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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/8306c09e-4d2b-46c7-945a-1ac1a7054fddn%40googlegroups.com.
