Erlang is a functional programming language created in 1986 at Ericsson for building distributed, fault-tolerant applications. It uses processes and message passing. Erlang is dynamically typed and supports variables, atoms, lists, tuples, pattern matching, functions, control structures like case/if, and concurrency through processes that communicate asynchronously. It is used in applications like RabbitMQ, Facebook Chat, GitHub, and AWS.

1. Erlang – What is it?
- created by Joe Armstrong in 1986 at Ericcsson Telecom
- based on Prolog
- functional language
- dynamicly typed
Author: Mateusz Zawisza

2. Where is it used?
- RabbitMQ (France Telecom)
- Facebook Chat
- GitHub (egitd)
- SampleDB (AWS)
Author: Mateusz Zawisza

3. Types - variables
Var = 2.
Var. %=> 2
Var = 3. % this throws an error!
Author: Mateusz Zawisza

4. Types - atoms
- same role as symbols in Ruby
- usually start with lower-case
this_is_atom
Author: Mateusz Zawisza

5. Types - lists
[1, 2, 3, 4]
Author: Mateusz Zawisza

6. Types - tuples
{a, 2,"d"}.
{ company,
{name, "Applicake",
{address, "Krakow"}
}
}.
Author: Mateusz Zawisza

7. Matching
Company = {company,
{name, "Applicake"},
{address, "Krakow"}
}.
{company,
{name, Name},
{address, Address}
} = Company.
Name %=> "Applicake"
Address %=> "Krakow"
Author: Mateusz Zawisza

8. Matching
[Head | Tail] = [1,2,3,4].
Head. %=> 1
Tail. %=> [2,3,4]
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9. Matching
[One, Two | Rest] = [1,2,3,4].
One. %=> 1
Two. %=> 2
Rest.%=> [3,4]
Author: Mateusz Zawisza

10. Functions
-module(mirror_function).
-export([mirror/1]).
mirror(Argument) -> Argument.
Author: Mateusz Zawisza

11. Functions
-module(matching_function).
-export([number/1]).
number(one) -> 1;
number(two) -> 2;
number(three) -> 3.
Author: Mateusz Zawisza

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

13. Functions
map(F, [H|T]) -> [F(H) | map(F, T)];
map(F, []) -> [].
Author: Mateusz Zawisza

14. Control sturctures...
case...
case Animal of
"dog" -> underdoga;
"cat" -> thundercat
_ -> something_else
end.
Author: Mateusz Zawisza

15. Control sturctures...
if...
if
X > 0 -> positive;
X < 0 -> negative;
true -> zero
end.
Author: Mateusz Zawisza

16. Processes
Pid = spawn(fun module_name:function_name/0).
Pid ! "message".
Author: Mateusz Zawisza

17. Processes
fuction_name() ->
receive
"message" ->
io:format("Hi!"),
function_name();
_ ->
io:format("Whatever..."),
function_name()
end.
Author: Mateusz Zawisza