SWI-Prolog is available as prepackaged binaries for Mac OS X 10.3+, but
not for 10.2. If you try and install the 10.3 binary package, you
will get errors (at least, I did). The answer is to compile from
source. You are probably compile-savvy if you are looking to
install a Prolog interpreter, but if not, it's a fairly painless
./configure, make, make install process.
1. However, the docs warn that you'll want readline and a number of
other libraries installed. There are some binary packages on the
SWI-Prolog site. If you want to use those, and you don't have any
other versions of the libraries, so be it — but I would recommend
using Fink instead, so that you can install the most up to date
versions.
2. Especially if using Fink, be sure to alert the ./configure script to
the locations by including LDFLAGS=”-I /sw/include” and CFLAGS=”-L
/sw/lib” (or wherever).
For me, all it took was pointing the configure script to the /sw tree and it compiled with no further questions.