Tips for golfing in Erlang

Question

Does anybody have tips for golfing in Erlang? I'm looking for specific things that can be applied to Erlang, not any language. I know we already have tips for Elixir, but that is different.

As usual, please post separate tips in separate answers.

Answer 1

Use the ending conditions

Suppose you have a function reversing a list:

r([H|T])->[T]++r(H);r([])->[].

Since this is the only condition left, this can be golfed into:

r([H|T])->r(T)++[H];r(_)->[].

Or, since this is an identity function:

r([H|T])->r(T)++[H];r(I)->I.

You can also abuse the wild-cards in if statements. E.g.

if A<B->A;true->B end.

This can be golfed into:

if A<B->A;_->B end.

Answer 2

Use Built-in Functions (BIFs)

Erlang’s built-ins like length/1, hd/1, tl/1, and arithmetic operators (+, -, *, div, rem) are concise. Prefer them over manual implementations. For example, hd(L) is shorter than [H|_]=L,H.

Use Guards Sparingly

Guards can shorten logic, but they add characters. Only use them if they replace a longer construct. For example:

f(X)when X>0->1;f(_)->0.

is concise if it avoids a case.

String Handling

Erlang strings are lists of integers, so use [C] for single characters (e.g., $a for 97) to save space over quoted strings. For example:

f()->$a.

is shorter than:

f()->"a".