/** replaces all instances (by ==) of node with node1. Doesn't affect the node t itself */
public static void replaceNode(Tree node, Tree node1, Tree t) {
if (t.isLeaf()) return;
Tree[] kids = t.children();
List<Tree> newKids = new ArrayList<Tree>(kids.length);
for (int i = 0, n = kids.length; i < n; i++) {
if (kids[i] != node) {
newKids.add(kids[i]);
replaceNode(node, node1, kids[i]);
} else {
newKids.add(node1);
}
}
t.setChildren(newKids);
}
