Erlang: Las Sagas Nórdicas

Introducción a Erlang

Transcript

1. Erlang/OTP Las Sagas Nórdicas Julián David Duque Organizador MedellínJS Ingeniero NodeSource @julian_duque - http://about.me/julianduqe
2. Erlang El Lenguaje
3. Erlang es un lenguaje funcional de propósito general, especial para aplicaciones concurrentes, distribuidas y tolerantes a fallos
4. Los procesos en Erlang son un concepto fundamental Una aplicación Erlang se puede dividir en múltiples procesos que corren aislados en la máquina virtual
5. Características del Lenguaje
6. Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> 42. 42 2> 1 + 1. 2 3> 45 - 3. 42 4> "Thor". "Thor" 5> Cada sentencia termina en `.` Erlang Shell (erl)
7. Tipos de datos Números (enteros y punto flotante) Binarios / Bitstrings Atoms Tuples Listas (y strings) Identificadores Únicos (Pids, Ports, References) Funs
8. Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> 42. 42 2> -42. -42 3> 16#FF6600. 16737792 4> 2#101101. 45 5> $9. 57 6> 3.141592. 3.141592 7> 1.68e23. 1.68e23 8> Números
9. Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> Name = "Thor". "Thor" 2> Name = "Loki". ** exception error: no match of right hand side value "Loki" 3> Name. "Thor" 4> "Thor" = Name. "Thor" 5> Variables con primera letra mayúscula Todas las variables son inmutables Variables
10. Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> << "hello", 32, "my", 32, "name", 32, "is", 32, "Thor" >>. <<"hello my name is Thor">> 2> << 255, 0, 0 >>. <<255,0,0>> 3> Binary / Bitstrings Secuencias de bytes Usados para guardar `chunks` de información
11. Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> name. name 2> ok. ok 3> error. error 4> error = error. error 5> error == error. true 6> ok == error. false 7> El nombre del atom es su mismo valor Atoms en Erlang se escriben en minúscula Atoms
12. Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> {1, 2, 3}. {1,2,3} 2> {one, two, three}. {one,two,three} 3> {name, “Thor”, weapon, “Mjolnir”}. {name,”Thor”,weapon,”Mjolnir”} 4> {ok, "Everything is fine in Midgard"}. {ok,"Everything is fine in Midgard"} 5> {point, 0, 0}. {point,0,0} 6> {point, 10, -10}. {point,10,-10} 7> Secuencia de términos Erlang Tuples
13. Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> [1, 2, 3]. [1,2,3] 2> []. [] 3> [one, two, three]. [one,two,three] 4> [[1,2,3],[4,5,6]]. [[1,2,3],[4,5,6]] 5> [{name, "Thor"}, {weapon, "Mjolnir"}]. [{name,"Thor"},{weapon,"Mjolnir"}] 6> El tipo de dato más importante de Erlang en cuanto a su aspecto funcional Listas
14. Identificadores Únicos Pids (Identificador de Procesos) Ports (Identificador de Puertos) Son como Pids pero son usados para comunicación con el mundo exterior References creados con la función make_ref() sirven como identificadores únicos o cookies.
15. Funs Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> Add = fun(A, B) -> A + B end. #Fun<erl_eval.12.54118792> 2> Add(39, 3). 42 3> Funciones anónimas (lambda o closure)
16. Módulos y Funciones Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> c("thor.erl"). {ok,thor} 2> thor:smash(). I will smash you with my hammer ok 3> thor:smash("Loki"). I will smash "Loki" with my hammer ok 4> -module(thor). -export([smash/0, smash/1]). smash() -> io:format("I will smash you with my hammer~n"). smash(Target) -> io:format("I will smash ~p with my hammer~n", [ Target ]).
17. Pattern Matching Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> Name = "Thor". "Thor" 2> "Thor" = Name. "Thor" 3> Name = "Loki". ** exception error: no match of right hand side value "Loki" 4> {god, Name, Weapon} = {god, "Thor", "Mjolnir"}. {god,"Thor","Mjolnir"} 5> Name. "Thor" 6> Weapon. "Mjolnir" 7>
18. Pattern Matching (Funciones) -module(maths). -export([add/1, add/2]). add(A, B) -> A + B. add({A, B}) -> A + B; add([A, B]) -> A + B.
19. Pattern Matching (Funciones) Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> c("maths.erl"). {ok,maths} 2> maths:add(2, 3). 5 3> maths:add({2, 3}). 5 4> maths:add([2, 3]). 5 5> maths:add([2, 3, 4]). ** exception error: no function clause matching maths:add([2,3,4]) (maths.erl, line 7) 6>
20. Pattern Matching (Case … of) -module(thor). -export([smash/0, smash/1]). smash() -> io:format("I will smash you with my hammer!~n"). smash(Target) -> case Target of {family, Name} -> io:format("I will not fight against ~p~n", [Name]); {enemy, Name} -> io:format("I will smash ~p with my hammer~n!", [Name]); _ -> smash() end.
21. Pattern Matching (Case … of) Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> c("thor.erl"). {ok,thor} 2> thor:smash({family, "Odin"}). I will not fight against "Odin" ok 3> thor:smash({enemy, "A Frost Giant"}). I will smash "A Frost Giant" with my hammer !ok 4> thor:smash("Someone else"). I will smash you with my hammer! ok 5>
22. Function Guards Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> c("maths.erl"). {ok,maths} 2> maths:add(1,2). 3 3> maths:add("1", "2"). ** exception error: no function clause matching maths:add("1","2") (maths.erl, line 4) 4> -module(maths). -export([add/2]). add(A, B) when is_number(A) and is_number(B) -> A + B.
23. Function Guards Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> erlang:is_ is_alive/0 is_atom/1 is_binary/1 is_bitstring/1 is_boolean/1 is_builtin/3 is_float/1 is_function/1 is_function/2 is_integer/1 is_list/1 is_map/1 is_number/1 is_pid/1 is_port/1 is_process_alive/1 is_record/2 is_record/3 is_reference/1 is_tuple/1 Además de otros condicionales y operaciones
24. Recursividad -module(maths). -export([factorial/1]). factorial(0) -> 1; factorial(N) when N > 0 -> N * factorial(N - 1). Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> c("maths.erl"). {ok,maths} 2> maths:factorial(0). 1 3> maths:factorial(1). 1 4> maths:factorial(6). 720
25. Recursividad -module(maths). -export([sum/1]). sum([]) -> 0; sum([Head | Tail]) -> Head + sum(Tail). Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> c("maths.erl"). {ok,maths} 2> maths:sum([]). 0 3> maths:sum([1]). 1 4> maths:sum([1,2]). 3 5> maths:sum([1,2,3]). 6 6>
26. Procesos Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> Pid = self(). <0.33.0> 2> Pid ! "Hello". "Hello" 3> Pid ! "World". "World" 4> flush(). Shell got "Hello" Shell got "World" ok 5>
27. Procesos -module(processes). -export([run/0, ping/0]). run() -> Pid = spawn(fun ping/0), Pid ! self(), receive pong -> ok end. ping() -> receive From -> From ! pong end.
28. Procesos Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> c("processes.erl"). {ok,processes} 2> processes:run(). ok
29. Procesos -module(thor_process). -export([start/0]). start() -> Pid = spawn(fun smash/0), {ok, Pid}. smash() -> receive {family, Name} -> io:format("I will not fight against ~p~n", [Name]); {enemy, Name} -> io:format("I will smash ~p with my hammer~n!", [Name]); _ -> io:format("I will smash you with my hamer~n!") end, smash().
30. Procesos Erlang/OTP 18 [erts-7.1] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false] [dtrace] Eshell V7.1 (abort with ^G) 1> c("thor_process.erl"). {ok,thor_process} 2> {ok, Pid} = thor_process:start(). {ok,<0.40.0>} 3> Pid ! {family, "Odin"}. I will not fight against "Odin" {family,"Odin"} 4> Pid ! {enemy, "Frost Giant"}. I will smash "Frost Giant" with my hammer !{enemy,"Frost Giant"} 5> Pid ! nothing. I will smash you with my hamer !nothing 6>
31. OTP La Plataforma
32. OTP (Open Telecom Platform) Es la plataforma (o framework) detrás de Erlang
33. OTP (Open Telecom Platform) Define el SASL (System Architecture Support Libraries) Un conjunto de librerías y patrones de diseño para escribir aplicaciones en Erlang
34. OTP (Open Telecom Platform) Behaviours, son los patrones de diseño para escribir aplicaciones en Erlang/OTP application gen_server gen_fsm gen_event supervisor
35. Gen_Server -module(...). -behaviour(gen_server). -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]). -record(state, {}). init([]) -> {ok, #state{}}. handle_call(_Request, _From, State) -> Reply = ok, {reply, Reply, State}. handle_cast(_Msg, State) -> {noreply, State}. handle_info(_Info, State) -> {noreply, State}. terminate(_Reason, _State) -> ok. code_change(_OldVsn, State, _Extra) -> {ok, State}. Instancia con start o start_link
36. BEAM La Máquina Virtual
37. Permite ejecutar Erlang (y otros lenguajes que compilan a BEAM como LFE y Elixir) Interfaces al mundo exterior (NIFs, Ports) Funciones incluidas en la VM (BIFs) (erlang:*) Erlang Virtual Machine (BEAM)
38. Ligero Comunicación Asíncrona Aislamiento de Procesos Manejo de Errores (Let it crash) Evolución Continua del Sistema (Hot reloading) Tiempo Real Caracteristicas
39. Eric Demo https://github.com/julianduque/eric https://github.com/julianduque/erlang-color
40. Muchas Gracias