Learning Erlang

Ivan YatskevichLead Software Engineer, EPAM

Learn at least one new language every year.

Tip 8: Invest Regularly in Your Knowledge Portfolio

Sequential Erlang

Distributed Erlang

Parallel Erlang

OTP Framework

Part I: Sequential ErlangData types, modules, functions, variables and pattern matching

Data types

• Numbers 12, 2#10, 16#FF, 2.76

• Atomsok, false, summer, ‘Wednesday’

• Bit strings and binaries<<“Are you sure?”>>, <<45, 19, 4>>

Data types (cont’d)

• Containers (Lists, Tuples)List = [1, true, “Erlang”]Tuple = {io, format, [“~p~n”]}

• FunctionsTripler = fun(N) -> N*3 end

• Identifiers (Refs, Pids, Ports)

(Fake) Data types

• Booleantrue, false

• String“ABC” = [65, 66, 67]

• Record (≈tuple)

Building blocks

• Modules• Functions• Clauses• Guards• MFA• BIFs

• Control structures• Case, If• Catch

Variables and Matching

Index ≠ Index + 1

{ "data": { "translations": [ { "translatedText": "Hallo Welt" } ] }}

Variables and Pattern MatchingTranslation = {data, {translations, [ {translatedText, "Hallo Welt"} ] }}.{data, {translations, [ {translatedText, Text}|Tail ] }} = Translation.

Variables and Pattern MatchingTranslation = {data, {translations, [ {translatedText, "Hallo Welt"} ] }}.

{_, {_, [{_, Text}|_]}} = Translation.

Part II: Distributed ErlangNodes, net_adm module, a lot of fun

LAN

Distributed Erlang

• Nodes$ erl –name nyan_cat@127.0.0.1

• Cookies$ erl –sname nyan_cat –setcookie secret

• net_adm:pingerl> net_adm:ping(tom_cat@192.168.32.4).

Part III: Parallel ErlangProcesses, Pids, message passing

Parallel Erlang

• ProcessesPid = spawn(fun() -> hi end).

• Sending messagePid ! {any_message, [“with”, list]}.

• Receiving messagereceive

Pattern1 -> action1;Pattern2 -> action2

after TimeInMs ->

action_after_timeoutend.

Parallel Erlang (cont’d)

• self()• make_ref()• System process and linking• Named processregister(name_as_atom, Pid).

Part IV: OTP FrameworkOverview

OTP Framework

http://learnyousomeerlang.com/what-is-otp

Resources

• http://www.erlang.org• http://www.tryerlang.org• http://learnyousomeerlang.com• http://www.trapexit.org/• Programming Erlang, by Joe Armstrong• Erlang Programming, by Francesco Cesarini and Simon

Thompson• Erlang and OTP in Action, by

Martin Logan, Eric Merritt, and Richard Carlsson• http://nyan.cat

Thank you!

Q & A