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    using ConditionalAttribute = System.Diagnostics.ConditionalAttribute;
35    using Regex = System.Text.RegularExpressions.Regex;
36    using RegexOptions = System.Text.RegularExpressions.RegexOptions;
37
38    /** <summary>
39     *  A parser for a stream of tree nodes.  "tree grammars" result in a subclass
40     *  of this.  All the error reporting and recovery is shared with Parser via
41     *  the BaseRecognizer superclass.
42     *  </summary>
43    */
44    public class TreeParser : BaseRecognizer {
45        public const int DOWN = TokenTypes.Down;
46        public const int UP = TokenTypes.Up;
47
48        // precompiled regex used by inContext
49        static string dotdot = ".*[^.]\\.\\.[^.].*";
50        static string doubleEtc = ".*\\.\\.\\.\\s+\\.\\.\\..*";
51        static Regex dotdotPattern = new Regex(dotdot, RegexOptions.Compiled);
52        static Regex doubleEtcPattern = new Regex(doubleEtc, RegexOptions.Compiled);
53
54        protected ITreeNodeStream input;
55
56        public TreeParser(ITreeNodeStream input)
57            : base() // highlight that we go to super to set state object
58        {
59            SetTreeNodeStream(input);
60        }
61
62        public TreeParser(ITreeNodeStream input, RecognizerSharedState state)
63            : base(state) // share the state object with another parser
64        {
65            SetTreeNodeStream(input);
66        }
67
68        public override void Reset() {
69            base.Reset(); // reset all recognizer state variables
70            if (input != null) {
71                input.Seek(0); // rewind the input
72            }
73        }
74
75        /** <summary>Set the input stream</summary> */
76        public virtual void SetTreeNodeStream(ITreeNodeStream input) {
77            this.input = input;
78        }
79
80        public virtual ITreeNodeStream GetTreeNodeStream() {
81            return input;
82        }
83
84        public override string SourceName {
85            get {
86                return input.SourceName;
87            }
88        }
89
90        protected override object GetCurrentInputSymbol(IIntStream input) {
91            return ((ITreeNodeStream)input).LT(1);
92        }
93
94        protected override object GetMissingSymbol(IIntStream input,
95                                          RecognitionException e,
96                                          int expectedTokenType,
97                                          BitSet follow) {
98            string tokenText =
99                "<missing " + TokenNames[expectedTokenType] + ">";
100            ITreeAdaptor adaptor = ((ITreeNodeStream)e.Input).TreeAdaptor;
101            return adaptor.Create(new CommonToken(expectedTokenType, tokenText));
102        }
103
104        /** <summary>
105         *  Match '.' in tree parser has special meaning.  Skip node or
106         *  entire tree if node has children.  If children, scan until
107         *  corresponding UP node.
108         *  </summary>
109         */
110        public override void MatchAny(IIntStream ignore) {
111            state.errorRecovery = false;
112            state.failed = false;
113            // always consume the current node
114            input.Consume();
115            // if the next node is DOWN, then the current node is a subtree:
116            // skip to corresponding UP. must count nesting level to get right UP
117            int look = input.LA(1);
118            if (look == DOWN) {
119                input.Consume();
120                int level = 1;
121                while (level > 0) {
122                    switch (input.LA(1)) {
123                        case DOWN:
124                            level++;
125                            break;
126                        case UP:
127                            level--;
128                            break;
129                        case TokenTypes.EndOfFile:
130                            return;
131                        default:
132                            break;
133                    }
134                    input.Consume();
135                }
136            }
137        }
138
139        /** <summary>
140         *  We have DOWN/UP nodes in the stream that have no line info; override.
141         *  plus we want to alter the exception type.  Don't try to recover
142         *  from tree parser errors inline...
143         *  </summary>
144         */
145        protected override object RecoverFromMismatchedToken(IIntStream input, int ttype, BitSet follow) {
146            throw new MismatchedTreeNodeException(ttype, (ITreeNodeStream)input);
147        }
148
149        /** <summary>
150         *  Prefix error message with the grammar name because message is
151         *  always intended for the programmer because the parser built
152         *  the input tree not the user.
153         *  </summary>
154         */
155        public override string GetErrorHeader(RecognitionException e) {
156            return GrammarFileName + ": node from " +
157                   (e.ApproximateLineInfo ? "after " : "") + "line " + e.Line + ":" + e.CharPositionInLine;
158        }
159
160        /** <summary>
161         *  Tree parsers parse nodes they usually have a token object as
162         *  payload. Set the exception token and do the default behavior.
163         *  </summary>
164         */
165        public override string GetErrorMessage(RecognitionException e, string[] tokenNames) {
166            if (this is TreeParser) {
167                ITreeAdaptor adaptor = ((ITreeNodeStream)e.Input).TreeAdaptor;
168                e.Token = adaptor.GetToken(e.Node);
169                if (e.Token == null) { // could be an UP/DOWN node
170                    e.Token = new CommonToken(adaptor.GetType(e.Node),
171                                              adaptor.GetText(e.Node));
172                }
173            }
174            return base.GetErrorMessage(e, tokenNames);
175        }
176
177        [Conditional("ANTLR_TRACE")]
178        public virtual void TraceIn(string ruleName, int ruleIndex) {
179            base.TraceIn(ruleName, ruleIndex, input.LT(1));
180        }
181
182        [Conditional("ANTLR_TRACE")]
183        public virtual void TraceOut(string ruleName, int ruleIndex) {
184            base.TraceOut(ruleName, ruleIndex, input.LT(1));
185        }
186
187    }
188}
189