Using D2: given a template with parameter T, how do you strip away const/invariant from the type T in an overload without creating a separate overload for each and every possible type?

What I'm looking for is something like:

T strip( T )( T arg )
{
    return arg;
}

T strip( T: const T )( const T arg )
{
    return cast(T) arg;
}

T strip( T: invariant T )( invariant T arg )
{
    return cast(T) arg;
}

The above doesn't work but should be enough to show what I'm asking.
Thanks,
Brian

On Mon, 29 Sep 2008 19:38:42 +0000 (UTC), Brian Price
<blprice61@yahoo.com> wrote:

>Using D2: given a template with parameter T, how do you strip away const/invariant from the type T in an overload without creating a separate overload for each and every possible type?
>
>What I'm looking for is something like:
>
>T strip( T )( T arg )
>{
>    return arg;
>}
>
>T strip( T: const T )( const T arg )
>{
>    return cast(T) arg;
>}
>
>T strip( T: invariant T )( invariant T arg )
>{
>    return cast(T) arg;
>}
>
>The above doesn't work but should be enough to show what I'm asking.
>Thanks,
>Brian

Your example doesn't work because of a compiler bug. You could use std.traits.Mutable template or its implementation:

import std.traits;

auto strip(T)(T arg)
{
    return cast(Mutable!(T)) arg;
}

or

auto strip(T)(T args)
{
    static if (is(T U == const(U)) || is(T U == invariant(U)))
        return cast(U) args;
    else
        return args;
}

On Tue, 30 Sep 2008 09:49:26 +0300, Max Samukha <samukha@voliacable.com.removethis> wrote:

>On Mon, 29 Sep 2008 19:38:42 +0000 (UTC), Brian Price
><blprice61@yahoo.com> wrote:
>
>>Using D2: given a template with parameter T, how do you strip away const/invariant from the type T in an overload without creating a separate overload for each and every possible type?
>>
>>What I'm looking for is something like:
>>
>>T strip( T )( T arg )
>>{
>>    return arg;
>>}
>>
>>T strip( T: const T )( const T arg )
>>{
>>    return cast(T) arg;
>>}
>>
>>T strip( T: invariant T )( invariant T arg )
>>{
>>    return cast(T) arg;
>>}
>>
>>The above doesn't work but should be enough to show what I'm asking.
>>Thanks,
>>Brian
>

>auto strip(T)(T args)
>{
>    static if (is(T U == const(U)) || is(T U == invariant(U)))
>        return cast(U) args;
>    else
>        return args;
>}
args was meant to be arg

The std.traits.Mutable solution is exactly what I needed.
Thanks,
Brian