1. PROLOG

2. PROLOG
a general-purpose logic programming language associated with artificial intelligence and computational linguistics
was first conceived by a group around Alain Colmerauer in Marseille, France, in the early 1970s
has been used for theorem proving, expert systems, term rewriting, type inference, and automated planning, natural language processing

3. INSTALLATION For MAC Go to brew.sh and download homebrew
Then go to your terminal and type brew install gun-prolog
Then go to directory that has prolog files or prolog database
Then type in gprolog

4. INSTALLATION For Windows
Go to cygwin.com/install.html and click on install cygwin
Then click on setup-x86 64.exe
Now, we have to install Prolog and so go to and click on Windows intel 64 bits auto-install setup link
And prolog console is ready

5. FACTS AND RULES A prolog program is a collection of facts and rules
Some examples of facts:

6. FACTS AND RULES
A rule is more complex than a fact, it relates various facts
An example of a rule relating the previous facts:
This rule states that a Thing is expensive (has the property expensive) if the Thing is a car (has the car property) and the Thing is red (has the red property)
Notice that :- means if and , means and

7. FACTS AND RULES Collectively, facts and rules are known as clauses
A collection of clauses constitute a program
The above clauses would be written in a file and the file loaded into the prolog interpreter

8. FACTS AND RULES
Within the prolog interpreter, type car(dino). at the ?- prompt
The ?- prompt is also known as the query prompt

9. FACTS AND RULES
The interpreter reads the query and extracts the functor (property) car and the object dino
Then It goes through each line of the program, always starting from the first line to find a fact that has the same functor as the query, i.e. car
Prolog replies No. Because it cannot find a match in any of the rows of the program

10. VARIABLES
X is a variable and stands for any object that has the car property
Variables are always written with an upper case initial letter
Objects or constants are written with a lower case initial letter
Thing is a variable because of the initial upper case T
In response to the above query, prolog replies

11. VARIABLES A variable without a value is called unbound
A variable with a value is called bound
In db.pl In prolog console

12. VARIABLES
In db.pl: In prolog console:

13. VARIABLES
In db.pl: In prolog console:

14. SYNTAX The Prolog data structure is the term
Terms are nested structures defined recursively as
Constant: Integer, Real, Atom
Variable: named (initial letter upper case), (anonymous)
Structure: functor with parameters or components, each of which may be a term likes (fred, whisky(malt, 12), X) where likes and whisky are functors of arity 3 and 2 respectively
An atom is a functor of arity 0
Prolog has built-in binary operators, so that we may write 3+4*5
Prolog has no global variables

15. PROLOG CONSOLE
Facts and rules are stored in a file called either the database or knowledge base: i.e. db.pl
?- [db]. (to load your knowledge base inside prolog console)
Ex: ?- ['C:/Users/username/Desktop/db.pl'].
?- consult(‘db.pl’). (to load your knowledge base inside prolog console)
?- halt. (to exit out of the G prolog)
$ gprolog (to return to your terminal)
?- listing. (it’s going to show a whole bunch of information about the contents of the database)

16. PROLOG

17. PROLOG ~w  If you want to put in a variable here
~s  If you want to transpose a string inside of here

18. PROLOG

19. CASE STATEMENTS
In db.pl: In prolog console:

20. PROLOG

21. PROLOG

22. COMPARING VALUES
In prolog console:
\+ means not equal

23. DEBUGGING
Trace is used debugging inside of prolog

24. DEBUGGING
Notrace is used to switch off the debugger.

25. PROLOG

26. PROLOG Prolog has built-in binary operators =:=  checks equality
=\=  checks inequality

27. INPUT/OUTPUT Reading input from user nl means new line
read(X) and get(X) is used for this

28. FILE OPERATIONS

29. RECURSION

30. LOOP

31. NAME FUNCTION
name take a string and convert it into a series of ASCII characters
name also converts ASCII characters into a string