| CARVIEW |
Practical functional programming
for a parallel world
fact(0) -> 1; %% Pattern matching for control-flow
fact(N) -> N * fact(N-1). %% Recursion to create loops
> example:fact(10). %% Interactive shell for fast iterations
3628800
> [{I, example:fact(I)} || I <- lists:seq(1,10)].
[{1, 1}, {2, 2}, {3, 6}, {4, 24}, {5, 120}, {6, 720},
{7, 5040}, {8, 40320}, {9, 362880}, {10, 3628800}]
Functional programming
> Fruits = ["banana","monkey","jungle"]. %% Immutable variables
["banana","monkey","jungle"]
> lists:map(fun string:uppercase/1, Fruits). %% Map values using stdlib functions
["BANANA","MONKEY","JUNGLE"]
%% Fold over lists using custom functions
> lists:foldl(fun(Str, Cnt) -> string:length(Str) + Cnt end, 0, Fruits).
18
Higher-order functions
> Parent = self(). %% Get own process id
<0.376.0>
> Child = spawn(fun() -> receive go -> Parent ! lists:seq(1,100) end end).
<0.930.0>
> Child ! go. %% Send message to child
go
> receive Reply -> Reply end. %% Receive response from child
[1,2,3,4,5,6,7,8,9,10,11|...]
Lightweight processes
-spec even(list(integer())) -> list(integer()).
even(Numbers) ->
mapreduce(Numbers, fun(Number) -> Number rem 2 == 0 end).
mapreduce(Numbers, Function) ->
Parent = self(),
[spawn(fun() -> Parent ! {Number, Function(Number)} end) || Number <- Numbers],
lists:flatten(
[receive {Number, true} -> Number; _ -> [] end || Number <- Numbers]).
Parallel map-reduce to find even numbers
%% Return factorial for N
fact(0) -> 1;
fact(N) -> N * fact(N-1).
> example:fact(10).
3628800
Functional programming
> Fruits = ["banana","monkey"].
["banana","monkey"]
> lists:map(
fun string:uppercase/1,
Fruits).
["BANANA","MONKEY"]
Higher-order functions
> Me = self().
<0.376.0> %% Send msg using !
> spawn(fun() -> Me!lists:seq(1,10) end).
<0.930.0>
> receive Reply -> Reply end.
[1,2,3,4,5,6,7,8,9,10]
Light-weight processes
-spec even(In) -> Out
when In :: list(integer()),
Out :: list(integer()).
even(Numbers) ->
[Number || Number <- Numbers,
Number rem 2 == 0].
Find even numbers
What is Erlang?
Erlang is a programming language used to build massively scalable soft real-time systems with requirements on high availability. Some of its uses are in telecoms, banking, e-commerce, computer telephony and instant messaging. Erlang's runtime system has built-in support for concurrency, distribution and fault tolerance.
Erlang QuickstartWhat is OTP?
OTP is set of Erlang libraries and design principles providing middle-ware to develop these systems. It includes its own distributed database, applications to interface towards other languages, debugging and release handling tools.
Getting Started with OTPNews
-
Erlang/OTP 28.3 Release
December 10, 2025 by Henrik Nord - Erlang/OTP 28.3 is the second maintenance patch package for OTP 28, with mostly bug fixes.
-
Erlang/OTP 28.1 Release
September 17, 2025 by Henrik Nord - Erlang/OTP 28.1 is the first maintenance patch package for OTP 28, with mostly bug fixes.
-
Erlang/OTP 28.0
May 21, 2025 by Henrik Nord - Erlang/OTP 28.0 is a new major release with new features, improvements as well as a few incompatibilities.
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