Map destructuring intended behavior?

[Mike Drogalis]

Problem statement: Map destructuring rules are inconsistent depending on the value of the keywords of the map.

Example: https://gist.github.com/MichaelDrogalis/6020235

I understand why the error message is what it is, but would it be appropriate for map destructuring to permit the slash inside a symbol for the sake of consistency?

[Alex Miller]

That doesn't make sense to me - destructuring creates locally scoped names which are not allowed to be namespaced, so I don't think this is something that should be allowed. 

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[Softaddicts]

+1, strictly local,
Luc

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Softaddicts<lprefo...@softaddicts.ca> sent by ibisMail from my ipad!

[Mike Drogalis]

Makes sense. Thanks guys.

[Chouser]

I actually would really like to be able to use :keys to bind
namespaced keywords to local names. This would be exceedingly handy
for example when working with datomic data.

I would want this:
(let [{:keys [a/x]} {:a/x 5}]
x)
;=> 5

That is, you would fully qualify the symbol name in the :keys vector,
but the local bound to it would remain local and unqualified.

There would of course be the potential for keys that could not be
bound this way, for example if the map was {:a/x 5, :b/x 10}. But we
already have this kind of problem for example when using both :strs
and :keys and a map like {:x 5, "x" 10}. In practice this is rarely an
issue, and when it comes up you simply have to use the more verbose
destructuring.

What do you think?

--Chouser

[Mike Drogalis]

The Datomic scenario is the reason I posted this. Sorry about failing to mention that.

[Thomas Heller]

You can already destructure namespaced keys? Just not via :keys, slightly more code but still nice.

(let [{my-x :a/x :keys [a b] :as m} {:a/x 1 :a 4}] my-x)

Cheers,

/thomas

[Alex Miller]

I believe that's the "more verbose destructuring" Chouser referred to.