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Subject: Re: [boost] Formal Review: Boost.RangeEx
From: David Abrahams (dave_at_[hidden])
Date: 2009-03-02 15:13:45

on Mon Mar 02 2009, Arno Schödl <> wrote:

> Dave,
>> r | transform(f) | filter(g) | whatever(h)
>> = whatever(filter(transform(r, f), g, h))
> why this way around? Why not
> whatever( h, filter(g, transform(f, r) )
> which I don't find much worse than the operator| notation,

Better than what I cited, but still inferior to operator|

> and it works consistently with anything that expects functions,
> boost::bind, boost::function, whatever other people have already
> implemented that invokes operator().

That's indeed a real advantage to function call notation. On the other
hand, we have libraries like lambda and phoenix that allow us to work
with the operators in a similar way.

> I agree with Rogier that I don't see why ranges are so different from
> doubles, say, that would warrant introducing a new syntax.
> And wouldn't concepts in C++0x allow augmenting Ranges with things that can be invoked
> method-style, like
> r.transform(f).filter(g).whatever(h)

You could do that today, but it's got the same coupling problem as named
parameters in Boost.Graph and is solved by Boost.Parameter. Is there
something in C++0x that causes decoupling?

Dave Abrahams
BoostPro Computing

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