One of the stranger bits of syntax I see in Elixir is for Atoms.

To quote the previous link “Atoms are constants whose values are their own name”.

What does this mean ?

Well imagine you were writing code such as

configuarion = "configuration"
ok = "ok"

Essentially the value is the same as the name, so basically instead if assigning a value of the same name we simply prefix the name with : to get the following

:configuration
:ok

In fact :true, :false and :nil are atoms but we would tend to use the alias of these, i.e. without the colon, true, false and nil.

The syntax for atoms is that they start with an alpha or underscore, can contain alphanumeric characters, can also contain @ and can end with and alphanumeric character or either ? or !. If you wish to create an atom with violates this syntax you can simply enclose in double quotes, i.e.

:"123atom"

and to prove it we can use

is_atom(:"123atom")

Atoms can also be declared starting with an uppercase alpha character such as

Atom
is_atom(Atom)

Atoms with the same content are always equivalent.

Modules are represented as atoms, for example :math is the module math and :”Elixir.String” is the same as a String.