1 | type Tree = Empty | Node |
2 | |
3 | struct Empty {} |
4 | |
5 | struct Node { |
6 | value int |
7 | left Tree |
8 | right Tree |
9 | } |
10 | |
11 | // Note: a match expression, infers the type of its result |
12 | // from the type of the return value in the first branch, |
13 | // => it needs an explicit int(0) cast here: |
14 | fn size(tree Tree) int { |
15 | return match tree { |
16 | Empty { int(0) } |
17 | Node { 1 + size(tree.left) + size(tree.right) } |
18 | } |
19 | } |
20 | |
21 | fn main() { |
22 | node1 := Node{30, Empty{}, Empty{}} |
23 | node2 := Node{20, Empty{}, Empty{}} |
24 | tree := Node{10, node1, node2} |
25 | println('tree structure:\n ${tree}') |
26 | println('tree size: ${size(tree)}') |
27 | } |