package nuthatch.examples;

import static nuthatch.library.JoinPoints.down;
import static nuthatch.library.JoinPoints.leaf;
import static nuthatch.library.JoinPoints.up;
import nuthatch.library.BaseWalk;
import nuthatch.library.Walk;
import nuthatch.walker.impl.SimpleWalker;

public class ToString {
  public static void main(String[] args) {
      // Walk which outputs the tree in a term-like representation. The result are accumulated in the
      // stringbuffer 's'.
      final StringBuffer s = new StringBuffer();
      Walk<SimpleWalker<String, String>> toTerm = new BaseWalk<SimpleWalker<String, String>>() {
          @Override
          public int step(SimpleWalker<String, String> w) {
              if(leaf(w)) { // we're at a leaf, print data value
                  s.append(w.getData().toString());
              }
              else if(down(w)) { // first time we see this node, print constructor name
                  s.append(w.getName() + "(");
              }
              else if(up(w)) { // just finished with children, close parenthesis
                  s.append(")");
              }
              else { // coming up from a child (not the last), insert a comma
                  s.append(", ");
              }

              return NEXT;
          }
      };

      // instantiate walker with an example tree and the above step function
      SimpleWalker<String, String> toTermWalker = new SimpleWalker<String, String>(ExampleTree.TREE.makeCursor(), toTerm);
      // run it
      toTermWalker.start();
      // print the contents of S
      System.out.println(s.toString());
  }
}