Control flow

Helios has conventional if-else branching, and also a switch expression for enum values.

However, there are no for-loops nor while-loops (looping must be through recursion instead).

If-else

Helios has conventional if-else syntax for branching:

if (tag == 0) {
  23
} else if (tag == 1) {
  42
} else {
  0
}

The last expression in each branch block is implicitly returned.

if-else can be used like any other expression:

x = if (true) {
  42
} else {
  24
}

switch

A switch expression is used to perform different actions depending on the enum variant. It is similar to a switch statement in C or Go (and dissimilar to a match expression in Rust, as Helios doesn't support pattern-matching):

enum MyEnum {
    A{...} 
    B{...}
    C{...}
}

func main(x: MyEnum) -> Bool {
	x.switch {
		a: A => { 
			... // expression must use a
		},
		B => {
			...
		},
		_ => true // default must come last if all sub-types of MyEnum aren't handled explicitely
		// braces surrounding the cases are optional
	}
}