struct Foo {
	value ?f64
}

fn (f Foo) bar(m map[rune]f64) f64 {
	return m[`x`] or { 0.0 } * f.value
}

fn main() {
	f := Foo{
		value: 1.0
	}
	println(f.bar(map[rune]f64{}))
}