[boost] Re: Formal Review: FOREACH macro

From: Sam Saariste (ss_march2001_at_[hidden])
Date: 2005-04-28 07:56:28

* What is your evaluation of the design?
Very good. It's very easy to use and the support for lvalues access to
container/range elements is very powerful and convenient. Also when using
overloaded operators on the elements, the resulting code is much cleaner
with FOREACH than with an iterator based loop.

* What is your evaluation of the implementation?
Brilliant

* What is your evaluation of the documentation?
Good. The library doesn't need too much documentation really. Maybe some
pitfall section as already has been mentioned would be a useful addition.

* What is your evaluation of the potential usefulness of the library?
Very useful - it lets you express small ad-hoc algorithms in an elegant way
and in the place where you want them.

I have used it for more than 6 months now and have added it to my standard
set of idioms. Once you get into the FOREACH mindset, you don't only want to
use it for std::for_each type jobs but you would also want to use it for
std::transform type ones. In situations where you can use push_back on a
result container, FOREACH serves this purpose as it is. However, I have
encountered situations where this was not possible and where I wanted a
second macro, say FOREACH2, that iterates over 2 ranges simultaneously. I
have had such a need on more than one occasion. One situation was as above
and in other situations I had to combine the elements of two ranges.

I implemented such a FOREACH2 macro myself based on Eric's implementation
and it appeared to be relatively straightforward. For this reason, I would
like to request this as an enhancement to the library. Users of FOREACH
wouldn't be affected by such an additional macro, so I see little reason why
people would object to it. Similarly, I could imagine use for a 3 range
version, where the elements of two ranges are combined and the results get
written into the third range exactly as you can do with std::transform.

* Did you try to use the library?  With what compiler?  Did you have any
problems?
As mentioned above, I have used the library on a regular basis for over 6
months. All my experience is based on using it with VC7.1. I have not had
any problems.

* How much effort did you put into your evaluation? A glance? A quick
reading? In-depth study?
6 month experience with the library from a user perspective. After reading
Eric's article on Artima, I have studied the implementation in quite a bit
of detail so that I could implement an extended version that would iterate
over 2 ranges.

* Are you knowledgeable about the problem domain?
Not more or less than other experienced C++ developers.

* Do you think the library should be accepted as a Boost library?
YES, definitely.

Cheers,
Sam Saariste