RE: [boost] function.hpp: some ideas

From: Jesse Jones (jesjones_at_[hidden])
Date: 2001-05-07 05:17:59

At 9:52 AM +0200 5/7/01, Geurt Vos wrote:
>  > >
>>  > Hmm, I would say if I can assign a function pointer, it is
>>  > only natural that I can also assign 0. Additionally, since
>>  > 'if (f)', or  better 'if (f !=/== 0)' is possible, it again
>>  > makes 'f = 0' an obvious possibility.
>>
>>  I completely disagree with this :)
>>  The conversion to bool (const void*, const undeleteable*, whatever)
>should
>>  be though of as: 'if f evaluates true, then f has some target it will
>execute
>>  if you invoke f's function call operator' not 'f can be implicitly
>converted
>>  to its function pointer'. boost::function deals with function objects, not
>>  function pointers; function objects are copy constructible and invocable,
>and
>>  function pointers are a refinement of function objects that are also
>>  assignable and equality comparable. We need to look at the core concept
>that
>>  boost::function handles - the function object - and not inject syntax for
>it
>>  based on the properties of specific refinements of that concept (Jesse -
>same
>  > argument goes for operator==).

The problem with this is that if boost::function doesn't have 
operator== users are hosed. Their only recourse is to code some sort 
of work around or use a different callback class with a huge amount 
of overlap with boost::function.

   -- Jesse