!7

cmodule TopDownParsing > DynSCP {
  switchable S input = "Bob paid for Charlie 's college education";
  TryPatterns root;
  transient S selectedGrouped;
  transient ReliableSingleThread rstProcessInput = dm_rstWithPreDelay(this, 500, r processInput);

  // Tree has 2 types of nodes: composite and options
  abstract class Base {
    L<Base> children;
    L<Base> children() { ret children; }
    
    abstract S grouped();
  }
  
  // composite node
  class AppliedPattern > Base {
    S pattern;
    LS arguments;
    
    L<Base> children() {
      if (children == null)
        children = map(arguments, a -> new TryPatterns(a));
      ret children;
    }

    toString { ret stdToStringWithFields(this, 'pattern, 'arguments); }
    
    S grouped() {
      ret format3_round(pattern, toStringArray(arguments));
    }
  }
  
  // options node (try different patterns)
  class TryPatterns > Base {
    S input;
    
    *() {}
    *(S *input) {}
    
    L<Base> children() {
      if (children == null) {
        children = new L;
        for (S pat : patterns())
          for (LS arguments : matchesToStringLists(flexMatchIC_all(pat, input)))
            children.add(setAll(new AppliedPattern, pattern := pat, +arguments));
      }
      ret children;
    }

    toString { ret stdToStringWithFields(this, 'input) + ", n=" + l(children()); }
    
    S grouped() {
      ret empty(children()) ? null : first(children).grouped();
    }
  }
  
  start {
    dm_watchFieldAndNow input(rstProcessInput);
  }
  
  JComponent visualize2() {
    JTree tree = jDynamicTree(root, x -> x.children());
    onTreeSelectionChanged(tree, r {
      Base base = cast jtree_selectedUserObject(tree);
      setField(selectedGrouped := base == null ? null : base.grouped());
    });
    ret northCenterAndSouthWithMargins(
      jCenteredSection("Input", dm_centeredTextField input()),
      tree,
      jCenteredSection("Grouped", dm_label selectedGrouped()));
  }
  
  LS patterns() { ret dm_getUnclearList("patterns"); }
  
  // API
  
  void processInput {
    setField(root := parse(input));
    revisualize2();
  }
  
  TryPatterns parse(S s) {
    ret new TryPatterns(s);
  }
  
  TryPatterns root() { ret root; }
}