Erlang is a functional programming language well-suited for building distributed, fault-tolerant systems. It uses processes and message passing rather than shared memory. Processes communicate asynchronously by exchanging immutable messages and can be distributed across multiple machines. The language supports features like pattern matching, immutable data, concurrency, distribution and hot code loading. Core abstractions include processes, message passing, and the supervision tree pattern for fault tolerance.

1. Erlang
@ino_murko
@ino_murko
Preaching to the Unconverted. #ruby vs. #erl

4. @iamdevloper
Speed dating is useless. 30s isn't long enough to explain the benefits of functional programming i
Extremely high number of concurrent processes.
The system can be distributed over multiple computers.
System has to be self repairing and self configurable.
tware maintenance must be performed without system shutdo
ACTOR MODEL

5. Share nothing
Immutable state
Pure async message passing
Event (Message) driven
Distributed
Concurrent
Soft real time
Dynamic code upgrade
Joe Armstrong @React 20

6. supervisors
worker
s
OTP behaviours
• set of design patterns
• gen_server, fsm, supervisor
server
process
message

7. @christinacaci
Programming is the surest way I know to feel brilliant one second and idiotic the
Syntax
area({square, Size}) ->
Size * Size;
area({circle, Radius})->
Pi = 3.14,
Pi * Radius * Radius;
area(_Unknown)->
error.

8. Syntax
Function head pattern matching
@znmeb
Functional programming is no more a silver bullet than anything else. The discipline > th
ey:Length/binary-unit:8, _Rem/binary>> = _DataRecv, Socket, State=#state{socket=
%do something;
ey:Length/binary-unit:8, _Rem/binary>> = _DataRecv, Socket, State=#state{socket=
%do something else.

9. Syntax
Single assignment
>1 = 1.
>1 = 2. %** exception error: no match of right hand side value
>X = X +1. %** exception error: no match of right hand side value
>Var = 1.
>{person,[{name,First},{last,Last}]}={person,[{name,”Roman”},{last,”R
>First.
"Roman"
>Last.
"Radovic"
@znmeb
Functional programming is no more a silver bullet than anything else. The discipline > th

10. Types (or lack thereof)
>F = fun(X,Y)->
X1 = X * 2,
Y1 = Y * X,
X1 +Y1
end.
#Fun<erl_eval.12.90072148>
>F(5, 6).
40.
@CompSciFact
The naming of functions is a difficult matte

11. If statement
if
A == 5 ->
do();
true ->
do_something_else()
end.
case Temperature of
{celsius, N} when N >= 20, N =< 45 ->
'favorable';
{kelvin, N} when N >= 293, N =< 318 ->
'scientifically favorable';
{fahrenheit, N} when N >= 68, N =< 113 -
'favorable in the US';
_ ->
'avoid beach'
end.
@t_sloughter
Writing large fault-tolerant systems in Java creates work for 5 people later. So use

12. Recursion :)
fact(0)->
1;
fact(N) when N > 0 ->
N * fact(N-1).
fact(Value)->
fact_help(lists:seq(1,Value),1).
fact_help([0],Acc)->
Acc;
fact_help([],Acc)->
Acc;
fact_help([H|T], Acc) when H > 0 ->
Acc0 = H * Acc,
fact_help(T, Acc0).
tail-recursiveNOT tail-recursive

13. Spawning processes and communication
@ jfcloutier
Prolog: thinking in proofs Erlang: thinking in processes UML: wishful thin
-module(hello_world).
-export([start/0]).
start()->
spawn(fun()-> respond() end).
respond()->
receive
hi->
io:fwrite("Hello World! ~n"),
respond();
stop ->
exit(normal)
end.

14. Spawning processes and communication
@ jfcloutier
Prolog: thinking in proofs Erlang: thinking in processes UML: wishful thin
receive
{start}->…
{stop}->…
{data,X,Y}->…
end
Pid ! {data, 12, 14}

16. ActorDB
@ino_murko

18. ACTOR emit_cloud_user(1013) CREATE;
SELECT * FROM file;
ACTOR emit_cloud_user(*);
INSERT INTO dir VALUES ('mapa');
ACTOR emit_cloud_user(1013,1014,1015);
{{RESULT}}SELECT * FROM file;
ACTOR emit_cloud_user(*);
PRAGMA LIST;

19. counters:
type: kv
schema:
- CREATE TABLE actors (id TEXT UNIQUE, hash INTEG
ACTOR counters(mykey);
INSERT INTO actors VALUES ('mykey',{{hash(mykey)}},

20. q().