1. Functional Programming Languages Logic Programming Languages
Case Study
Functional Programming Languages
Logic Programming Languages

2. Functional Languages There are many functional languages. Scheme
Haskell F# ML
Lisp
Others

3. Scheme
Scheme was developed at the MIT AI Lab by Guy L. Steele and Gerald Jay Sussman who introduced it to the academic world via a series of memos
Defining Variable:
(define a 10)
(+ a 2)

4. Scheme Printing : To put new line: Arithmetic Expression:
(display "Hello world")
To put new line:
(newline)
Arithmetic Expression:
( )

5. Scheme
Assignment Statement:
(define b 10)
(* b 2)
(set! b 30)

6. Scheme (define (greet) (display "Hello, world!") (newline) )
(let ((x 1) (y 2))
(+ x y))

7. Logic Language
Prolog
Developed at Univ. of Aix-Marseille and Edinburgh in early to mid 1970s
Goal: natural language processing and theorem proving.
Used in Japan’s Fifth Generation Computing Project in 1981

8. Prolog Prolog Syntax Variables are uppercase
constants, predicates are lowercase
List syntax:
[1, 2, 3]
[head | tail]
Program consists of
facts, rules, and goals

9. Prolog Facts female(shelley). male(bill). female(mary). male(jake).
father(bill, jake).
father(bill, shelley).
mother(mary, jake).
mother(mary, shelley).

10. Prolog Rules parent(X, Y) :- mother(X, Y).
parent(X, Y) :- father(X, Y).
grandparent(X, Z) :-
parent(X, Y), parent(Y, Z).
sibling(X, Y) :-
mother(M, X), mother(M, Y),
father(F, X), father(F, Y).
ancestor(X, X).
ancestor(X, Y) :-
parent(X, Z), ancestor(Z, Y)

11. Prolog Queries ?- father(bill, jake). yes ?- father(X, jake). X = bill
?- father(bill, X).
X = jake
; X = shelley