Re: Strange Mixin issue

[Ali Çehreli]

On 03/05/2014 01:30 PM, Frustrated wrote:
I am trying to remove the unnecessary passing of the type of class to a
template but can't seem to get it to work:
see



The code is the


     mixin(AbstractToInterface!(WindowsGui, iButton, WindowsButton,
iBorder, WindowsBorder));

which I want to not have to specify WindowsGui.

I've tried wrapping AbstractToInterface in a mixin template and use that
and typeof(this) but then the mixin of the mixin does not get mixed in
to the class

e.g.,

mixin template AbstractToInterface2(T...)
{
     mixin(AbstractToInterface!(typeof(this), T));
}

Then use mixin AbstractTointerface2!(iButton, WindowsButton, iBorder,
WindowsBorder).

It's probably something stupid but I can't seem to get it to work(have a
very similar case in some other code and it works fine... the only
difference is I'm not using nested mixins.


The following works for me maybe because the templates are not mixin 
templates. What's a mixin template again?

import std.typetuple;

template fooImpl(This, T...)
{
    static assert(is (This == S));        // <-- IT WORKED!
    static assert(is (T == TypeTuple!(int, double)));
}

template foo(T...)
{
    alias foo = fooImpl!(typeof(this), T);
}

struct S
{
    mixin foo!(int, double);
}

void main()
{
    auto s = S();
}

Even better:

import std.typetuple;

template fooImpl(T...)
{
    static assert(is (T[0] == S));    // <-- COOL!
    static assert(is (T[1] == int));
    static assert(is (T[2] == double));
}

template foo(T...)
{
    alias foo = fooImpl!(TypeTuple!(typeof(this), T));
}

struct S
{
    mixin foo!(int, double);
}

void main()
{
    auto s = S();
}

Ali