Named template parameters [was: Most needed/desired features in C++]

From: Beman Dawes (bdawes_at_[hidden])
Date: 2002-02-18 12:24:21

At 11:12 AM 2/18/2002, Jeremy Siek wrote:

 >I'd like to see some form of named/keyword parameters for template
 >parameters and perhaps also function parameters.

Agreed.

 > The lack of this has made
 >parts of the boost graph library very difficult to design and implement.
 >
 >As posted earlier, there's a difficulty in trying to shoehorn named
 >parameters into the current framework, because parameters names currently
 >don't mean anything, only position does. Take for example:
 >
 >template <typename A = char, typename B = int> class foo;
 >...
 >template <typename B = char, typename A = int> class foo;
 >
 >foo<B=int> // what does this mean?

Can't you just say "first seen?" as the answer to the question?

An implementation might also (as QOI) warn if additional declarations 
rename or reorder the parameters.

--Beman