Re: [Boost-users] [Bind] arity of arbitrary object

From: Sohail Somani (s.somani_at_[hidden])
Date: 2007-01-16 19:51:22

-----Original Message-----
From: boost-users-bounces_at_[hidden] on behalf of Peter Dimov
Sent: Tue 1/16/2007 4:17 PM
To: boost-users_at_[hidden]
Subject: Re: [Boost-users] [Bind] arity of arbitrary object
 
Sohail Somani wrote:

> Hi, I've attached up something that seems to kind of maybe work in
> g++. Don't have access to any other compiler at the moment, so I
> can't tell you if it will work or if it is even conforming to
> standard.

No, this doesn't quite work. It says that bind( f, _5 ) has arity 1, but the 
correct answer is 5. Similarly, it says that bind( f, 1, 2 ) has arity 2, 
while the correct answer is 0. You need something like (pseudocode)

arity( _bi::bind_t<R,F,L> ) :- max( arity( e ) ) for each e in L
arity( X ) :- is_placeholder<X>::value

This could be much easier with a bind that uses a fusion tuple as L. :-)

--------------------

Ah, you're right! Could it still be made to work using the same idea? I'm actually not sure what the bind_t type looks like when you do bind(f,_5).

With you on fusion tuple :-)