After discovering Borland's Turbo Pascal
in the late eighties and programming in that for some time, I switched to
Borland's Turbo Prolog - which was rather like TurboPascal - and
programmed quite a lot in that, and also in its successor PDC Prolog.
In fact Turbo Prolog was Borland's implementation of what
later became PDC Prolog. Both incorporated the same idea: To translate
Prolog-code into C, and compile that. This worked quite well, and I wrote
rather a lot of code in Turbo Prolog, including a hypertext-editor, for
which PDC produced a special compiler around 1990 that I bought.
At the time this hypertext-editor - called Edith
- was at the forefront of technology: It had indexes, long filenames, the
ability to start programs and return etc. and I used it as my personal
text-editor for several years, simply because it was the best for my purposes,
and I could do many things with it I couldn't do with any other editor running
All this was before the days of the internet and before
Windows95 and later. I tried several other Prologs such as LPA Prolog
but at the time - 1990-1995 - PDC Prolog met my programming needs best.
Then the internet and html were invented, and
there rapidly appeared WYSIWYG-editors for html to which I switched, since
this was much more pleasant to the eye than DOS-programs, and also more useful
PDC Prolog was for DOS, but got revamped for Windows as
VIP Prolog or Visual Prolog. I bought an early release of that, but
didn't much like it, and switched for programming for Windows to Delphi,
which was Borland's followup of Pascal.
PDC Prolog at this time of writing - May 2007 - still exists
and still develops Visual Prolog, but I haven't looked at it after Visual
Prolog 6.0, in part because I didn't like it much, and in part because it is
neither open source nor free, and I am much in favour of programming with free
Also, it seems to me that these days the sort of
search-engine programming at which Prolog excels (backtracking) can be written just a well in
another high-level language.