Re: Template mixin enum stringof

[Lemonfiend via Digitalmars-d-learn]

On Wednesday, 10 December 2014 at 14:25:30 UTC, ketmar via 
Digitalmars-d-learn wrote:
On Wed, 10 Dec 2014 13:58:20 +0000
Lemonfiend via Digitalmars-d-learn 
<digitalmars-d-learn@puremagic.com>
wrote:
On Wednesday, 10 December 2014 at 12:57:16 UTC, ketmar via 
Digitalmars-d-learn wrote:
> On Wed, 10 Dec 2014 12:35:44 +0000
> Lemonfiend via Digitalmars-d-learn 
> <digitalmars-d-learn@puremagic.com>
> wrote:
>
>> On Wednesday, 10 December 2014 at 12:08:34 UTC, ketmar via 
>> Digitalmars-d-learn wrote:
>> > On Wed, 10 Dec 2014 11:52:11 +0000
>> > Lemonfiend via Digitalmars-d-learn 
>> > <digitalmars-d-learn@puremagic.com>
>> > wrote:
>> >
>> >> Consider the following:
>> >> 
>> >> ---
>> >> enum Foo { BAR, }
>> >> 
>> >> mixin template S(string s_)
>> >> {
>> >>       enum s = s_;
>> >> }
>> >> 
>> >> void main()
>> >> {
>> >> 	mixin S!(Foo.BAR.stringof); // Error: identifier 
>> >> 'stringof' of 'Foo.BAR.stringof' is not defined
>> >> 
>> >> 	enum e = Foo.BAR.stringof;
>> >>       mixin S!(e); // works fine
>> >> }
>> >> ---
>> >> 
>> >> Why doesn't the first work? And is there an alternative 
>> >> to the second version?
>> >
>> >   mixin S!((Foo.BAR).stringof);
>> >
>> > sorry, don't remember the parsing rule for this.
>> 
>> Wow, I didn't even consider that.. Thanks!
> also, you can use this:
>
>   import std.conv : to;
>   ...
>   mixin S!(to!string(Foo.BAR));
>
> people tend to forget that many `to!` variants are usable in 
> CTFE.

Seems like I'd want to move the converting-to-string 
functionality to within the template mixin then, something 
like:

---
mixin template S(T, T t) if (is(T == enum))
{
        //import std.traits;
	//enum s = fullyQualifiedName!(t); // unfortunately this 
results in "t"

        import std.conv: to;
        enum s = to!string(t); // this works
}

mixin S!(Foo, Foo.BAR);
---

But passing an enum as parameter seems to be somewhat 
annoying. If I leave off the first Foo, then it complains 
about no-matching template for int parameter.
!(Foo, Foo.BAR) seems kinda redundant..
something like this?

  mixin template S(alias fld) if (is(typeof(fld) == enum))
  {
    import std.conv : to;
    enum s = to!string(fld); // "BAR"
    // or this:
    //import std.traits : fullyQualifiedName;
    //enum s = to!string(fullyQualifiedName!(fld)); // 
"test.Foo.BAR"
  }

  enum Foo { BAR, }

  void main()
  {
    mixin S!(Foo.BAR);
  }

Perfect, thanks.