Unqual for @safe @system and @trusted

[Johannes Pfau]

Am 11.12.2010, 19:33 Uhr, schrieb bearophile <bearophileHUGS at lycos.com>:

> Johannes Pfau:
>
>> Is there something like Unqual that can remove the safety attributes  
>> from
>> a type?
>
> In such cases we have to ask what's your use case/purpose. Isn't  
> @trusted enough?
>
> Bye,
> bearophile

Well, for my signal implementation (Latest code: http://ideone.com/SM11K )  
I have templates which accept functions, delegates and callable objects. I  
used something like "static if(is(T == void delegate(int)))" to check if:
1. T is a delegate
2. it returns void
3. it takes one int parameter

In this case I'm only interested in these three points, I don't care if T  
is @safe @trusted or @system, but the above check fails if T is @safe.

I found a solution though, I now do these checks with functions from  
std.traits: ReturnType!(T) for the return type,  
is(typeof(T.init(Init!(Types)))) for parameters and is(T == delegate).  
Seems to work fine now.
-- 
Johannes Pfau