Re: [boost] Submission: typelist

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2001-11-26 17:29:38

Unfortunately, that sounds like a name for a compile-time predicate.
----- Original Message -----
From: <wb_at_[hidden]>

> Just as another source of ideas for these important constructs,
> I attach a lightly-edited excerpt from SIunits' "metatypes" header
> for consideration.
>
> - WEB
>
>
> // ----------  begin excerpt  ----------
>
> namespace meta  {
>
> template< class T >
> struct type_is  // previous names: type_wrapper, my_type
> {
>   typedef  T  type;
> }
>
> template< class T, T v >
> struct value_is  // previous names: value_wrapper, my_value
>   : public type_is<T>
> {
>   static  T const  value = v;
> }
>
> }  // namespace meta
>
> // ----------  end excerpt  ----------
>
>
> David Abrahams <david.abrahams_at_[hidden]> wrote on Mon Nov 26 15:36:16 2001:
>
> | Too bad we can't overload compile-time functions; then we could have
> | identity<10>::value == 10 and identity<char>::type == type.
> |
> | Maybe value_identity is best... leading to type_identity for symmetry
:-/
> |
> | ----- Original Message -----
> | From: "joel de guzman" <djowel_at_[hidden]>
> |
> | > ----- Original Message -----
> | > From: "Andrei Alexandrescu" :
> | >
> | > > From: "David Abrahams" <david.abrahams_at_[hidden]>
> | > > > BTW, isn't "identity" a much better name than "type2type"?
> | > >
> | > > Identity sounds great, I'll make that change unless there is a lot
of
> | > > opposition.
> | >
> | > identity is cool!
> | >
> | > int2type and type2type are quite, umm, unclear.
> | >
> | > How about static_int<N> instead of int2type<N> ? Syntactically, It's
like
> | > static_cast that transforms an int to a distinct static-integer type.
> | >
> | > Or maybe, how about: int_identity<N> ?
> <snip>
>
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