Destructuring
lantiga opened this issue · comments
Consider introducing destructuring.
I'm very interested in this feature. How complex do you think it would be to implement in terms of sweet.js macros/rules?
Got this
(let [[a [b] c [[d e] f]] [1 [2] 3 [[4 5] 6]]]
(add a b c d e f))
=> 21
working with this 5fd812b commit (works only for nested vector in a let form). It's a start, I'm quite impressed at how little code it took with sweet.js.
And here's fe371c0 destructuring of maps (mixed with vectors) in let forms:
(let [{[a] :a b :b} {:a [1] :b 2}]
[a b])
=> [1 2]
Well, that does it (for mori data structures and literals - we could probably consider adding destructuring with js array and object literals [$ ] {$ }, we'll see about it).
Now I have to figure out how to call the _destr macro in
- function signatures (single and multiple arity)
- loop forms
- letc (this one has some kind of hard-coded destructuring in a list, it could actually be left alone since it's the only destructuring that should be supported here)
Anywhere else?
From [http://clojure.org/special_forms#Special Forms--Binding Forms (Destructuring)](http://clojure.org/special_forms#Special Forms--Binding Forms %28Destructuring%29):
Clojure supports abstract structural binding, often called destructuring, in let binding lists, fn parameter lists, and any macro that expands into a let or fn.
So I think your list had it covered. I have mixed feelings about letc, it's probably really useful for Node.js-style APIs, but does it belong in core? Not that it's expensive to have it there, though.
Destructuring JS arrays/objects sounds interesting (and would actually give ki an edge over vanilla cljs), but probably not high-priority for now :)
Great, thanks for the quote - somehow it didn't occur to me that I could check on the Clojure website.
I feel the same way as you do about letc. It's possibly a nice to have, but it could indeed belong to an external macro library if we have enough of them at some point.
As for the JS arrays/objects destructuring, I just added it: 6ac7006