Erlang (programming language)

For other uses, see erlang (disambiguation).

Erlang is a general-purpose, functional computer programming language which shares some syntax with prolog. 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. http://www.erlang.org/download/armstrong_thesis_2003.pdf New versions are released by Ericsson on a yearly basis. At present there is increased interest in parallel programming languages because of the spread of multicore microprocessor based personal computers.

Syntax

Hello World

-module(hello).
-export([start/0]).

start() ->
   io:format("Hello, world!\n").

Analysis of the example

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.

-module(hello) tells the compiler to create a new module(library) called hello. The code tells us the file name for this code: hello.erl.

-export([start/0]). exports a function named start with 0 arguments to the world outside of this module called hello.

start() -> tells the compiler that there is a function named start() with no arguments.

io:format("Hello, world!\n"). will make the program output Hello, world! and a new line (\n) on the screen.

See also

• prolog
• scheme