Function Types
The fn(T1, T2, ...) -> R type for fields that hold callables.
The type fn(T1, T2, ...) -> R describes a callable. Use it for fields that hold callbacks.
wcl
type Step {
apply: fn(i32) -> i32
}
Lazy and cycle-checked
Function values participate in WCL's lazy field evaluation. Each call evaluates its body in a fresh context, and circular references between fields are detected and reported.