Re: [boost] Simple yet interesting object factory

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2007-09-02 07:42:36

Marco Costalba wrote:
> Indeed in the above link I fail to see the mapping framework between
> class identifiers and actual creators/factories for that class, or put
> in other words I don't see the dispatcher.

It's not there, because it's just trivial to implement with what we 
already have in Boost and the standard library (as shown in the previous 
post) e.g. using 'std::map' for the mapping and 'boost::function' for 
the type erasure. See

     http://www.sgi.com/tech/stl/Map.html
     http://www.boost.org/doc/html/function.html

> 
>> A similar approach could be done with
>> http://dispatcher.sourceforge.net/ -- only this time it's not required
>> that the function registered is a "factory". It could very well be any
>> function registered.
>>

Same with the code I posted.

The factories are just adapters to make a construction expressions 
first-class function objects which are then type-erased and stored in 
'boost::function's...

So it seems a

     'dispatcher<Key,Sig>'

is pretty much like a

     'std::map<Key,boost::function<Sig> >'

;-).

Regards,
Tobias