2012/4/30 Asumu Takikawa <[email protected]>:
> On 2012-04-29 12:43:48 -0400, Matthias Felleisen wrote:
>> What you're really saying is that sequence-map uses the wrong kind of type.
>> Specifically, it should be polymorphic in the sequence constructor instead
>> of mapping everything to the top of the class hierarchy (sequence).
>
> I don't think this is just a type issue. The sequence that is returned
> by `sequence-map` is lazy, even if the original sequence was not. That's
> why you can't get the original type.
Good point.
However, I don't mind doing some manual labor:
(define (map-sqr a-sequence)
(let ([construct (sequence-constructor a-sequence)])
(apply construct (sequence->list (sequence-map sqr a-sequence)))))
(map-sqr '(1 2 3)) ; => (1 4 9)
(map-sqr #(1 2 3)) ; => #(1 4 9)
--
Jens Axel Søgaard
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