[boost] Re: An alternative typeof macro

From: Daniel James (daniel_at_[hidden])
Date: 2004-09-02 04:43:36

I've been trying out your new version, and I found that it was fairly 
easy to run out of indicies when using it repeatedy. Looking at the 
code, I think it should be possible to only generate one value per 
encoding. Basically my idea is that instead of using:

     friend sizer<VOLATILE> encode_value(encode_counter<Index>*);

You could use:

     template<unsigned EncodingId, unsigned Index = 0>
     struct value_pair
     {
         typedef value_pair<EncodingId, Index+1> next;
     };

     friend sizer<VOLATILE> encode_value(value_pair<EncodingId, Index>*);

The existing compile time variable mechanism would just be used to 
generate the increasing EncodingId's - one per typedef. I included the 
next member so that the value_pair could be passed by type, replacing 
the existing Index parameter. Then whenever you currently use Index+1, 
you can use 'typename ValuePair::next'.

I guess this is a little obvious, so sorry if you're already doing 
something like it. If it doesn't make sense I can put together an 
implementation.

Daniel