__traits so long and ugly, what about ::?

[Alix Pexton]

On 30/03/2011 20:28, Ary Manzana wrote:
> I think :: is not used in the language.
>
> In a recent article about D I saw:
>
> mixin(__traits(identifier, T) ~ " " ~
> to!string(tolower(__traits(identifier, T)[0])) ~
> __traits(identifier, T)[1..$] ~ ";");
>
> What if foo::bar were an alias for __traits(foo, bar) ?
>
> The code would look like this:
>
> mixin(T::identifier ~ " " ~
> to!string(tolower(T::identifier[0])) ~
> T::identifier[1..$] ~ ";");
>
> What do you think?
>
> Another uses:
>
> __traits(int, isArithmetic) ==> int::isArithmetic
> __traits(C, isAbstractClass) ==> C::isAbstractClass
>
> __traits(hasMember, S, "m") ==> S::hasMember("m")
>
> Well, you get the idea...
>
> :: might be applied to other compile time uses, but I just came up with
> this...

Hmn, interesting idea! I noticed, however, that the "foo" and "bar" in 
your example are actually swapped...

__traits(foo, bar) ==> foo::bar

should be

__traits(foo, bar) ==> bar::foo

For many the uses of __traits I can recall off the top of my head, it 
certainly seems to be both elegant and intuitive. One sore thumb would 
be __traits(compiles, ...) which I believe gets used quite frequently in 
Phobos.

Clarifications and my lack of insight into the complete breadth of 
__traits's capabilities and variations aside, I think this is the best 
suggestion for the replacement of the much maligned experimental keyword 
that I have seen posted since Don's suggestion of a magic namespace[1]. 
I'm not 100% sure if this :: syntax could also tidy up is() expressions 
too, but if it can, I can imagine it having a lot of support. If 
language design was a democracy, I'd certainly vote for it ^^

A...

[1] Search the NG for "Proposal: Replace __traits and is(typeof(XXX)) 
with a 'magic namespace'."