Type Annotation

Example in variable declaration.

Link in Ion shell online manual: https://doc.redox-os.org/ion-manual/variables/00-variables.html?highlight=type#type-checked-assignments

let a:bool = 1
let b:bool = true
let c:bool = n
echo $a $b $c
let fail:bool = ""

Example in funciont declaration

Link in Ion shell online manual: https://doc.redox-os.org/ion-manual/functions.html

fn square x:int
    echo $(( x * x ))
end

square 3
square a