C. Scott Ananian wrote:
On Tue, May 19, 2015 at 12:24 PM, Steve Fink <[email protected]
<mailto:[email protected]>> wrote:
That visually collides with destructuring for me.
let [a, b] = foo();
let {a, b} = foo();
let f(a, b) = foo(); # Very different
I almost expect that last one to use f as a custom matcher of some
sort, given the previous two.
Well *there's* an interesting proposal. As I understand it, this
corner of the grammar is free, so custom matchers would be a
possibility here.
I can imagine some interesting uses for custom data types, eg:
let pair(a, b) = foo(); // like `let {head, tail} = foo();` but with
custom type checking.
let polar(radius, angle) = point(1, 2); // custom matcher can convert
between coordinate respresentations
or even build a simple matching case statement for a recursive decent
parser:
let for_statement(init, cond, incr) = input_text;
Does that spark ideas in anyone else?
Sure, and we've had pattern matching on the agenda for a while (distinct
from destructuring in ES6: refutable match, richer pattern language).
http://wiki.ecmascript.org/doku.php?id=harmony:refutable_matching
(arossberg: anything newer on github?)
http://wiki.ecmascript.org/doku.php?id=strawman:pattern_matching (older
strawman from dherman)
I agree that `let f(x) = y` encroaches confusingly on pattern matching,
not let-function declaration.
/be
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