Erlang (programming language): Difference between revisions

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''For other uses, see [[erlang (disambiguation)]].''
{{dambigbox|Erlang (programming language)|Erlang}}
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'''erlang''' is a general-purpose, functional [[computer]] [[programming language]] which shares more with prolog than any other language. It was designed specificly to do parallel programming.  
The '''Erlang programming language''' is a [[strict]] [[functional language]], a  [[Programming_language#Declarative_vs._Imperative|declarative language]], and a [[Programming_language#General_purpose_vs._special_purpose|general-purpose ]] [[programming language]] which shares some syntax with [[prolog]]. It is considered declarative because it has the pattern matching syntax of prolog and list comprehensions. Because of its prowess at parallel programming it is particulary good at creating servers such as web servers or ftp servers with small amounts of code. It is a dynamically typed language. Armstrong also describes it as a concurrency oriented language. '''Erlang''' was developed in 1987 by [[Joe Armstrong]] and others (then of [[Ericsson]]) for use to program telephone networks. Ref: Joe Armstrong (2003). "Making reliable distributed systems in the presence of software errors". Ph.D. Dissertation. <ref Name=ArmDis>[http://www.erlang.org/download/armstrong_thesis_2003.pdf Armstrong Dissertation]</ref> New versions of Erlang are released by Ericsson on a yearly basis. At present(2008) there is increased interest in parallel programming languages because of the use of [[multicore]] microprocessors in personal computers. <ref Name=ConRev>[http://www.ddj.com/cpp/184401916 Multi-Core]</ref>
which is still in use more than thirty years after its creation. '''erlang''' was developed in 1987 by [[Joe Armstrong]] and others (then of [[Eriksonn]]) for use to program telephone networks. Ref: Joe Armstrong (2003). "Making reliable distributed systems in the presence of software errors". Ph.D. Dissertation. http://www.erlang.org/download/armstrong_thesis_2003.pdf
New versions are released by Ericsson on a yearly basis.


==Syntax==
==Syntax==
Functions are defined by the domain of the arguments and the number of arguemnts. A function ends with a period. A function over a particular domain of values is separated by a semicolon.


===Hello World===
fact(0) -> 1;
fact(N) when is_integer(N) ->
    fact(N-1)*N.


-module(hello).
Extensive Tutorial available: [[Erlang_programming_language/Tutorials]]
-export([start/0]).
start() ->
    io:format("Hello, world!\n").


====Analysis of the example====
==See also==


The [[Hello World]] program (see above) appears in many programming languages books and articles as a cursory introduction into a language's [[syntax]]. It was introduced in the book ''The C Programming Language''<ref name="K&R"/>.
* [[Prolog]]
* [[Scheme programming language|Scheme]]


<code>-module(hello)</code> tells the [[precompiler]] to create a new module(library) called hello. This also tells us the name of the file: hello.erl.
==Programs written in erlang==
 
<code>-export([start/0]). </code> exports a function named start with 0 arguments to the world outside of this module called hello.
 
<code> start() -> </code> tells the compiler that there is a [[function]] named start with no arguments.
 
<code>io:format("Hello, world!\n").</code> will make the program output <code>Hello, world!</code> and a new line (<code>\n</code>) on the screen. <code>printf</code> is itself a function similar to <code>main</code> but predefined in a library (io) and [[linker|linked]] into the program at compile time or runtime. The trailing period is the end of function marker in erlang.
==See also==


* [[prolog]]
* [[CouchDB]]: A document oriented database is an optional part of Apache. It is a distributed, schema-free and fault tolerant database.
* [[scheme]]
* [[Wings3d]]: A 3d design program.


==References==
==References==
<references/>
<references/>

Latest revision as of 14:53, 18 March 2024

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https://en.citizendium.org/wiki/index.php?title=Erlang_(programming_language)&printable=yes
This editable Main Article is under development and subject to a disclaimer.
This article is about Erlang (programming language). For other uses of the term Erlang, please see Erlang (disambiguation).

The Erlang programming language is a strict functional language, a declarative language, and a general-purpose programming language which shares some syntax with prolog. It is considered declarative because it has the pattern matching syntax of prolog and list comprehensions. Because of its prowess at parallel programming it is particulary good at creating servers such as web servers or ftp servers with small amounts of code. It is a dynamically typed language. Armstrong also describes it as a concurrency oriented language. Erlang was developed in 1987 by Joe Armstrong and others (then of Ericsson) for use to program telephone networks. Ref: Joe Armstrong (2003). "Making reliable distributed systems in the presence of software errors". Ph.D. Dissertation. [1] New versions of Erlang are released by Ericsson on a yearly basis. At present(2008) there is increased interest in parallel programming languages because of the use of multicore microprocessors in personal computers. [2]

Syntax

Functions are defined by the domain of the arguments and the number of arguemnts. A function ends with a period. A function over a particular domain of values is separated by a semicolon. 

fact(0) -> 1;
fact(N) when is_integer(N) -> 
    fact(N-1)*N.

Extensive Tutorial available: Erlang_programming_language/Tutorials

See also

Programs written in erlang

  • CouchDB: A document oriented database is an optional part of Apache. It is a distributed, schema-free and fault tolerant database.
  • Wings3d: A 3d design program.

References

  1. ↑ Armstrong Dissertation
  2. ↑ Multi-Core
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