[boost] Re: [function types] Formal Review begins today [REMARK]

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2005-06-10 07:24:30

Tobias Schwinger wrote:
> However, here are two possible recipes of how a Boost.Function could be 
> analyzed with this library:
> 
> 
> 1. AFAIK Boost.Function uses a non-templated parentheses operator 
> therefore you can apply a typeof operator (or Boost.Typeof) on a pointer 
> to its operator() function (you can do this for any functor with a 
> non-template operator()).
> 
> 2.a. The "preferred syntax" is a template parametrized with a (plain) 
> function type to describe its signature. Partial specialization or 
> overloading can be used to get this template argument from an 
> instantiation of 'boost::function'.
> 
> 2.b. The "compatible syntax" is a template parametrized with the 
> sub-types of its signature. There is an (even documented) 
> "corner-case-feature" of 'function_type_signature' that allows you to 
> grab the argument list from a class template instantiation. Because of

^^^^ This feature has been removed ! But it doesn't hurt here because:

- Possibiliy No.1 is the easier and better way to go
- It is unlikely that it would work on compilers where the "compatible syntax" 
of Boost.Function is required.

> this 'boost::functionN' is a valid signature for 'function_type' (given 
> that 'function_type_signature.hpp' is included) together with the tag 
> 'plain_function' to get the same type that a (preferred-syntax) 
> 'boost::function' is instantiated with.