Re: [boost] Quick q on simple type manipulation helpers

From: Douglas Gregor (gregod_at_[hidden])
Date: 2001-11-20 12:39:27

On Tuesday 20 November 2001 10:49 am, you wrote:
> > For instance I don't like those macros to
> > define typelists.
>
> I am looking forward to hear about better solutions. For the record, I made
> a very offensive comment about the preprocessor already :o).

  TYPELIST_5(T1, T2, T3, T4, T5) 
becomes 
  make_type_list<T1, T2, T3, T4, T5>::type

make_type_list is defined as:

template<
  typename T1 = null_type,
  typename T2 = null_type,
  ...
  typename T50 = null_type
>
struct make_type_list {
  // build a typelist from T1..T50, eliminating extra null_types from the 
  //  list. Call the final typelist "type"
};

Boost.Tuples does this.

        Doug