Re: [boost] [futures] boost::futures

From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2007-03-14 15:42:30

On Wednesday 14 March 2007 15:05 pm, Hartmut Kaiser wrote:
> Frank Mori Hess wrote:
> > I have to say I really am not a big fan of needless
> > overloading of the languages operators like logical || and
> > &&.  Especially when you are overloading them with functions
> > that really don't correspond to the original operators.  What
> > if I want to overload || with a function that actually does
> > correspond to logical or, like
> >
> > Future<bool> operator||(const Future<T> &a, const Future<U> &b);
>
> 1. Why do you would do that? Do you have a use case?

Making active functions that take futures as arguments and return futures 
as return values is the primary feature of libpoet.  See 

http://www.comedi.org/projects/libpoet/

So the operator|| above would be used if you wanted to || two results and 
pass the result of the || to another active function without blocking 
waiting for the futures to become ready.  Really it was just an example 
though, I'm not currently planning to implement this (although maybe I 
will someday if I discover it to be useful).

> 2. If you really have to do that, simply do not include the header(s)
> defining the operators.

I don't really have to define an operator||, I could just give the function 
an ordinary name.  My point is, composing futures like in Thorsten 
Schütt's implementation doesn't really have to define an operator|| 
either.  And, if I had to choose which function had a more legitimate 
claim to use operator||, I'd choose my example.

Not including the headers isn't really a solution, since it precludes the 
use of the conflicting functions in the same code.

Pointless overloading isn't a good thing.   What does it buy you here?  A 
pair of parenthesis.

-- 
Frank