# my_script.exs

defmodule MyModule do def my_func do IO.puts("Hello, world!") endend

MyModule.my_func()

gmile@macbook ~> elixir my_scriptHello, world!

gmile@macbook ~> iexiex(1)> c “my_script.exs”[MyModule]iex(1)> MyModule.my_func"Hello, world!”:ok

defmodule MyModule do def my_func(1), do: "Got one!" def my_func(2), do: "Got two!" def my_func(n), do: "Got #{n}!"end

IO.puts(MyModule.my_func(10))IO.puts(MyModule.my_func(5))IO.puts(MyModule.my_func(2))IO.puts(MyModule.my_func(1))

defmodule MyModule do def my_func(1), do: "Got one!" def my_func(2), do: "Got two!" def my_func(n), do: "Got #{n}!"end

MyModule.my_func(10) |> IO.putsMyModule.my_func(5) |> IO.putsMyModule.my_func(2) |> IO.putsMyModule.my_func(1) |> IO.puts

defmodule MyModule do def my_func(a_thing) when is_list(a_thing) do "Got a list!” end

def my_func(a_thing) when is_integer(a_thing) do "Got a number!” end

def my_func(_) "Got something else!” endend

MyModule.my_func([1,2,3]) # => “Got a list!”MyModule.my_func(369) # => “Got a number!”MyModule.my_func(“yo”) # => “Got something else!”

defmodule MyModule do def match_a_list([head|tail]) do IO.puts(“First element is #{head}!”) endend

defmodule MyModule do def match_a_list([one, two|tail]) do IO.puts(“First element is #{one}!”) IO.puts(“Second element is #{two}!”) match_a_list(tail) endend

defmodule MyModule do def match_a_list([]) do IO.puts(“A list is empty!”) end

def match_a_list([one, two|tail]) do IO.puts(“First element is #{one}!”) IO.puts(“Second element is #{two}!”) match_a_list(tail) endend

defmodule MyModule do def match_a_list([one, two|tail]) do IO.puts(“First element is #{one}!”) IO.puts(“Second element is #{two}!”) endend

defmodule MyModule do def match_a_list([{_,b,_}|tail]) do IO.puts(“First element is a tuple”) IO.puts(“Tuple’s second element is #{b}”) endend

defmodule MyModule do def match_a_list([t = {_,b,_}|tail]) do IO.puts(“First element is a tuple of size 3”) IO.puts(“Tuple’ss second element is #{b}”) endend

defmodule Anagram do def match(base, candidates) do base_ = String.downcase(base) fingerprint = fingerprint(base_)

Enum.filter(candidates, fn(candidate) -> cand_ = String.downcase(candidate) cand_ != base_ && fingerprint(cand_) == fingerprint end) end

def fingerprint(string) do string |> String.codepoints |> Enum.sort endend

Kyiv, July 2016

Introduction toElixir & Erlang

VM

Kiev, 2016

Erlang.Brief history and facts

Erlang VM.An overview of languages on BEAM

Elixir.Brief history and ecosystem overview

Who created Erlang?

Who uses Erlang in production?

How old is erlang?

version 1.03 “lost in

the mists of time”

version 1.06 dated 1986-12-18

Who supports erlang today?

How many packages are there?

470!

What are some of the most popular

libs/projects?

How many popular projects

are there, per GitHub?

What exactly erlang is?

erlang a mathematician

a measurement unit

a programming language

erlang the language itself (syntax)

the OTP framework

the virtual machine

-module(hello).-export([hello_world/0]).

hello_world() -> io:fwrite("hello, world\n").

Eshell V8.0.1 (abort with ^G)1> c(hello).{ok,hello}2> hello:hello_world().hello, worldok

-module(count_to_ten).-export([count_to_ten/0]). count_to_ten() -> do_count(0). do_count(10) -> 10;do_count(Value) -> do_count(Value + 1).

Open Telecom Platform

OTP ~~~ It’s a framework ~~~

a set of design principles

a set of tools

BEAM

What is BEAM?

BEAM a name for virtual machine

binary file format

file extension, e.g. .beam

Before BEAM Warren Abstract Machine, WAM

Joe’s Abstract Machine, JAM

Bogdan's Erlang Abstract Machine

Bogdan/Björn's Erlang Abstract

Machine

Current version is R19

Line numbersin exceptions,

woohoo!!!

What kind of virtual machine

BEAM is?

What is M in VM?

{module, add}. %% version = 0{exports, [{add,2},{module_info,0},{module_info,1}]}.{attributes, []}.{labels, 9}.

{function, add, 2, 2}. {label,1}. {line,[{location,"add.erl",6}]}. {func_info,{atom,add},{atom,add},2}. {label,2}. {allocate,1,2}. {move,{x,1},{y,0}}. {line,[{location,"add.erl",7}]}. {call,1,{f,4}}. {move,{x,0},{x,1}}. {move,{y,0},{x,0}}. {move,{x,1},{y,0}}. {line,[{location,"add.erl",7}]}. {call,1,{f,4}}. {line,[{location,"add.erl",7}]}. {gc_bif,'+',{f,0},1,[{y,0},{x,0}],{x,0}}. {deallocate,1}. return.

{function, id, 1, 4}. {label,3}. {line,[{location,"add.erl",9}]}. {func_info,{atom,add},{atom,id},1}. {label,4}. return.

{function, module_info, 0, 6}. {label,5}. {line,[]}. {func_info,{atom,add},{atom,module_info},0}. {label,6}. {move,{atom,add},{x,0}}. {line,[]}. {call_ext_only,1,{extfunc,erlang,get_module_info,1}}.

{function, module_info, 1, 8}. {label,7}. {line,[]}. {func_info,{atom,add},{atom,module_info},1}. {label,8}. {move,{x,0},{x,1}}. {move,{atom,add},{x,0}}. {line,[]}. {call_ext_only,2,{extfunc,erlang,get_module_info,2}}.

-module(add).

-export([add/2]).

add(A, B) -> id(A) + id(B).

id(I) -> I.

158 instructions

Write your own language that compiles to

BEAM!

So: what languages run on BEAM?

But before Elixir…

Jose Valim

Who created Elixir?

How old is Elixir?

Who supports Elixir today?

What is Elixir?

Functional Concurrent

General-purpose programming

language

Supports:metaprogramming

via macrospolymorphism via

protocols

How many packages are there?

How many popular projects

are there, per GitHub?

What are some of the most popular

libs?

Who uses Elixir in production?

What Joe Armstrong thinks of Elixir?

> Elixir has a non-scary syntax and combines the

good features of Ruby and Erlang.

> It's not Erlang and it's not Ruby and it has ideas of its

own.

What Elixir offers?

defmodule MathTest do use ExUnit.Case, async: true

test "can add two numbers" do assert 1 + 1 == 2 endend

import Supervisor.Spec

children = [ supervisor(TCP.Pool, []), worker(TCP.Acceptor, [4040])]

Supervisor.start_link(children, strategy: :one_for_one)

parent = self()

# Spawns an Elixir process (not an OS process!)spawn_link(fn -> send parent, {:msg, "hello world"}end)

# Block until the message is receivedreceive do {:msg, contents} -> IO.puts contentsend