This is a very long long shot...
We already have a parser, but it's hidden in C3 CON Tools and cannot be used directly. It is used by Setlist Manager and Quick Pack Editor. It is not really meant as a validator for DTA files, it will not tell you what is wrong with your DTA, but in some cases it may accidentally give you a hint.
To use it, open Setlist Manager, create an empty RB3/PS3 setlist, and drag-and-drop your DTA into it. A perfectly fine DTA will display songs in order by Artist.
Here are a few things I found by trying randomly:
- if a custom is missing the first "(", the setlist manager will show that custom first in the list
- if a custom has one or more extra ")", the setlist manager with first show all the custom which occur after the bad custom in the DTA
- if a custom has more "(" than ")" the setlist manager just shows all the correct customs before the bad custom
A couple of other possible errors might be visible after exporting to CSV, but make sure you select to export "everything":
- if a song is missing the ID, it will show up "0" in the "Song ID" column of the CSV
- if a song has missing duration, it will show up "0:00" in the "Duration" column of the CSV
- if a song has a bad path to the midi file, you can see it in the "File Path" column of the CSV (it should be always songs/filename/filename)
It's not much, but maybe in some cases it can give a quick hint.