prolog
Here I have some notes about prolog. I am using GNU Prolog. More information can be found at GNU Prolog manual and GNU Prolog tutorial.
First steps
Prolog is a symbolic language in which we declare facts and rules to then ask questions that will be answered based on these data.
Installing gnu prolog
Download and uncompress gprolog-1.4.5. After going to gprolog folder:
$ ./configure
$ make
$ sudo make install
Running a simple application on gnu prolog
Starting in a very simple way, let us prepare a set of facts. In gnu prolog, it must be written in a file. Let us considerer the file zoo.pl with the following content:
animal(turtle).
animal(tiger).
animal(giraffe).
Running gnu prolog on the folder we have the file zoo.pl:
$ gprolog
GNU Prolog 1.4.5 (64 bits) Compiled Apr 12 2020, 18:50:29 with gcc
By Daniel Diaz
Copyright (C) 1999-2020 Daniel Diaz
|?-
Importing zoo.pl and making first assertion:
|?- consult(zoo).
|?- animal(X).
The answer will be X = turtle ?, pressing ; it shows X = tiger ?, pressing ; again it shows the last true value for X: X = giraffe. The command consult(file) and be replaced by [file].
In fact, currently, it is all we have in the database as we can check using listing command:
|?- listing.
% file: /media/data/zoo.pl
animal(turtle).
animal(tiger).
animal(giraffe).
yes
|?-
To exit from gnu prolog:
|?- Ctrl+C, then e (to exit).
Adding new facts
|?- assertz(bigger(giraffe,lion)).
|?- assertz(bigger(lion,turtle)).
Appending elements to a list
To be continued...
I am following the material from http://www.cs.trincoll.edu/~ram/cpsc352/notes/ which is very practical.
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