| Subject: | Provide a means to return a custom failure message from callback validation |
I would like to be able to supply a message describing why a particular callback function failed to validate. I understand that this might be problematical given that the existing true/false mechanism precludes simply returning a string.
As an example, if I were validating a list of user IDs, I might want to return a msg that said "ID's xxxx, yyyy and zzzz are not valid users" instead of returning a 0 (or undef) and having the caller see the generic callback failed message.
Conceivably this might be accomplished by being able to "die" within a callback with a suitable message and that be used. This might be somewhat easier in the PP version, but I would not be surprised to hear that the XS version would present a challenge.