Re: programming guidelines, prefer free functions

From: William Kempf (sirwillard_at_[hidden])
Date: 2000-08-17 12:23:05

--- In boost_at_[hidden], jsiek_at_l... wrote:
> 
> It seems to me your argument is mostly about how std::string should
> have been defined, which is a side issue. To argue directly against 
my
> point you need to list reasons for using member functions instead of
> free functions.

Polymorphism.  Access to internal state (and most or all of the state 
should be internal).  If you've coded a member function that only 
calls other public member functions you've probably found something 
that shouldn't have been a member function.

The latest topic to have brought this issue up was the wait function 
for our CV.  To make it free standing will require either exposing 
state information publicly that should not be exposed, or (ab)using 
friend functions.  Making a wait method free standing by using friend 
doesn't resolve your original issue since other interfaces won't have 
the luxury of being friends.  If all they do is wrap the other free 
standing wait function then there was no benefit gained from it being 
free standing in the first place, since you could have just as easily 
wrapped the member function with the same free standing wrapper.

William Kempf