How to use map?
Lemonfiend via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Tue Nov 11 11:24:29 PST 2014
On Tuesday, 11 November 2014 at 15:53:37 UTC, Marc Schütz wrote:
> Don't know whether it's documented, but it's a consequence of
> using string mixins.
>
> unaryFun (which is used internally by map) is implemented this
> way:
>
> auto unaryFun(ElementType)(auto ref ElementType __a)
> {
> mixin("alias " ~ parmName ~ " = __a ;");
> return mixin(fun);
> }
>
> where `fun` is `Foo(a)`. Of course, `Foo` is not visible in
> std.functional. When you pass in a symbol, the lookup work
> because it takes place at the point of instantiation.
That makes sense, thanks.
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