1 /*
2  * [The "BSD license"]
3  *  Copyright (c) 2012 Terence Parr
4  *  Copyright (c) 2012 Sam Harwell
5  *  All rights reserved.
6  *
7  *  Redistribution and use in source and binary forms, with or without
8  *  modification, are permitted provided that the following conditions
9  *  are met:
10  *
11  *  1. Redistributions of source code must retain the above copyright
12  *     notice, this list of conditions and the following disclaimer.
13  *  2. Redistributions in binary form must reproduce the above copyright
14  *     notice, this list of conditions and the following disclaimer in the
15  *     documentation and/or other materials provided with the distribution.
16  *  3. The name of the author may not be used to endorse or promote products
17  *     derived from this software without specific prior written permission.
18  *
19  *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 module antlr.v4.runtime.TokenStream;
32 
33 import antlr.v4.runtime.IntStream;
34 import antlr.v4.runtime.Token;
35 import antlr.v4.runtime.TokenSource;
36 import antlr.v4.runtime.RuleContext;
37 import antlr.v4.runtime.misc.Interval;
38 
39 /**
40  * TODO add interface description
41  */
42 interface TokenStream : IntStream
43 {
44 
45     /**
46      * Get the {@link Token} instance associated with the value returned by
47      * {@link #LA LA(k)}. This method has the same pre- and post-conditions as
48      * {@link IntStream#LA}. In addition, when the preconditions of this method
49      * are met, the return value is non-null and the value of
50      * {@code LT(k).getType()==LA(k)}.
51      *
52      *  @see IntStream#LA
53      */
54     public Token LT(int k);
55 
56     /**
57      * Gets the {@link Token} at the specified {@code index} in the stream. When
58      * the preconditions of this method are met, the return value is non-null.
59      *
60      * <p>The preconditions for this method are the same as the preconditions of
61      * {@link IntStream#seek}. If the behavior of {@code seek(index)} is
62      * unspecified for the current state and given {@code index}, then the
63      * behavior of this method is also unspecified.</p>
64      *
65      * <p>The symbol referred to by {@code index} differs from {@code seek()} only
66      * in the case of filtering streams where {@code index} lies before the end
67      * of the stream. Unlike {@code seek()}, this method does not adjust
68      * {@code index} to point to a non-ignored symbol.</p>
69      *
70      *  @throws IllegalArgumentException if {code index} is less than 0
71      *  @throws UnsupportedOperationException if the stream does not support
72      *  retrieving the token at the specified index
73      */
74     public Token get(int index);
75 
76     /**
77      * Gets the underlying {@link TokenSource} which provides tokens for this
78      * stream.
79      */
80     public TokenSource getTokenSource();
81 
82     /**
83      * Return the text of all tokens within the specified {@code interval}. This
84      * method behaves like the following code (including potential exceptions
85      * for violating preconditions of {@link #get}, but may be optimized by the
86      * specific implementation.
87      *
88      * <pre>
89      * TokenStream stream = ...;
90      * String text = "";
91      * for (int i = interval.a; i &lt;= interval.b; i++) {
92      *   text += stream.get(i).getText();
93      * }
94      * </pre>
95      *
96      *  @param interval The interval of tokens within this stream to get text
97      * for.
98      *  @return The text of all tokens within the specified interval in this
99      * stream.
100      *
101      *  @throws NullPointerException if {@code interval} is {@code null}
102      */
103     public string getText(Interval interval);
104 
105     /**
106      * Return the text of all tokens in the stream. This method behaves like the
107      * following code, including potential exceptions from the calls to
108      * {@link IntStream#size} and {@link #getText(Interval)}, but may be
109      * optimized by the specific implementation.
110      *
111      * <pre>
112      * TokenStream stream = ...;
113      * String text = stream.getText(new Interval(0, stream.size()));
114      * </pre>
115      *
116      *  @return The text of all tokens in the stream.
117      */
118     public string getText();
119 
120     /**
121      * Return the text of all tokens in the source interval of the specified
122      * context. This method behaves like the following code, including potential
123      * exceptions from the call to {@link #getText(Interval)}, but may be
124      * optimized by the specific implementation.
125      *
126      * <p>If {@code ctx.getSourceInterval()} does not return a valid interval of
127      * tokens provided by this stream, the behavior is unspecified.</p>
128      *
129      * <pre>
130      * TokenStream stream = ...;
131      * String text = stream.getText(ctx.getSourceInterval());
132      * </pre>
133      *
134      *  @param ctx The context providing the source interval of tokens to get
135      *  text for.
136      *  @return The text of all tokens within the source interval of {@code ctx}.
137      */
138     public string getText(RuleContext ctx);
139 
140     /**
141      * Return the text of all tokens in this stream between {@code start} and
142      * {@code stop} (inclusive).
143      *
144      * <p>If the specified {@code start} or {@code stop} token was not provided by
145      * this stream, or if the {@code stop} occurred before the {@code start}
146      * token, the behavior is unspecified.</p>
147      *
148      * <p>For streams which ensure that the {@link Token#getTokenIndex} method is
149      * accurate for all of its provided tokens, this method behaves like the
150      * following code. Other streams may implement this method in other ways
151      * provided the behavior is consistent with this at a high level.</p>
152      *
153      * <pre>
154      * TokenStream stream = ...;
155      * String text = "";
156      * for (int i = start.getTokenIndex(); i &lt;= stop.getTokenIndex(); i++) {
157      *   text += stream.get(i).getText();
158      * }
159      * </pre>
160      *
161      *  @param start The first token in the interval to get text for.
162      *  @param stop The last token in the interval to get text for (inclusive).
163      *  @return The text of all tokens lying between the specified {@code start}
164      *  and {@code stop} tokens.
165      *
166      *  @throws UnsupportedOperationException if this stream does not support
167      *  this method for the specified tokens
168      */
169     public string getText(Token start, Token stop);
170 
171 }