Use case for std.bind
Yigal Chripun
dude at sweet.com
Tue Feb 24 10:34:30 PST 2009
Andrei Alexandrescu Wrote:
>
> I'd agree that generally there's a strong bias in this group for adding
> to the language. Every itsy-bitsy issue comes around, there are a dozen
> cute syntaxes invented for it right on the spot. And then once every few
> months, there's the inevitable huge thread "Where did my simple language
> go???" :o)
I disagree with this notion. there are requests to add new *useful* features but there are also requests to remove unneeded features, latest was the discussion of the implicit concatenation of string literals. There was a thread not long ago listing the features most people want to remove - foreach_reverse comes to mind.
that how evolution works - you add new useful stuff and remove old unneeded baggage. both are equally important.
> Currying/binding can be done easily with a library, and the
> implementation is so simple there's no need for a separate file
> dedicated to it. The one interesting case is currying a function passed
> by alias. In that case there's no indirect call, just a little struct
> created that contains the curried state:
>
> int plus(int x, int y} { return x + y; }
> auto plus5 = curry!(plus)(5);
> assert(plus5(10) == 15);
>
> typeof(plus5) will be a little struct that may be cumbersome to pass
> around, in which case you do want to take the toll of the indirect call
> by writing:
>
> auto plus5 = makeDelegate(curry!(plus)(5));
> assert(is(typeof(plus5) == int delegate(int));
> assert(plus5(10) == 15);
>
> This stuff belongs to std.functional. I plan to eliminate std.bind and
> put currying and binding in std.functional. What do people think?
>
> Andrei
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