On Mon, 15 Feb 2010 00:31:29 +0300, Walter Bright
<[email protected]> wrote:
Right now, mixins are defined and used as:
template foo(T) { declarations... }
mixin foo!(int) handle;
The proposal is to switch it around:
mixin template foo(T) { declarations... }
foo!(int) handle;
to follow the notion that mixin templates are very different from
regular templates, and that should be reflected in their definition
rather than use.
What do you think?
I support the change, expect that I believe mixing in the mixin template
should involve the "mixin" keyword.
In fact, I have proposed exactly the same more that a year ago. Here is a
quote:
Usually templates and mixin templates are completely
different, mixin'ing usual template or instantiating template that is
intended for being mixed-in makes no sense in the majority of real cases.
Moreover, I would prefer to separate these terms and so their syntax:
mixin template Bar
{
private int value;
public int getValue() { return value; }
}
class Foo
{
mixin Bar!();
}
int bar = Bar!().getValue(); // Error: can't instantiate mixin template
template Square(alias x)
{
private enum temp = x * x;
public enum Square = temp;
}
class Test
{
mixin Square!(42); // Error: can't mixin non-mixin template
}
