Re: [boost] [Graph][Property map] Why aren't property maps function objects?

From: garcia (garcia_at_[hidden])
Date: 2003-12-06 11:32:18

Douglas Gregor wrote:

>Today I (again) ran into an instance where I had a property map but really 
>wanted a function object. The code I wanted to write was:
>
>  std::vector<vertex_descriptor> reversed_order(num_vertices(rdg));
>  depth_first_search(rdg,
>                         boost::visitor(
>                           make_dfsnum_visitor(reversed_order.begin())));
>  return transform(reverse_order.rbegin(), reverse_order.rend(),
>                        out, get(symbol_tag(), rdg));
>
>get(symbol_tag(), rdg) returns a property map now, so this code is ill-formed. 
>At the moment I either have to wrap the property map (yuck) or just fall back 
>to a hand-coded loop (also yuck).
>
>Would anyone object if I made property maps into function objects? Any 
>downsides?
>
>  
>
Are you suggesting changing the interface specified by the concepts in 
the property map library, specifically, the LValuePropertyMap?

ron