Need trait of isPod.

[Lutger]

Aarti_pl wrote:
> Matti Niemenmaa pisze:
...
>> That misses structs, which are also POD.
>>
> 
> It should be just enough to add additional condition:
> 
>     (...)
>     || is( T == struct )
>     (...)
> 
> and also probably union and enum.
> 
> More:
> http://digitalmars.com/d/expression.html  (section: is expression)
> 
> 
> BR
> Marcin Kuszczak
> (aarti_pl)

Correct me if I'm wrong, but I thought POD requires members of a struct 
be public and also POD.
Here is a version (quick hack) that takes these criteria into account 
(D1.0 syntax):

template isAtomicType( T ) {
     static if( is( T == bool )
             || is( T == char )
             || is( T == wchar )
             || is( T == dchar )
             || is( T == byte )
             || is( T == short )
             || is( T == int )
             || is( T == long )
             || is( T == ubyte )
             || is( T == ushort )
             || is( T == uint )
             || is( T == ulong )
             || is( T == float )
             || is( T == double )
             || is( T == real )
             || is( T == ifloat )
             || is( T == idouble )
             || is( T == ireal ) )
         const isAtomicType = true;
     else static if (is(T == struct))
     {
         static if (is (typeof(T.tupleof))) // test for private members
         {
             static if (T.tupleof.length == 0)
                 const isAtomicType = true;
             else
                 const isAtomicType = areAtomicTypes!(typeof(T.tupleof));
         }
         else
             const isAtomicType = false;
     }
     else
        const isAtomicType = false;
}

// helper template
template areAtomicTypes(T...)
{
     static if (T.length == 1)
         const areAtomicTypes = isAtomicType!(T[0]);
     else
         const areAtomicTypes = isAtomicType!(T[0]) && 
areAtomicTypes!(T[1..$]);
}