BasicError :: enum {
	bad
	worse
}

DetailError :: union(enum) {
	code i32
	empty void
}

Left :: enum {
	left
}

Right :: enum {
	right
}

Both :: alias Left | Right

BoxA :: union(enum) {
	a i32
}

BoxB :: union(enum) {
	b void
}

Box :: alias BoxA | BoxB

maybe :: func(value i32) i32 ! BasicError {
	if (value == 0) return .bad
	return value + 1
}

via_try :: func(value i32) i32 ! BasicError {
	unwrapped :: try maybe(value)
	return unwrapped + 1
}

with_detail :: func(value i32) i32 ! DetailError {
	if (value == 0) return DetailError{ code = 5 }
	if (value == 1) return .empty
	return value
}

pick :: func(value Both) i32 {
	match value {
		.left:  return 10
		.right: return 20
	}
}

payload :: func(value Box) i32 {
	match value {
		.a |n|: return n
		.b:     return 3
	}
}

main :: func() i32 {
	acc i32 = 0

	a :: maybe(0) catch 7
	b :: maybe(4) catch 99
	c :: via_try(3) catch 99
	d :: via_try(0) catch 11
	e :: with_detail(0) catch 13
	f :: with_detail(2) catch 99

	acc = acc + a + b + c + d + e + f
	acc = acc + pick(.left)
	r Right = .right
	acc = acc + pick(r)
	box BoxA = BoxA{ a = 8 }
	acc = acc + payload(box)
	empty BoxB = .b
	acc = acc + payload(empty)

	# 7 + 5 + 5 + 11 + 13 + 2 + 10 + 20 + 8 + 3 = 84
	return acc - 84
}