Template mixins and selective imports

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On Thursday, 3 August 2017 at 15:29:47 UTC, jmh530 wrote:
> I am trying to create a vectorize function that mixes in a new 
> version of function with the same name that applies the 
> function (to an ndslice).
>
> The code below compiles without error and has the behavior I 
> would expect.
>
> However, when I change the function import to a selective 
> import (e.g. from import std.math; to import std.math : sin;), 
> then I get errors implying that the overload is not actually 
> created.
>
> Ideally, I would like to get this working with any kind of 
> import.
>
> One thing I noticed is that the fullyQualifiedName of sin 
> changes quite a bit depending on whether you use one or the 
> other.
>
> This may be related to either of the following:
> https://issues.dlang.org/show_bug.cgi?id=16287
> https://issues.dlang.org/show_bug.cgi?id=16023
>
>
>
> -----------------------------------
>
> import std.traits : isFunction;
>
> private enum _vectorize(string f) = "
>     import mir.ndslice.slice : SliceKind, Slice;
>
>     auto " ~ f ~ "(SliceKind kind, size_t[] packs, Iterator)
>                                            (Slice!(kind, packs, 
> Iterator) slice)
>     {
>         import mir.ndslice.topology : map;
>         return slice.map!(f);
>     }
> ";
>
> mixin template vectorize(alias f)
>     if (isFunction!f)
> {
>     mixin(_vectorize!(__traits(identifier, f)));
> }
>
> unittest
> {
>     import std.stdio : writeln;
>     import mir.ndslice.slice : sliced;
>     import mir.ndslice.topology : map;
>     import std.math; //import std.math : sin;
>
>     auto x = [0.0, 1.0, 2.0, 3.0].sliced;
>
>     auto y = x.map!(sin);
>     writeln(y);
>
>     mixin vectorize!(sin);
>     auto z = sin(x);
>     writeln(z);
> }

I'm not 100% certain, but I believe you have to bring the 
vectorized overload of sin into the overload set, so first try 
`mixin vectorize!sin vsin; alias sin = vsin;` and see if it works.

https://dlang.org/spec/function.html#overload-sets