Thanks for your input. I'd like to concentrate on this:
I think the discussion is about `free'. As you can learn from the FSF
website, free isn't about free as in free beer, but in free as in
freedom of speech. That is the case here as well. I'm more inclined to
use `Open'. Not in the way you us it, although that form of openness is
important to reach my `Open': community carried software. If you want to
do commercial development with a free Prolog, you should become member
of its community and guide it in the direction you want, either by
investing time in development, testing, documenting, etc. or by
investing money to get someone else (sometimes the main developers,
sometimes another expert) do the work. Using that principle it works for
both sides. The developers get financial resources and code from the
community, the users gets direct access to developers and the rest of
the community and profits from the testing and extensions from other
parts of the community.
Done properly, this is highly effective for everybody because it greatly
reduces overhead costs. Just think or marketing, legal costs, trying to
establish and protect license schemas, financial and organizational
hassle buying and selling software, etc.
Note that it works for small and big communities and even comparable to
commercial software. Specialized commercial software is very expensive,
while in small open communities each member needs to invest majorly. Big
mainstream commercial software is cheap and in big mainstream open
projects you don't have to do much.
I think Markus is doing a great job establishing a clp(fd) library with
some nice features. I'm sure he is interested in enhancing the design
and make it easy to extend.
Some things are almost inherently associated with community software.
Not that many developers like documenting and where documenting a single
piece of the cake is still doable, keeping the dependencies in the
overall documentation up to date is asking too much. Only big
communities can fix the documentation problem by regularly publishing
nice integrated documentation as a book. Small communities have to work
with nice, largely automated, tools to get some minimal documentation.
Cheers --- Jan