This prolog package (which has been hacked about a bit by me to get it working
with comments & blank lines in input files) was originally developed by
the ANNA tools group (ANNotation language for Ada - high powered assertions).
In it's current form it can accept a sequence of prolog facts, which you
can then query.
For example the following series of facts...
subject (cs108).
year (cs108, 1).
semester (cs108, 1).
subject (cs109).
year (cs109, 1).
semester (cs109, 2).
subject (cs208).
year (cs208, 2).
semester (cs208, 1).
subject (cs209).
year (cs209, 2).
semester (cs209, 2).
lend themselves to questions such as...
What subjects were run in 1st year?
What subjects were run in 2nd semester?
These would be handled by entering a query with an 'unbound'
variable in the place of the missing value. An unbound variable
(not bound to any particular answer) starts with a capital
letter.
E.g.
What subjects were run in 1st year?
Query year (X, 1).
Answer cs108
cs109
What subjects were run in 2nd semester?
Query semester (X, 2).
Answer cs109
cs209
What semester was cs209 run in?
Query semester (cs209, X).
Answer 2
What subjects are there?
Query subject (X).
Answer cs108
cs109
cs208
cs209
More complex queries can be constructed by creating rules, which
are then queried
What subjects that start in 1st semester are run in 2nd year?
Rule solution (X) :- semester (X,1), year (X,2).
Query solution (X).
Answer cs208
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-- Using the program --
-------------------------
The program
demo.adb
gives an example of how to use this package.
As well the file
demo.pro
course.pro
contain example Prolog programs
Note that the file
intlibc.pro
is required to be available, and contains various rules that the
packages use to solve queries.
Prolog is a wonderfully powerful language, and this interpreter brings
*some* of that power to you.
COPYRIGHT NOTICE
Read the file COPYING for details of the current copyright status
of this code.