[m-users.] Determinism issue with parser
post at volker-wysk.de
Mon Jul 5 01:21:07 AEST 2021
Am Sonntag, den 04.07.2021, 14:17 +0100 schrieb Sean Charles
> I parse a file into a stream of tokens, there can be only one correct way
> to parse those into a well formed program. One. So the ast builder either
> fails or it doesnt, that is trapped in the code and a maybe_error is
> handed back, hence I figure the predicate, as seen by the caller (the REPL
> atm) should be `det`.
I've built a big parser for my project, too. It should always produce one
solution; it can't fail. But the compiler can't infer that it is
deterministic, for many parts of it. (That would be undecidable.)
So I've resigned to this state of affairs. I just collect all the (exactly
one) solutions with solutions/2 and produce an error message in case there
should be more than one, which would be a bug in my parser.
So maybe this would be the way to go for you, too.
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