Erlang

@alepoletto

What is/ Why?• Functional programming language.

• Large emphasis on concurrency and high reliability

• Erlang's runtime system has built-in support for concurrency,

distribution and fault tolerance

• Use the Actor Model

• Used in telecoms, banking, e-commerce, computer telephony and

instant messaging.

• Runs inside a virtual machine.

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Who created?

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Reference to A. K. Erlang

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Who is using

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@alepoletto

Variables and Atoms

• X = 2 + 2.

• X = 4.

• X = 7.

• x = 4. (can’t be lower case)

• Lower case is reserved to atoms

• Lets say that car is a atom.

• Them car is a car nothing more.

• Useful to express values

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Functions

soma(A, B) -> A+B.

ola() -> io:format(“Ola”).

olaSoma(A) -> ola(), soma(A,1).

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Modules

-module(society).

-export([soma/2]).

-compile(export_all).

soma(A, B) -> A+B.

ola() -> io:format(“Ola”).

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Pattern Matcher

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Pattern Matching

function jovem(Pessoa)

if Pessoa == chaves then

print(“Jovem ainda”)

else if Pessoa == madruga then

print(“Velho”)

else

print(“Não sei")

end

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Pattern Matching

jovem(chaves) -> io:format(“Jovem ainda”);

jovem(madruga) -> io:format(“Velho”);

jovem(_) -> io:format(“Não Sei”).

adulto(X) when X >= 21 -> true;

adulto(_) -> false.

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Lets be Functional

fatorial(0) -> 1;

fatorial(N) -> when N > 0 -> N * fatorial(N-1).

map(_, []) -> [];

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

L = [1,2,3,4,5].

map(fun society:fatorial/1, L).

map(fun(X) -> X + 1 end, L).

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Actors

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Actors

cobra() ->receive

{From, speak} ->From ! “You're the disease, and I'm the

cure.";{From, deal} ->

From ! “I don't deal with psychos. I put them away. ";

_ ->io:format(“no talk")

end.

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Actors

Stallone = spawn(society, cobra, []).

<0.55.0>

Stallone! {self(), speak}.

flush().

"You're the disease, and I'm the cure. “

Stallone! {self(), danca}.

flush().

@alepoletto

Actors

cobra() ->receive

{From, speak} ->From ! “You're the disease, and I'm the cure."cobra();

{From, deal} ->From ! “I don't deal with psychos. I put them away. "cobra();

_ ->io:format(“no talk")cobra();

end.

@alepoletto

Actors

Stallone! {self(), speak}.

“You're the disease, and I'm the cure.“

Stallone! {self(), deal}.

“I don't deal with psychos. I put them away. “

Stallone! {self(), shoot}.

“no talk”

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Reference

• http://learnyousomeerlang.com/

• http://www.erlang.org/

• http://en.wikipedia.org/wiki/Erlang_(programming_language)

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Thank You

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