This document discusses the history and evolution of programming languages from early examples like Fortran and COBOL in the 1950s-60s to more modern languages like JavaScript, Python, and SQL. It covers important developments like object-oriented programming, functional programming, logic programming, and web technologies like CGI and Ajax. The document seeks to illustrate how programming languages have developed over time to model different kinds of problems and paradigms.

1. Programming
languages
www.tudorgirba.com

2. computation
information information
computer

3. A language is a set of sequences of symbols that
we interpret to attribute meaning.

4. ambiguous
All elements of an array a of length N are either zero or one
(1) ∀i: 0≤i<N: ( ai=0 ∨ ai=1 )
(2) (∀i: 0≤i<N: ai=0) ∨ (∀i: 0≤i<N: ai=1)
Example

5. A programming language is a a language for
communicating software designs.

10. programming = modeling

11. # Compute factorials
def fact(n)
if n == 0
1
else
n * fact(n-1)
end
end
puts fact(ARGV[0].to_i)

12. # Compute factorials
def fact(n)
if n == 0
1
else
n * fact(n-1)
end
end
statements puts fact(ARGV[0].to_i)

13. # Compute factorials
def fact(n)
if n == 0
1
else
n * fact(n-1) expression
end
end
statements puts fact(ARGV[0].to_i)

14. # Compute factorials variables
def fact(n)
if n == 0
1
else
n * fact(n-1) expression
end
end
statements puts fact(ARGV[0].to_i)

15. # Compute factorials variables
def fact(n)
if n == 0
literals
1
else
n * fact(n-1) expression
end
end
statements puts fact(ARGV[0].to_i)

16. # Compute factorials variables
def fact(n)
if n == 0
literals
1
else
control n * fact(n-1) expression
constructs end
end
statements puts fact(ARGV[0].to_i)

17. functions
# Compute factorials variables
def fact(n)
if n == 0
literals
1
else
control n * fact(n-1) expression
constructs end
end
statements puts fact(ARGV[0].to_i)

18. comments functions
# Compute factorials variables
def fact(n)
if n == 0
literals
1
else
control n * fact(n-1) expression
constructs end
end
statements puts fact(ARGV[0].to_i)

19. in g, 1937
Alan Tur

20. Smalltalk = = Java

22. programming = modeling

24. Imperative
data + algorithms

25. Imperative
data + algorithms
Object-oriented
objects + messages

26. Imperative Functional
data + algorithms stateless + pure functions
Object-oriented
objects + messages

27. Imperative Functional
data + algorithms stateless + pure functions
Object-oriented Logic
objects + messages facts + rules

28. Jacquard loom
1801

29. Babbage’s
Analytical
Engine
1837

30. Church’s
Lambda Calculus
1932
(λ x. (λ y. x)) a b
(λ y. a) b
a

31. Touring Machine
1936

32. Harvard
Mark I
1944

33. Subroutine
1949

34. Assembly code
1950s

35. Fortran
1955
C AREA OF A TRIANGLE - HERON'S FORMULA
C INPUT - CARD READER UNIT 5, INTEGER INPUT
C OUTPUT - LINE PRINTER UNIT 6, REAL OUTPUT
C INPUT ERROR DISPAY ERROR OUTPUT CODE 1 IN JOB CONTROL LISTING
INTEGER A,B,C
READ(5,501) A,B,C
501 FORMAT(3I5)
IF(A.EQ.0 .OR. B.EQ.0 .OR. C.EQ.0) STOP 1
S = (A + B + C) / 2.0
AREA = SQRT( S * (S - A) * (S - B) * (S - C))
WRITE(6,601) A,B,C,AREA
601 FORMAT(4H A= ,I5,5H B= ,I5,5H C= ,I5,8H AREA= ,F10.2,12HSQUARE UNITS)
STOP
END

36. ALGOL
1958
begin
...
end
<statement> ::= <unconditional statement>
| <conditional statement>
| <for statement>
...
f()
...
f()

37. Lisp
1958
(defun factorial (n)
(if (= n 1)
1
(* n (factorial (- n 1)))))
Garbage collection
Programs = Data

38. COBOL
1959
ADD YEARS TO AGE.
MULTIPLY PRICE BY QUANTITY GIVING COST.
SUBTRACT DISCOUNT FROM COST GIVING FINAL-COST.
Modules

39. Basic
1964
10 INPUT "What is your name: ", U$
20 PRINT "Hello "; U$
30 INPUT "How many stars do you want: ", N
40 S$ = ""
50 FOR I = 1 TO N
60 S$ = S$ + "*"
70 NEXT I
80 PRINT S$
90 INPUT "Do you want more stars? ", A$
100 IF LEN(A$) = 0 THEN GOTO 90
110 A$ = LEFT$(A$, 1)
120 IF A$ = "Y" OR A$ = "y" THEN GOTO 30
130 PRINT "Goodbye "; U$
140 END

40. JCL
1964
//IS198CPY JOB (IS198T30500),'COPY JOB',CLASS=L,MSGCLASS=X
//COPY01 EXEC PGM=IEBGENER
//SYSPRINT DD SYSOUT=*
//SYSUT1 DD DSN=OLDFILE,DISP=SHR
//SYSUT2 DD DSN=NEWFILE,
// DISP=(NEW,CATLG,DELETE),
// SPACE=(CYL,(40,5),RLSE),
// DCB=(LRECL=115,BLKSIZE=1150)
//SYSIN DD DUMMY

41. Semaphores
1965
P1 — acquire resource X
… critical section
V1 — release resource X
P2 — acquire resource X
… critical section
V2 — release resource X

42. Planner Prolog
1969 1972
man(socrates).
mortal(X) :- man(X).

43. Planner Prolog
1969 1972
man(socrates).
mortal(X) :- man(X).
?- mortal(socrates).
Yes

44. Planner Prolog
1969 1972
man(socrates).
mortal(X) :- man(X).
?- mortal(socrates).
Yes
?- mortal(elvis).
No

45. Pascal
1970
function gcd (a, b: integer) : result real;
var x : integer;
begin
if b= 0 then gcd := a
else
begin
x := a;
while (x >= b) do
begin
x := x - b
end;
gcd := gcd(b,x)
end
end

46. C
1972
#include <stdio.h>
//echo the command line arguments
int main (int argc, char* argv[]) {
int i;
for (i=1; i<argc; i++) {
printf("%s ", argv[i]);
}
printf("n");
return 0;
}

47. Smalltalk
1972
Integer»factorial
self = 0 ifTrue: [^ 1].
self > 0 ifTrue: [^ self * (self - 1) factorial].
self error: 'Not valid for negative integers'
5 factorial -> 120
Everything is an Object
Everything happens by sending messages

48. Monitors
1974
public class Account {
protected int assets = 0;
...
public synchronized void withdraw(int amount) {
while (amount > assets) {
try {
wait();
} catch(InterruptedException e) { }
}
assets -= amount;
}
...
}

49. Bourne shell
1977
cat Notes.txt
| tr -c '[:alpha:]' '012'
| sed '/^$/d’
| sort
| uniq –c
| sort –rn
| head -5

50. SQL
1978
SELECT *
FROM Book
WHERE price > 100.00
ORDER BY title;

51. Perl CGI
1978 1993
#!/usr/bin/perl -w
print "Content-type: text/htmlnn";
print <<'eof'
<html><head><title>Directory contents</title></head>
<body>
<h1>Directory contents</h1><ul>
eof
;
@files = <*>;
foreach $file (@files) {
print '<li><a href="' . $file . '">' . $file . "</li>n";
}
print "</ul></body></html>n";
__END__

52. JavaScript Ajax
1995 2005

54. programming = modeling

55. Tudor Gîrba
www.tudorgirba.com
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