How Many Programming Languages are there in this World? CS 199 Computers Unplugged. What is a Programming Language? What is a Programming Language?

Transcription

1 CS 199 Computers Unplugged Course Notes 1 Week 4: Natural and Programming Languages Lecture 2: Programming Languages How Many Programming Languages are there in this World? Anton Setzer csetzer/index.html csetzer/lectures/ computersunplugged/10/index.html Number of languages linked from at HOPL: Same problems as for natural languages: Families of languages. Dialects. Different versions. Different compilers for the same language execute differently. November 5, Substantially based on Stephen Anderson: How many languages are there in the world. Available from files/howmany.pdf CS 199 1/ 30 What is a Programming Language? CS 199 2/ 30 What is a Programming Language? The Free Dictionary An artificial language used to write instructions that can be translated into machine language and then executed by a computer. Wikipedia language A programming language is an artificial language designed to express computations that can be performed by a machine, particularly a computer Britannica Online Computer programming language, any of various languages for expressing a set of detailed instructions for a digital computer. Webopedia language.html A vocabulary and set of grammatical rules for instructing a computer to perform specific tasks CS 199 3/ 30 CS 199 4/ 30

2 What is a Programming Language? What is a Language? My definition: A programming language is a set of descriptions such that each description can be used to instruct a computer or other mechanical device to perform a specific task. An alphabet is a finite set. A formal language is a set of strings over a given alphabet. CS 199 5/ 30 CS 199 6/ 30 What is a Programming Language? Adjustment Mechanism of a Mechanical Watch An Analogue Programming Language Is mp3 a programming language? Analogue computer languages. Not formal languages. Is English a programming language? CS 199 7/ 30 CS 199 7a/ 30

3 Vynil Record Analogue Programming Language Antikythera Mechanism CS 199 7b/ 30 CS 199 8/ 30 Antikythera Mechanism CS 199 9/ 30 Antikythera Mechanism (around BCE) From programming: The Antikythera mechanism from ancient Greece was a calculator utilizing gears of various sizes and configuration to determine its operation, which tracked the metonic cycle still used in lunar-to-solar calendars, and which is consistent for calculating the dates of the Olympiads. From Mark Wonnacott: Analogue Computers: The First Declarative Programming. The first machine computable delcarative program is within the earliest mechanical computer, the Antikythera mechanism (c. 70 BC). Changing the date with the mechanism s hand-crank turned a complex arrangement of gears to compute astronomical positions. Different gearing rations between connected gears dictate the relationships between them and ultimately between the date and calculated astronomical positions. These relationships are invariantly satisfied by the turning of the gears, making the gears a form of declarative program. CS / 30

4 Al-Jazari Musical Robots A Digital Programming Language History of Programming Languages Wikipedia, l-jazari created a musical automaton, which was a boat with four automatic musicians that floated on a lake to entertain guests at royal drinking parties. Professor Noel Sharkey has argued that it is quite likely that it was an early programmable automata and has produced a possible reconstruction of the mechanism; it has a programmable drum machine with pegs (cams) that bump into little levers that operated the percussion. The drummer could be made to play different rhythms and different drum patterns if the pegs were moved around. According to Charles B. Fowler, the automata were a robot band which performed more than fifty facial and body actions during each musical selection. CS / 30 CS / 30 Jacquard Loom (Invented 1801) Babbage s Analytical Engine (1834) Jacquard Loom, invented by Joseqph Marie Jacquard 1801 CS / 30 CS / 30

5 Babbage s Analytical Engine First Turing Complete Language Ada Lovelace - The first Computer Programmer It s Turing complete. More in CS-236 Lanugage and Computation. Any computable function can be computed in principle using Babbage s Analytical Engine. The language for Babbage s Analytical Engine is probably the first Turing-Complete Programming Language. CS / 30 CS / 30 Hello World Program 99 Bottles of Beer CS / 30 CS / 30

6 Popular Languages Scripting Languages Java C C++ Pascal Perl Python CS / 30 CS / 30 Easy to Use Languages Functional Programming Languages BASIC Visual Basic Haskell SML Coq (dependently typed) CS / 30 CS / 30

7 Logic Programming Markup Languages/Spreadsheets Prolog HTML Excel CS / 30 CS / 30 Misc Historically Famous Languages Database Languages SQL Graphical Languages LabVIEW Babbage s Analytical Language ENIAC FORTRAN LISP Cobol Simula CS / 30 CS / 30

8 Assembler Theoretical Languages Turing Machine CSP CS / 30 CS / 30 Extreme Languages Esoteric Languages SheerPower. Aimed at having the fastest compilation. What does this mean? Brainfuck. Aimed at having thesmallest compiler. What does this mean? Malbolge Aimed at having the most incomprehensible language. Cow. LOLCODE. Piet. Whitespace. CS / 30 CS / 30