1use crate::arena::{ExprArena, ExprId, ExprNode};
2
3pub trait Visitor {
6 fn visit(&mut self, arena: &ExprArena, id: ExprId, node: &ExprNode);
7}
8
9pub fn walk<V: Visitor>(arena: &ExprArena, id: ExprId, visitor: &mut V) {
11 let node = arena.get(id);
12 visitor.visit(arena, id, node);
13 match node {
14 ExprNode::Add(children) | ExprNode::Mul(children) => {
15 for &child in children {
16 walk(arena, child, visitor);
17 }
18 }
19 ExprNode::Neg(inner)
20 | ExprNode::Sin(inner)
21 | ExprNode::Cos(inner)
22 | ExprNode::Exp(inner)
23 | ExprNode::Log(inner)
24 | ExprNode::Abs(inner) => {
25 let inner = *inner;
26 walk(arena, inner, visitor);
27 }
28 ExprNode::Pow(base, exp) => {
29 let base = *base;
30 let exp = *exp;
31 walk(arena, base, visitor);
32 walk(arena, exp, visitor);
33 }
34 ExprNode::Div(num, den) => {
35 let num = *num;
36 let den = *den;
37 walk(arena, num, visitor);
38 walk(arena, den, visitor);
39 }
40 ExprNode::Const(_) | ExprNode::Var(_) | ExprNode::Param(_) | ExprNode::Linear { .. } => {}
41 }
42}