On Thu, Sep 29, 2016 at 12:23:16PM -0400, Ryan Culpepper wrote: > > ; /tmp/test.rkt:29.0: my-let: expected the identifier `begin' > > ; at: quote > > ; in: (my-let ((x 5)) x) > > ; Context: .... > > ... > The `quote` is coming from the local expansion: ... > Meanwhile, you can also fall back to printf debugging using #:do > side-clauses. I did eventually figure out where the quote was coming from using printf debugging. The problem was I had no idea where to start, because in a larger context with more complex macros it is really unclear why "begin" was expected but "quote" was found in the expression "(my-let ((x 5)) x)", which does not contain "quote" and does not use "begin" at the top-level pattern. I think I would have had a lot less trouble debugging if the error message had said something about a "#:with" pattern, or something that indicated it wasn't expected in the "(my-let ((x 5)) x)" directly but in some refinement of the pattern.
> Would something like `debug-syntax-parse!` extended with Alex's proposal > (https://github.com/racket/racket/issues/1377) for more debugging information > have helped? That looks great. Although, I also didn't know about "debug-syntax-parse!". > > ; /tmp/test.rkt:29.0: my-let: expected the identifier `lambda > > ; at: lambda > > ; in: (my-let ((x 5)) x) > > ; Context: .... > > > >So, we expected to see identifier that is there? > >That's a strange error. ... > I'll see if I can squeeze it into the error message that the identifier was > expected to have a different binding. I think this is an instance of larger problem; I ran into a similar problem with #%plain-app being printed as #%app, and only now understand (thanks Alex!) what's really going on here. I don't think it's specific to syntax-parse. -- William J. Bowman -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
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