Right now Prolog is available on the elk machines, so one must first do an ssh to elk0n, n=1,6. Here is a sample prolog source file, stored using the filename hanoi.pl and a sample session showing the use of this file (boldface is user input):

% ssh wagner@elk01.cs.utsa.edu password: (give password here) elk01% apropos prolog plld (1) - Create emb. executable plrc (1) - SWI-Prolog res. arch. prolog (1)- SWI-Prolog 5.6.59 swipl (1) - SWI-Prolog 5.6.59 xpce (1) - Prolog with GUI elk01:~> cat hanoi.pl % move all discs onto the center pole % discs start piled in order at left hanoi(N) :- move(N, left, center, right). move(0, _, _, _) :- !. move(N, A, B, C) :- M is N-1, move(M, A, C, B), inform(N, A, B), move(M, C, B, A). inform(I, X, Y) :- write('move disc '), write(I), write(' from '), write(X), write(' to '), write(Y), nl.

elk01% prolog Welcome to SWI-Prolog ... ... blah, blah ... ?- consult(hanoi). % hanoi compiled 0.00 sec, 1,640 bytes true. ?- hanoi(1). move disc 1 from left to center true. ?- hanoi(2). move disc 1 from left to right move disc 2 from left to center move disc 1 from right to center true. ?- hanoi(3). move disc 1 from left to center move disc 2 from left to right move disc 1 from center to right move disc 3 from left to center move disc 1 from right to left move disc 2 from right to center move disc 1 from left to center true. ?- halt.

spr03u(cs2213, '001', 1900-mw, maltrud). spr03u(cs2213, '002', 0930-tr, maltrud). spr03u(cs2413, '001', 1000-mwf, maynard). spr03u(cs2513, '001', 1200-mwf, key). spr03u(cs2733, '001', 1300-mwf, wagner). spr03u(cs3233, '001', 1230-tr, tian). spr03u(cs3343, '001', 1530-tr, kwek). spr03u(cs3723, '001', 1200-mwf, wagner). spr03u(cs3733, '001', 1230-tr, srobbins). spr03u(cs3743, '001', 1900-tr, staff). spr03u(cs3773, '001', 1730-tr, lo). spr03u(cs4313, '001', 1400-mw, bylander). spr03u(cs4363, '001', 1000-mwf, wagner). spr03u(cs4383, '001', 1300-mwf, maynard). spr03u(cs4753, '001', 1730-mw, yum). spr03u(cs4913, '000', arranged, staff). spr03u(cs4953, '001', 0930-tr, srobbins). spr03u(cs4993, '000', arranged, staff). semesteru(X, Y, Z, W) :- spr03u(X, Y, Z, W). year('2003'). season('Spring').

These facts need to be combined with many other facts and rules to produce a reasonable listing. Some of the facts are names of courses, full names of instructors, better representation for times, and others. These additional facts and rules do not change (much) from semester to semester, so they are more-or-less universal.

• Database of upper-division CS courses. This is an initial very simple version to illustrate how the system works.
  • The Prolog file for courses for Spring 2003 (4.3 kbytes): spring03.pl.
  • Interactive session illustrating the program (3.5 kbytes): spring03.html.
• Database of upper-division CS courses. This is also a simplified version to help illustrate the principles.
  • The courses for Spring 2003 (0.8 kbytes): spring03.pl.
  • The file of fixed facts and rules that are independent of the semester (9.7 kbytes): general.pl.
  • The result of "running" this program, to produce a .html file (7.8 kbytes): spring03.html.
• The complete database for Spring 2003 courses. This is the full database of all courses. It is essentially the same as the previous example, but there are many additional details. This expanded version is about 5 times as large as the previous one.
  • Spring 2003 courses in Prolog (4.6 kbytes): spr03.pl.
  • The large file that handles all semesters (37.6 kbytes): general3.pl.
  • Resulting .html (32.7 kbytes): spr04.html.