Scope

Global scope

The global scope is a declarative space where the declarations' order is not important. This is the only scope in which you can declare enums, objects and protocols.

object B {
    | Here `A` is referred to before its declaration
    A a,
}

object A {
    str value,
}

| Only a constant value is allowed here
str globalValue = "hello";

Local scope

Any variable declared inside a block is local to it. Shadowing a variable from an upper scope is not allowed.

str bye = "bye";
while (condition) {
    str hello = "hello"; | Local to this block
    int bye = 12;       | -> Not allowed
}

| hello doesn't exist anymore

Upvalues

If a reference to a variable from a upper scope is made inside a function's body, the function will carry a reference to it even when the variable goes out of scope. This is an upvalue.

fun getFn() > Function () > void {
    str upvalue = "up there";

    Function () > void hello = fun () -> print(upvalue);

    return hello;
}

| `upvalue` is out of scope but still exists as an upvalue of `hello`
getFn()();