> On Mar 31, 2017, at 1:00 PM, David Storrs <david.sto...@gmail.com> wrote: > > In Perl I can use caller() [1] to access the stack so that I can have _baz > report errors as though the error were coming from 'foo' or 'bar' as > appropriate -- which is what the user expects to see, since their code called > 'foo' or 'bar', not '_baz'. (Even better, I could report as though the error > were coming from the *caller* of foo / bar, which is the user's actual code > and the real source of the problem.)
An exception propagates upward through the calling chain. So rather than immediately using `raise-arguments-error` and launching it to the top, you could raise the error in two steps: 1) create a new error type (say, `(struct _baz-error (msg))`, so it has a unique predicate). You can also inherit from something in the `exn` hierarchy. 2) raise this error within `_baz`: `(raise (_baz-error "whoops"))` 3) catch the error within `foo` or `bar` using `with-handlers`: `(with-handlers ([_baz-error? (λ (exn) (handle-baz-error exn)]) ···)` Where `handle-baz-error` maybe re-raises the error with `raise-argument-errors` using the name of the current function. 4) Or following your "even better" idea, put the `with-handlers` in the caller of `foo` / `bar`. Here's an example of this approach: http://beautifulracket.com/basic-2/better-line-errors.html <http://beautifulracket.com/basic-2/better-line-errors.html> 5) You could extend this idea to more than two steps, where you collect other names in the calling chain on the way up. -- 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 racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
