Hi, I'd like missing values (NAs) *a la R* in sequences, such as a `bit-vector` with a 3rd NA value (therefore taking 2 bits/element and not 1). I'd like that for integers, flonums, etc. too. I'm trying to make a (struct seq/na (mask data)) with prop:sequence, separating the NA mask from the sequence elements and design `for` forms to iterate on those. Trying to follow the prop:sequence and for/fold/derived examples, I tried:
(struct bit-vector/na (missing bits) #:property prop:sequence (λ (i j) (in-parallel (bit-vector/na-missing i) (bit-vector/na-bits j)))) but that failed with: ../../../../usr/share/racket/collects/racket/private/for.rkt:488:5: sequence-property-guard: contract violation expected: (procedure-arity-includes/c 1) given: #<procedure:.../in-memoriam.rkt:34:2> I understand the sequence interface is designed to consume a single element per iteration, but is there a way to achieve what I'd like? Thanks! Raoul -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/8306c09e-4d2b-46c7-945a-1ac1a7054fddn%40googlegroups.com.
