Erlang

What is it?

created by Joe Armstrong in 1986 at Ericcsson Telecom

based on Prolog

functional language

dynamicly typed

Erlang is...

reliable

high concurrent (no threads. light processes)

modular

Where is it used?

RabbitMQ (France telecom)

CouchDB

Facebook Chat

GitHub (egitd)

SimpleDB (AWS)

Types

Variables

Var = 2.

Var.%=> 2

Var = 3. % this throws an error!

atoms

this_is_atom

Lists

[1,2,3,4]

Tuples

{a, 2,"d"}.

{ company, {name, "Applicake", {address, "Krakow"}}}.

Matching

Company = {company, {name, "Applicake"}, {address, "Krakow"} }.

{company, {name, Name, {address, Address}}} = Company.

Name %=> "Applicake"Address %=> "Krakow"

Matching

[Head | Tail] = [1,2,3,4].

Head. %=> 1Tail. %=> [2,3,4]

Matching

[One, Two | Rest] = [1,2,3,4].

One. %=> 1Two. %=> 2Rest.%=> [3,4]

functions

-module(mirror_function).-export([mirror/1]).

mirror(Argument) -> Argument.

functions

-module(matching_function).-export([number/1]).

number(one) -> 1;number(two) -> 2; number(three) -> 3.

functions

Numbers = [1,2,3,4].

lists:map(fun(X) -> X+1 end, Numbers).%=> [2,3,4,5]

functions

map(F, [H|T]) -> [F(H) | map(F, T)];map(F, []) -> [].

Control structures

case...

case Animal of "dog" -> underdoga; "cat" -> thundercat _ -> something_else end.

Control structures

if...

if X > 0 -> positive; X < 0 -> negative; true -> zeroend.

Processes

Processes

Pid = spawn(fun module_name:function_name/0).

Pid ! "message".

Processes

fuction_name() -> receive "message" -> io::format("Hi!"), function_name();

_ -> io::format("Whatever..."), function_name()

end.