At Sat, 4 Oct 2014 10:13:14 -0500,
Robby Findler wrote:
> That said, I do think that our integration of generic operations and
> our standard library deserves some more care and perhaps redesign to
> make things hang together better. As it stands, we have some
> conveniences, but they are limited b
Actually it's probably better, as it prevents ambiguity about which
predicates 'class-instance' should meet. Unlike 'class-instance', the
expression '(class-instance)' starts with no predicates, so making '(list?
(class-instance))' true won't disrupt anything else. Thus, you can be
explicit about w
I see your point. As a workaround, I suppose it's just as good to combine
these ideas and use `prop:procedure` to hook into the `get-list` method.
Then, instead of using 'class-instance' as a list, I can use
'(class-instance)',
and things like (member val (class-instance)) and (map proc
(class-inst
There is no prop:list like that.
Adding more prop:* features (like prop:list) has implications for code
that you cooperate with. In particular, when you get something that
answers #t to list?, then you can rest assured that calling 'car' or
it is a very simple operation (doesn't invoke unknown cod
Thank you. The `prop:procedure` works as hoped, in that the class instance
becomes usable in any form that takes a procedure (including things like
map).
The `prop:sequence` also works, but … what it seems I really want is
`prop:list`, which AFAICT doesn't exist (?)
The class I'm making is basica
I don’t know if you can do it with generic interfaces (as in racket/generic),
but you can make classes whose instances have struct-type properties such as
prop:procedure and prop:sequence
(using interfaces as in racket/class, not racket/generic)
#lang racket
(define proc<%>
(interface* ()
What's the best approach to:
+ defining a class whose instances can be used as procedures?
(define ci (new proc-class%))
(ci arg arg2 ... )
+ ... whose instances can be used as lists (or at least support direct
iteration?)
(define li (new listish-class%))
(for-each displayln li)
(map ci li)
M
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