Re: [boost] phoenix::bind

Subject: Re: [boost] phoenix::bind
From: Joel de Guzman (joel_at_[hidden])
Date: 2008-09-29 09:56:04

Peter Dimov wrote:
> This is not a review, sorry.
> 
> Is it a goal of phoenix::bind to one day replace lambda::bind and 
> boost::bind, being a superset of both, as well of std::bind?

lambda::bind, yes. std::bind cannot be replaced. boost::bind, too,
IMO cannot be replaced, not in a long time, due to, as you said
below, it works on more compilers.

> I have hoped for boost::lambda::bind to supercede boost::bind. It is a 
> common claim that the only advantage of boost::bind is that it works on 
> more compilers. But this isn't true. It supports constructs which 
> lambda::bind does not; using smart pointers with member functions, 
> member functions of abstract classes, proper const propagation, 
> is_placeholder, _4.._9, and so on. There were other differences (lack of 
> result_type support...) for which I was able to contribute patches to 
> Lambda. But some of the differences are systemic and can only be 
> addressed by a maintainer.

I can definitely make sure that all those are supported.
I supported the lambda tests in phoenix. I can do the same
for boost::bind tests in phoenix.

> Having two components named "bind" has always been a problem for our 
> users. Having three will not help. Ideally, all "bind"s ought to resolve 
> (on a supported compiler circa '08) to the same component.

Sure. Just like what John Maddock did with TR1 tuples targetting
Fuson.Tuples. That can be done.

> When I heard that the next Phoenix (at the time this meant V2) was 
> intended to be the successor to both Phoenix 1 and Lambda, I thought 
> that we were about to finally have a single bind that "just works".

Except on broken compilers though. That's the main reason why
I think boost.bind will be with us for a long time still.

> But - and sorry if this is not the case - I do not get the impression 
> that this is a high priority goal for V2. It'd be nice if I were 
> mistaken; it would be nicer still if phoenix::bind passed all 
> boost::bind tests so that we can just replace boost/bind.hpp with a 
> single using declaration. :-)

It is a priority for Phoenix. I'll make sure that all boost::bind
tests will pass.

Thanks for your comments. All points noted.

Regards,
-- 
Joel de Guzman
http://www.boostpro.com
http://spirit.sf.net