Lambda library - comparison with FACT and other solutions?

From: Asger Alstrup Nielsen (alstrup_at_[hidden])
Date: 2002-03-18 07:35:01

Hi,

While the Boost Lambda Library under current review is very impressive,
I think it would be relevant to discuss the relation with other
solutions to the same problem.

In particular, I'm interested in the relation to FACT!:

http://www.kfa-juelich.de/zam/FACT/start/index.html

FACT! solves many of the same problems, but uses a different approach.
It is not as well-documented as BLL, and I think there are licensing
problems that would prevent Boost inclusion, but I believe it is
relevant with a technical discussion about the different approaches.

Without being an expert on either BLL or FACT, I think the most
prominent difference is how to construct lambda expressions.

As I understand it, in BLL, a lambda expression is implicitly build when
you refer to the magical variables _1, _2, and so on in expressions like
"_1 + _2". In FACT, you construct a lambda expressions explicitly like
this "lambda(x, y, x + y)".

There are pros and cons for each approach, and I'm interested in a
discussion about these, and other differences.

I've cc'ed the author of FACT, and hope he will participate in the
discussion.

Thank you,

Asger Alstrup Nielsen