22_ideals

Abstract

This is a very brief and very selective history of software

Overview

Ideals
Aims, heroes, techniques
Languages and language designers
Early languages to C++
(There is so

History and ideas

One opinion
“History is bunk”
Another opinion
“He who does not know

What is a programming language?

A tool for instructing machines
A notation for

Greek heroes

Every culture and profession must have ideals and heroes
Physics: Newton,

Geek heroes

Brian Kernighan
Programmer and writer extraordinaire

Dennis Ritchie
Designer and original implementer of

Another geek hero

Kristen Nygaard
Co-inventor (with Ole-Johan Dahl) of Simula67 and of

Yet another geek hero

Alex Stepanov
Inventor of the STL and generic programming

Two extremes

Academic beauty/perfection/purity
Commercial expediency
The pressures towards both are immense
Both extremes must

Ideals

The fundamental aims of good design
Represent ideas directly in code
Represent independent

Ideals have practical uses

During the start of a project, reviews them

Ideals are personal

Chose yours well

Stroustrup/Programming

Styles/paradigms

Procedural programming
Data abstraction
Object-oriented programming
Generic programming
Functional programming, logic programming, rule-based programming, constraints-based

Styles/paradigms

template void draw_all(Iter b, Iter e)
{
for_each(b,e,mem_fun(&Shape::draw)); // draw all shapes

Styles/paradigms

template void draw_all(Cont& c) // C++11
{
for_each(Shape* p : c) p->draw(); //

Some fundamentals

Portability is good
Type safety is good
High performance is good
Anything that

Programming languages

Machine code
Bits, octal, or at most decimal numbers
Assembler
Registers, load, store,

Early programming languages

Classic C

Simula

Pascal

Algol68

BCPL

Fortran

Lisp

COBOL

Algol60

PL/I

1950s:

1960s:

1970s:

Red==major commercial use Yellow==will produce important “offspring”

Stroustrup/Programming

Modern programming languages

Object Pascal

C++

Java95

C#

Ada98

C++98

Java04

C++11

Python

Lisp

Smalltalk

Fortran77

Ada

Eiffel

Simula67

COBOL89

PHP

C89

Pascal

PERL

Visual Basic

COBOL04

Javascript

Stroustrup/Programming

Why do we design and evolve languages?

There are many diverse applications

First modern computer – first compiler

David Wheeler (1927-2004)
University of Cambridge
Exceptional problem

Early languages – 1952

One language for each machine
Special features for processor
Special

Fortran

John Backus (1924-2007)
IBM
FORTRAN, the first high level computer language to

Fortran – 1956

Allowed programmers to write linear algebra much as they

COBOL

“Rear Admiral Dr. Grace Murray Hopper (US Navy) was a remarkable

Cobol – 1960

Cobol was (and sometimes still is) for business programmers

Lisp

John McCarthy (1927-2011)
Stanford University
AI pioneer

Stroustrup/Programming

Lisp – 1960

List/symbolic processing
Initially (and often still) interpreted
Dozens (most likely hundreds)

Algol

Peter Naur (b. 1928)
Danish Technical University and Regnecentralen
BNF
Edsger Dijkstra (1930-2002)
Mathematisch Centrum,

Algol – 1960

The breakthrough of modern programming language concepts
Language description
BNF; separation

Simula 67

Kristen Nygaard (1926-2002) and Ole-Johan Dahl (1931-2002)
Norwegian Computing Center
Oslo University
The

Simula 1967

Address all applications domains rather then a specific domain
As Fortran,

C

Dennis Ritchie (1941-2011)
Bell Labs
C and helped with Unix
Ken Thompson (b. 1943)
Bell

Bell Labs – Murray Hill

Stroustrup/Programming

C – 1978

(Relatively) high-level programming language for systems programming
Very widely used,

C++

Bjarne Stroustrup
AT&T Bell labs
Texas A&M University
making abstraction techniques affordable and manageable

My ideals – in 1980 and more so in 2013

“To make

C++ – 1985

C++ is a general-purpose programming language with a bias