Hmm, what's a stack machine AST? I can't follow your description of the transform, what does "remove" mean here? I can remove all of the internal nodes of a tree, which leaves me with a soup of leaf nodes, but how is that an AST for a stack machine?
Hope that clears it up.
(Add (LoadConst 1) (LoadVar x))
[PushConst 1, PushVar x, Add]
enum Expr:
case Add(left: Expr, right: Expr)
case Lit(val: Double)
enum Expr:
case Add
case Lit(val: Double)
The transformation in the other direction is not purely syntactic as you have to know that, e.g., Add gets two parameters from the stack and add those parameters back in.
class Add : Node {
Node left;
Node right;
int interpret() {
int l = left.interpret();
int r = right.interpret();
return l + r;
}
}
class Add : Node {
Node left;
Node right;
void compile(bc: ByteCode) {
left.compile(bc);
right.compile(bc);
bc.push(OP_ADD);
}
}