                           (right here) ------^
      
      6: offset 1
      parse error: premature EOF
                                             {"a": 1
                           (right here) ------^
      
      8: offset 1
      parse error: premature EOF
                                             {"a": 1
                           (right here) ------^
      
      10: offset 1
      parse error: premature EOF
                                             {"a": 1
                           (right here) ------^
      
      ... (7 more errors)

