1/*
2 * [The "BSD licence"]
3 * Copyright (c) 2005-2008 Terence Parr
4 * All rights reserved.
5 *
6 * Conversion to C#:
7 * Copyright (c) 2008-2009 Sam Harwell, Pixel Mine, Inc.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33namespace Antlr.Runtime.Tree
34{
35    /** <summary>A stream of tree nodes, accessing nodes from a tree of some kind</summary> */
36    public interface ITreeNodeStream : IIntStream
37    {
38        /** <summary>
39         *  Get a tree node at an absolute index i; 0..n-1.
40         *  If you don't want to buffer up nodes, then this method makes no
41         *  sense for you.
42         *  </summary>
43         */
44        object this[int i]
45        {
46            get;
47        }
48
49        /** <summary>
50         *  Get tree node at current input pointer + i ahead where i=1 is next node.
51         *  i&lt;0 indicates nodes in the past.  So LT(-1) is previous node, but
52         *  implementations are not required to provide results for k &lt; -1.
53         *  LT(0) is undefined.  For i&gt;=n, return null.
54         *  Return null for LT(0) and any index that results in an absolute address
55         *  that is negative.
56         *  </summary>
57         *
58         *  <remarks>
59         *  This is analogus to the LT() method of the TokenStream, but this
60         *  returns a tree node instead of a token.  Makes code gen identical
61         *  for both parser and tree grammars. :)
62         *  </remarks>
63         */
64        object LT( int k );
65
66        /** <summary>
67         *  Where is this stream pulling nodes from?  This is not the name, but
68         *  the object that provides node objects.
69         *  </summary>
70         */
71        object TreeSource
72        {
73            get;
74        }
75
76        /** <summary>
77         *  If the tree associated with this stream was created from a TokenStream,
78         *  you can specify it here.  Used to do rule $text attribute in tree
79         *  parser.  Optional unless you use tree parser rule text attribute
80         *  or output=template and rewrite=true options.
81         *  </summary>
82         */
83        ITokenStream TokenStream
84        {
85            get;
86        }
87
88        /** <summary>
89         *  What adaptor can tell me how to interpret/navigate nodes and
90         *  trees.  E.g., get text of a node.
91         *  </summary>
92         */
93        ITreeAdaptor TreeAdaptor
94        {
95            get;
96        }
97
98        /** <summary>
99         *  As we flatten the tree, we use UP, DOWN nodes to represent
100         *  the tree structure.  When debugging we need unique nodes
101         *  so we have to instantiate new ones.  When doing normal tree
102         *  parsing, it's slow and a waste of memory to create unique
103         *  navigation nodes.  Default should be false;
104         *  </summary>
105         */
106        bool UniqueNavigationNodes
107        {
108            get;
109            set;
110        }
111
112        /** <summary>
113         *  Return the text of all nodes from start to stop, inclusive.
114         *  If the stream does not buffer all the nodes then it can still
115         *  walk recursively from start until stop.  You can always return
116         *  null or "" too, but users should not access $ruleLabel.text in
117         *  an action of course in that case.
118         *  </summary>
119         */
120        string ToString( object start, object stop );
121
122
123        #region REWRITING TREES (used by tree parser)
124
125        /** <summary>
126         *  Replace from start to stop child index of parent with t, which might
127         *  be a list.  Number of children may be different
128         *  after this call.  The stream is notified because it is walking the
129         *  tree and might need to know you are monkeying with the underlying
130         *  tree.  Also, it might be able to modify the node stream to avoid
131         *  restreaming for future phases.
132         *  </summary>
133         *
134         *  <remarks>
135         *  If parent is null, don't do anything; must be at root of overall tree.
136         *  Can't replace whatever points to the parent externally.  Do nothing.
137         *  </remarks>
138         */
139        void ReplaceChildren( object parent, int startChildIndex, int stopChildIndex, object t );
140
141        #endregion
142
143    }
144}
145