I believe this would be a reasonable concise synchronous generator someone
could write:
```js
const concat = (a, b) =*> { yield* a; yield* b; }
```
________________________________
From: Kevin Smith<mailto:[email protected]>
Sent: 12/12/2013 15:17
To: Mark S. Miller<mailto:[email protected]>
Cc: Brendan Eich<mailto:[email protected]>;
es-discuss<mailto:[email protected]>
Subject: Re: Reserving await within Arrow Functions
p2 = p1 ! foo(a, b);
would be equivalent to
p2 = Promise.cast(p1).send("foo", a, b);
which, for local promises, is equivalent to the ES6
p2 = Promise.cast(p1).then(r => r.foo(a, b));
Yes, but "!" isn't agreed upon. By that time, we might be over our
CoffeeScript-inspiration long enough to consider thin arrows. After all, thin
arrows are used for a different kind of indirection in C. Maybe...
Actually, they do. Thanks to Domenic for triggering the following thought:
Where
x => t
implements the mapping type X -> T, the corresponding
x =*> t
implements the mapping type X -> T*, where the "*" here reads like the kleene
(or regexp) *, i.e., this function maps from an X to zero or more Ts.
Exactly. That's my point, essentially. The design niche for arrows is
expressing simple surjections (with side-effects of course), not one-to-many
relationships.
Concise synchronous generators.
Restating the feature isn't exactly demonstrating a use case : ) Is there a
concrete example which would give us some idea of the benefit of arrow
generators?
It's difficult because we don't have much data yet. But that lack of data is
another argument for reserving await, I think.
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