Methods
In MoonBit, methods are toplevel functions associated with a type.
Methods can be declared using the syntax fn T::method_name(..) -> ..,
where the method is associated with type T.
Within the signature of the method, you can use Self to refer to T,
this can simplify the syntax if T is very long.
There are two ways to invoke a method:
- methods can always be invoked with the syntax
T::method_name(..) - methods can also be invoked with the syntax
x.method_name(..), which is equivalent toT::method_name(x, ..), whereTis the type ofx
There are already a lot of methods in previous lessons, such as Array::make(..) and arr.length().
Methods support partial application as well, both x.f(_) and _.f(..) work as expected.
type MyInt Int derive(Show)
fn MyInt::increment(self : Self) -> Self {
let MyInt(x) = self
MyInt(x + 1)
}
fn main {
let x = MyInt(39)
let y = x.increment() // call method via dot syntax
let z = MyInt::increment(y) // call methods using qualified syntax
println(z)
}