Loose Polymorph

Loose Polymorph

Loose polymorphs are a type of polymorph that are prefixed with $~ instead of $.

$~T
$~IndexType

Loose polymorphs will match to the first compatible type, but are also flexible to allow for potential conversion between primitive types. Loose polymorphs will match if the original $T and new $T are both integers or both floats.

record <$T> Single (value $T)

func sum(a, b <$~T> Single) <$T> Single {
    return Single(a.value + b.value)
}

For example, the above function can be called as sum(Single(10uz), Single(13si)) or sum(Single('A'ub), Single(3)). The first type match will be $T/$~T, so sum(Single(10uz), Single(13si)) would return a <usize> Single and sum(Single('A'ub), Single(3)) would return a <ubyte> Single.

Loose polymorph matching via $~T is not allowed between integers and floats. So calling it as sum(Single('A'ub), Single(3.0f)) would not resolve to the above function.