Parsers.rep() hides failures

[gzoller]

I noticed an issue reported here in stackoverflow: here

Curious, I looked up the code for rep() and noticed this simple one-liner:

def rep[T](p: => Parser[T]): Parser[List[T]] = rep1(p) | success(List())

Hmm. This looks like it repeats but upon a failure just returns success(List()), which seems to match my observed behavior. Am I reading this correctly?

If so... then this hides the failure. If in 'p' I've returned a failure, the associated message is swallowed, and my calling program has no idea whether 1) parsing fully succeeded or 2) parsing partially succeeded, and if #2 then why it failed.

Are there circumstances when swallowing the failure is a desirable thing?

[gzoller]

Never mind. I see that it propagates err(), but not failure(). Failure just tells rep() that its done repeating, while err() tells it something broke.