There are a number of reasons why you better choose a commercial Prolog
system, or another academic product:
SWI-Prolog is not supported
Although I usually fix bugs shortly after a bug report arrives, I cannot
promise anything. Now that the sources are provided, you can always
dig into them yourself.
Memory requirements and performance are your first concerns
A number of commercial compilers are more keen on memory and performance
than SWI-Prolog. I do not wish to offer some of the nice features of
the system, nor its portability to compete on raw performance.
You need features not offered by SWI-Prolog
In this case you may wish to give me suggestions for extensions. If
you have great plans, please contact me (you might have to implement
them yourself however).
On the other hand, SWI-Prolog offers some nice facilities:
Nice environment
This includes `Do What I Mean', automatic completion of atom names,
history mechanism and a tracer that operates on single key-strokes.
Interfaces to standard Unix editors are provided, as well as a facility
to maintain programs (see make/0).
Very fast compiler
The compiler handles about 5K bytes per second per MIPS (i.e. 35K bytes
per second on SUN-4/110).
Transparent compiled code
SWI-Prolog compiled code can be treated just as interpreted code: you
can list it, trace it, assert from or retract to it, etc. This implies
you do not have to decide beforehand whether a module should be loaded
for debugging or not. Also, performance is much better than the
performance of most interpreters.
Profiling
SWI-Prolog offers tools for performance analysis, which can be very
useful to optimise programs. Unless you are very familiar with Prolog
and Prolog performance considerations this might be more helpful than a
better compiler without these facilities.
Flexibility
SWI-Prolog allows for easy and flexible integration with C, both
Prolog calling C functions as C calling Prolog predicates. SWI-Prolog
is provided in source form, which implies SWI-Prolog can be linked in
with another package. Command line options and predicates to obtain
information from the system and feedback into the system are provided.
Integration with PCE
SWI-Prolog offers a tight integration to the Object Oriented Package
for User Interface Development, called PCE ([#!P1098:C1.6!#]). PCE
is now also available for X-windows.