Re: [boost] Iterator Adaptor not using traits as template args

From: Jeremy Siek (jsiek_at_[hidden])
Date: 2001-02-27 21:37:51

Another variation:

  boost::iterator_adaptor<int*, reverse_iterator_policies,
    iterator_traits_builder
      ::Reference<int>::Pointer<int*>::Distance<std::ptrdiff_t>
      ::Value<int>::Category<std::input_iterator_tag>
  >

The above is closer to Aleksey's initial suggestion, except that the Base
type does not go into the iterator_traits_builder. Instead types not
specified in the iterator_traits_builder are assigned a default_argument
type, which the iterator_adaptor notices and swaps for the real default
type.

With the above, the iterator_adaptor just takes a Traits class as the
third argument, and people can optionally use the builder.

On Tue, 27 Feb 2001, David Abrahams wrote:

abraha> It's all very well and good to emulate keyword arguments,
abraha> but shouldn't they be optional? After all, the type
abraha> described below is nearly just:
abraha> 
abraha> boost::iterator_adaptor<const int*, boost::reverse_iterator_policies>
abraha> 
abraha> I realize the type below is more explicit, but it's also a
abraha> /lot/ more complex.
abraha> 

----------------------------------------------------------------------
 Jeremy Siek                        www: http://www.lsc.nd.edu/~jsiek/
 Ph.D. Candidate                  email: jsiek_at_[hidden]
 Univ. of Notre Dame         work phone: [phone]
----------------------------------------------------------------------