core.async

Provide a chan? function to determine if a given var is a channel

Details

  • Type: Enhancement Enhancement
  • Status: Open Open
  • Priority: Major Major
  • Resolution: Unresolved
  • Affects Version/s: None
  • Fix Version/s: None
  • Component/s: None
  • Labels:
    None

Description

When using channels, for example for streaming http bodies, it would be really helpful if there would be a chan? function to check whether a given var is a channel or not.

Aleph already does it like that in it's http-server/client implementation using lamina channels and it feels quite consistent.

It would of course also be more consistent with the rest of clojure to provide a type checking function for basic objects.

Activity

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David Rupp added a comment - - edited

Implement chan? predicate.

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David Rupp added a comment - - edited Implement chan? predicate.
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Timothy Baldridge added a comment -

I'm in favor of this, but last time I asked Rich about it his quote was "do you want a predicate for every single interface?".

Due to the implementation of core.async you'd probably need two additional predicates. One for read-port? and write-port?. You can use (satisfies? clojure.core.async.impl.protocols/ReadPort ...) but that's an internal implementation, so I'd rather have a new predicate than to tell people to touch the innards of core.async. But this call is up to Rich.

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Timothy Baldridge added a comment - I'm in favor of this, but last time I asked Rich about it his quote was "do you want a predicate for every single interface?". Due to the implementation of core.async you'd probably need two additional predicates. One for read-port? and write-port?. You can use (satisfies? clojure.core.async.impl.protocols/ReadPort ...) but that's an internal implementation, so I'd rather have a new predicate than to tell people to touch the innards of core.async. But this call is up to Rich.
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Reno Reckling added a comment -

I understand that reasoning. But then we would have to step up on documentation and provide a way to easily determine which interfaces are implemented by the return values of for example (chan). For me, going into the innards of core.async and trying to determine which interfaces I want, especially on very basic things like a channel, is not a user friendly approach at all.

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Reno Reckling added a comment - I understand that reasoning. But then we would have to step up on documentation and provide a way to easily determine which interfaces are implemented by the return values of for example (chan). For me, going into the innards of core.async and trying to determine which interfaces I want, especially on very basic things like a channel, is not a user friendly approach at all.
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Thomas Heller added a comment -

I would like to see the mentioned chan? read-port? write-port? predicates as they would make writing some clojure.spec/fdefs simpler (and portable to cljs.core.async).

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Thomas Heller added a comment - I would like to see the mentioned chan? read-port? write-port? predicates as they would make writing some clojure.spec/fdefs simpler (and portable to cljs.core.async).

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Dates

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    Updated:
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