[boost] Re: once again: boost.bind namespace conflicts and how tosolvethem

From: Stefan Slapeta (stefan_nospam__at_[hidden])
Date: 2004-11-29 17:53:05

Peter Dimov wrote:
> 
> Currently boost/ appears to contain 98 header files. Bringing this down 
> to 97 wouldn't be much of an improvement.
> 

I didn't propose to delete the old one.

> You bring up the legitimate problem of bind's _1 clashing with lambda's 
> _1 (when "using namespace boost::lambda" is in effect), but I totally 
> don't see what this has to do with moving boost::bind to boost::bind::bind.
> 

Symmetry:

boost::lambda::bind, boost::bind::bind (or maybe boost::function::bind 
and also include boost.function library there)

> To answer your specific question, ::_1 selects the Bind placeholder and 
> boost::lambda::_1 selects Lambda's one; consequently, "using ::_1" is an 
> using declaration for Bind's _1, and "using boost::lambda::_1" is the 
> using declaration for its Lambda counterpart. I only tested them on VC 
> 7.1, though; maybe your compiler doesn't accept them?
> 

This might be a different discussion but I simply don't understand what 
are the rules for putting boost.bind and boost.function in the 'global' 
boost namespace and many other libraries not. Historical reasons? A 
matter of interface size?

[...]
> 
> Probably not. You'll use "using namespace boost::placeholders" instead, 
> when bind is modified to conform a bit more closely to TR1. The problem 
> is that this breaks existing code. Of course when you have two using 
> directives, one for Bind and one for Lambda,  _1 will once again become 
> ambiguous.

There will be other headers for the TR1 implementations, so breaking 
existing code is not so much my problem.

Stefan