History of Programming Languages

Why study history?

• Something different
• Appreciation
• Inspiration

How to Look at History

• There are a few different ways programming language history is commonly explored
  • Genealogically
    • Attempts to derive more or less continuous lines of evolution from the earliest programming languages to today
  • Innovations
    • More concerned with major developments each language provided

From http://www.digibarn.com/collections/posters/tongues/ComputerLanguagesChart-med.png

Pre-Modern Era

• The ideas of automatic computation and programming are not recent
• In the 1800s
  • The programmable loom of Joseph Jacquard
  • Babbage's automatic difference engine
  • Ada Lovelace - widely considered first programmer

The Dawn Of Computing

• The earliest computers were not programmable in our sense of the word
  • Could not store programs
  • Were often hardware based

Plankalkul

• From the German "program calculus"
• Invented around 1945, but not published until 1972
• Each statement was two or three lines of code
  • Imagine writing fractions in ASCII only
• Also published were algorithms to sort arrays and other advanced problems

Shortcode

• One of the earliest programming languages
  • Was interpreted to machine code
• Mathmatical expressions assigned numbers
  • 06 - abs
  • 2x - x + 2nd root

    00 X0 03 20 06 Y0
    

The First Compilers

• Grace Hopper lead the team that built the first programs approximating compilers
• First produced in 1951, the A-0 compiler could comiple shortcode and other similar ecnoding schemes
  • Produced machine code to be run directly on the hardware
• Followed by the A-1 and A-2 systems
• Ran on the UNIVAC architecture

Fortran

• FORmula TRANslation
  • First version published in 1956
• One of the first high-level languages
  • The most successful and influential certainly
• Developed to run on the IBM 704
  • Had floating point and indexing capabilities!
• Still used for extremely fast mast applications to this day

Fortran Contributions

• Variables
• Expressions over numbers and booleans
• Fixed Length Arrays
• Reusable Subprograms (Functions)
• Input and Output Functionality

LISP

• Developed in the late 50s, specifically to support AI research
• Fotran had a list processing language that didn't support
  • Recursion
  • Conditional Expressions
  • Dynamic Length Lists
  • Garbage Collection
• LISP was highly influential, even if it was primarily limited to AI research labs in actual use

ALGOL

• An attempt to create and ALGOrithmic Language to run on any computer in the world
  • Including Backus and Naur
• Designed by a commitee made up of representatives from
  • German Society for Applied Mathmattics and Mechanics
  • Association for Computing Machinery
• Design began in 1957
  • Released in 1960

ALGOL 60 Contributions

• Blocks
• Type declarations
• Scope
• Nested If Statements
• Recursive Functions
• Dynamic Length Arrays

ALGOL's Legacy

• Conceptually is the basis for most modern languages
• Was never popular
  • Hard to implement
  • IBM didn't support it
• Put a damper on the general idea of design by committee

COBOL

• Still extremely widely used
  • Banks, Government
• Meant for data processing
  • Looks more "English"
• Design headed by the DoD
• First published in 1960

COBOL's Contributions

• File Descriptions
  • Input and Output support in General
• Words rather than obscure functions
• Records

PL/I

• Released in the mid 60s
  • Developed at IBM
• PL/I was meant to take what is best from Fortran, COBOL, and ALGOL
  • First example of really trying to combine different programming language features
• Ended up being very complex

PL/I Contributions

• Exception Statements
• Pointers
• External Linking

BASIC

• Created as a teaching tool in the early 1960's
  • Was still used in Montgomery County Public Schools in the early 2000s :)
• Later became popular as a basis for GUI programming
  • Visual Basic
• First language designed to be run remotely, rather than as a tape or cards fed directly to the machine

Simula

• Designed in Norway for use in simulating a computer
  • Simula I was released in 1964
• Simula 67 is the more influential version
  • Based on ALGOL 60
  • Supported co-routines
    • As a by-product of this, had methods of data abstraction

The Precurors to C

• The UNIX operating system aws in early development in the late 1960s
  • Common languages at Bell Labs at the time were BCPL, and an ever simpler version known as B
• Both were typeless
  • Integer or Floating Point Division
• C was first released in 1972
  • Borrowed a lot from ALGOL 68

The Popularity of C

• Didn't really introduce to many new features
• Was very flexible, and due to its use in the UNIX operating system, had a large audience
  • Also meant there was a easy to get compiler for many different computers!

Smalltalk

• Smalltalk is considered the first object oriented language
  • Was built out of a PhD Disseration from the University of Utah in 1969, by Alan Kay
• Developed at Xerox PARC
  • First published in 1972
• Everything is an object
  • All methods are called throug message passing

Smalltalk Contributions

• GUIS
  • Orginally meant as a way to abstract an interface away from code
• Object Oriented Programming
  • Inheritance

C++

• Developed at Bell Labs, just like the original C
  • At first was just another version of C with better type checking
• C with Classes was first published in 1983
  • C++ released in 1984
• Goals
  • Fast, a superset on top of C
  • Support classes and inheritance

The Impact of C++

• Although it borrowed from many other languages, it was many peoples first exposure to OOP
  • Because it kept most of the sytnax of C, a lot of people had a good place to start
• Continues to be used very widely today

Java

• Started as a way to embed code into consumer devices by Sun Microsystems
  • Originally a modified version of C++
• C++ was too dangerous in terms of what it allowed to be truly acceptable
  • Should be more reliable
  • Java doesn't allow functions outside of objects

Java Contributions

• First major language to not allow code to be compiled directly to machine code
• First major language to widely support multiple inheritance
• Its popularity spurred work on faster interpreters and VMs
  • The JVM was very slow at first

After Java

• The history of programming languages becomes an unruely field after Java
  • Part of the reason is we are still living in it
  • The internet and GitHub make it much easier to write and publish a language to thousands of users
• The large supportive community around a language is often as much of a factor about its popularity as the features of the language itself

Scripting Languages

• In general, all modern scripting languages are based on features found in the original shell in Unix, know as sh
• Most modern languages are scripting languages
  • This allows them to be written in a widely available lower language, like C
  • The compiler/interpreter only has to be written once