Programming Elixir ≥ 1.6

Specifying a Type

A type is simply a subset of all possible values in a language. For example, the type integer means all the possible integer values, but excludes lists, binaries, PIDs, and so on.

The basic types in Elixir are as follows: any, atom, float, fun, integer, list, map, maybe_improper_list, none, pid, port, reference, struct, and tuple.

The type any (and its alias, _) is the set of all values, and none is the empty set.

A literal atom or integer is the set containing just that value.

The value nil can be represented as nil.

Collection Types

A list is represented as [type], where type is any of the basic or combined types. This notation does not signify a list of one element—it simply says that elements of the list will be of the ...