text: //  Copyright 2010 Todd Ditchendorf
  //
  //  Licensed under the Apache License, Version 2.0 (the "License");
  //  you may not use this file except in compliance with the License.
  //  You may obtain a copy of the License at
  //
  //  http://www.apache.org/licenses/LICENSE-2.0
  //
  //  Unless required by applicable law or agreed to in writing, software
  //  distributed under the License is distributed on an "AS IS" BASIS,
  //  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  //  See the License for the specific language governing permissions and
  //  limitations under the License.
  
  #import <Foundation/Foundation.h>
  
  @class PKRuleNode;
  @class PKTokenNode;
  @class PKToken;
  
  @interface PKParseTree : NSObject <NSCopying> {
      PKParseTree *parent;
      NSMutableArray *children;
      id userInfo;
      BOOL matched;
  }
  + (PKParseTree *)parseTree;
  
  - (PKRuleNode *)addChildRule:(NSString *)name;
  - (PKTokenNode *)addChildToken:(PKToken *)tok;
  - (void)addChild:(PKParseTree *)tr;
  
  - (NSString *)treeDescription;
  
  @property (nonatomic, assign, readonly) PKParseTree *parent;  // weak ref
  @property (nonatomic, retain, readonly) NSMutableArray *children;
  @property (nonatomic, retain) id userInfo;
  @property (nonatomic, getter=isMatched) BOOL matched;
  @end
  