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);
}
signature.asc
Description: PGP signature
