Should Loki Functor's return type default?

From: quality_object_software (rubin_at_[hidden])
Date: 2002-01-12 20:44:52

Currently, Loki's Functor is declared as:

     template<typename R, ...

That is, the return type R has no default value.  It seems to me 
that it should default to void.

Rationale:  

1. In general, it makes sense to provide a default value if there's 
a unique, useful value, especially one that's commonly used.  I've 
often used the Command design pattern(tm); most of the time I return 
void. 

2. "Don't return anything" is conceptually simpler than "Return an 
object of type R".

3. Beginners are likely to start with the simplest thing.  They 
shouldn't have to think about the concept of returning a value when 
they're not even using it.  (One could argue that this holds true 
for veterans, too.)

I see no down-side to this proposal.  But perhaps I'm missing 
something.

Bill Rubin