Re: [boost] Re: Formal Review: FOREACH macro

From: Dave Harris (brangdon_at_[hidden])
Date: 2005-05-02 19:24:35

In-Reply-To: <d55q7o$4g5$1_at_[hidden]>
SeeWebsiteForEmail_at_[hidden] (Andrei Alexandrescu (See Website 
For Email)) wrote (abridged):
> > Comparing:
> > 
> >     BOOST_FOREACH( int i, vec )
> >         cout << i;
> > 
> > with:
> > 
> >     for (iterator i = vec.begin(); i != vec.end(); ++i)
> >         cout << *i;
> > 
> > the macro just doesn't seem worth it.
> 
> In fairness, it's
> 
> for (vector<ArbitrarilyComplexType>::iterator i = vec.begin(); i != 
> vec.end(); ++i)
>      cout << *i;

No, I meant what I wrote. I usually have a suitable iterator typedef in 
scope. In the worst case it is more like:

   typedef vector<ArbitrarilyComplexType> MyVec;
   for (MyVec::iterator i = vec.begin(); i != vec.end(); ++i)
       cout << *i;

where "MyVec" is some meaningful name (and is probably itself worth 
putting at some larger scope - after all, where did the vec come from?). 
And I see adding a typedef as clearer, transparent even, compared to the 
BOOST_FOREACH macro.

> I think the part of the discussion that focuses on arguments for or 
> against macros is misplaced.

Agreed. As I said earlier, I am not absolutely against macros; I won't 
automatically vote against any proposal that uses them. I am also 
objecting to BOOST_FOREACH because it is taking something simple and 
making it complicated.

-- Dave Harris, Nottingham, UK.