Hi, stefan <stefan.ta...@spray.se> writes:
> On Wednesday 21 April 2010 10:40:29 am Ludovic Courtès wrote: >> As noted in Shinn’s match-cond-expand.scm, this record matching form is >> not ideal: >> >> ;; Annoying unhygienic record matching. Record patterns look like >> ;; ($ record fields...) >> ;; where the record name simply assumes that the same name suffixed >> ;; with a "?" is the correct predicate. >> > > Entering, > > scheme@(guile-user)> (macroexpand '(n? x)) > (if (struct? x) (eq? (struct-vtable x) n) #f) That’s an implementation detail that you should ignore. :-) Just have users write: (($ n? a b c) ...) Where ‘n?’ is bound to the record type predicate, and have ‘match’ invoke that record type predicate. Thanks, Ludo’.
