[boost] Re: Named params library and BGL

From: Daniel Wallin (dalwan01_at_[hidden])
Date: 2004-04-17 06:16:44

Vladimir Prus wrote:

> Daniel Wallin wrote:
>>   template<class G, class A0, .., class AN>
>>   typename enable_if_graph<
>>       G
>>     , typename graph_traits<G>::edge_descriptor
>>   >::type
>>   add_edge(
>>       typename graph_traits<G>::vertex_descriptor u
>>     , typename graph_traits<G>::vertex_descriptor v
>>     , A0 const& a0
>>     , ...
>>     , AN const& an
>>     , G& g)
>>   {
>>       typename keywords_for_graph<G>::type kw;
          ^^^^^^^^                             ^^
>>       return add_edge_impl(u, v, g, kw(a0, ..., an));
> 
> 
>    Should there be kw()(a0...) ? It seems the syntax that works for me.

No, kw isn't a type here.

[snip]
> I wonder what's the reason to require conversion/construction of keywords<>?
> Couldn't (color = 10, name = "foo") already create a type with proper
> operator[])?

Yes, it could. The point of keywords<> is to enable positional
parameters as well as named (and also the SFINAE stuff). Anyway, I
checked in some changes to the sandbox that enables list creation with
operator,. Could you try that version out?

-- 
Daniel Wallin