# Subroutine Signatures

## Func

``````some_func(x: T, y: U) -> V
some_func: (T, U) -> V
``````

## Proc

``````some_proc!(x: T, y: U) => V
some_proc!: (T, U) => V
``````

## Func Method

The method type cannot be specified externally with `Self`.

``````.some_method(self, x: T, y: U) => ()
# Self.(T, U) => () takes ownership of self
.some_method: (Ref(Self), T, U) => ()
``````

## Proc Method (dependent)

In the following, assume that the type `T!` takes the type argument `N: Nat`. To specify it externally, use a type variable.

``````K!: Nat -> Type
# ~> indicates the state of the type argument before and after application (in this case, self must be a variable reference)
K!(N).some_method!: (Ref!(K! N ~> N+X), X: Nat) => ()
``````

As a note, the type of `.some_method` is `|N, X: Nat| (Ref!(K! N ~> N+X), {X}) => ()`. For methods that do not have `ref!`, i.e., are deprived of ownership after application, the type argument transition (`~>`) cannot be used.

If ownership is taken, it is as follows.

``````# If you don't use N, you can omit it with _.
# .some_method!: |N, X: Nat| (T!(N), {X}) => T!(N+X)
.some_method!|N, X: Nat|(self: T!(N), X: Nat) => T!(N+X)
``````

## Operator

It can be defined as a normal function by enclosing it with ``.

Neuter alphabetic operators such as `and` and `or` can be defined as neuter operators by enclosing them with ``.

``````and(x, y, z) = x and y and z
`_+_`(x: Foo, y: Foo) = x.a + y.a
`-_`(x: Foo) = Foo.new(-x.a)
``````