// [The "BSD licence"]
// Copyright (c) 2006-2007 Kay Roepke
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in the
//    documentation and/or other materials provided with the distribution.
// 3. The name of the author may not be used to endorse or promote products
//    derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
// IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
// NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


#import <Foundation/Foundation.h>
#import "IntStream.h"
#import "CharStream.h"
#import "TokenStream.h"
#import "CommonTree.h"
#import "CommonTreeAdaptor.h"

@protocol TreeNodeStream < IntStream > 

- (id) initWithTree:(CommonTree *)theTree;

/** Get a tree node at an absolute index i; 0..n-1.
 *  If you don't want to buffer up nodes, then this method makes no
 *  sense for you.
 */
- (id) get:(NSInteger) idx;
/** Get tree node at current input pointer + i ahead where i=1 is next node.
 *  i<0 indicates nodes in the past.  So LT(-1) is previous node, but
 *  implementations are not required to provide results for k < -1.
 *  LT(0) is undefined.  For i>=n, return null.
 *  Return null for LT(0) and any index that results in an absolute address
 *  that is negative.
 *
 *  This is analogus to the LT() method of the TokenStream, but this
 *  returns a tree node instead of a token.  Makes code gen identical
 *  for both parser and tree grammars. :)
 */
- (id) LT:(NSInteger)k;
/** Where is this stream pulling nodes from?  This is not the name, but
 *  the object that provides node objects.
 */
- (id) getTreeSource;
/** If the tree associated with this stream was created from a TokenStream,
 *  you can specify it here.  Used to do rule $text attribute in tree
 *  parser.  Optional unless you use tree parser rule text attribute
 *  or output=template and rewrite=true options.
 */
- (id<TokenStream>) getTokenStream; 
/** What adaptor can tell me how to interpret/navigate nodes and
 *  trees.  E.g., get text of a node.
 */
- (id<TreeAdaptor>) getTreeAdaptor;
/** As we flatten the tree, we use UP, DOWN nodes to represent
 *  the tree structure.  When debugging we need unique nodes
 *  so we have to instantiate new ones.  When doing normal tree
 *  parsing, it's slow and a waste of memory to create unique
 *  navigation nodes.  Default should be false;
 */
- (void) setUniqueNavigationNodes:(BOOL)flag;
/** Reset the tree node stream in such a way that it acts like
 *  a freshly constructed stream.
 */
- (void) reset;

/** Return the text of all nodes from start to stop, inclusive.
 *  If the stream does not buffer all the nodes then it can still
 *  walk recursively from start until stop.  You can always return
 *  null or "" too, but users should not access $ruleLabel.text in
 *  an action of course in that case.
 */
- (NSString *) toStringFromNode:(id)startNode ToNode:(id)stopNode;

/** Replace from start to stop child index of parent with t, which might
 *  be a list.  Number of children may be different
 *  after this call.  The stream is notified because it is walking the
 *  tree and might need to know you are monkeying with the underlying
 *  tree.  Also, it might be able to modify the node stream to avoid
 *  restreaming for future phases.
 *
 *  If parent is null, don't do anything; must be at root of overall tree.
 *  Can't replace whatever points to the parent externally.  Do nothing.
 */
- (void) replaceChildren:(id)parent From:(NSInteger)startChildIndex To:(NSInteger)stopChildIndex With:(id) t;
    

@end