Erlang (programming language)

For other uses, see erlang (disambiguation).

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. 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

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 precompiler to create a new module(library) called hello. This also tells us the name of the file: 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. printf is itself a function similar to main but predefined in a library (io) and linked into the program at compile time or runtime. The trailing period is the end of function marker in erlang.

See also

• prolog
• scheme