+ public static String string(Tree<String> tree) {
+ String ret = "";
+ if (tree.head()!=null) ret += tree.head();
+ ret += string(tree.children());
+ return ret;
+ }
+ public static String string(Iterable<Tree<String>> children) {
+ String ret = "";
+ for(Tree<String> t : children) ret += string(t);
+ return ret;
+ }