Mercurial > projects > dwt-addons

comparison dwtx/jface/text/rules/RuleBasedScanner.d @ 129:eb30df5ca28b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Added JFace Text sources
author Frank Benoit <benoit@tionex.de>
date Sat, 23 Aug 2008 19:10:48 +0200
parents
children c4fb132a086c
comparison
equal deleted inserted replaced
128:8df1d4193877 129:eb30df5ca28b
1 /*******************************************************************************
2 * Copyright (c) 2000, 2008 IBM Corporation and others.
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 * IBM Corporation - initial API and implementation
10 * Port to the D programming language:
11 * Frank Benoit <benoit@tionex.de>
12 *******************************************************************************/
13
14 module dwtx.jface.text.rules.RuleBasedScanner;
15
16 import dwt.dwthelper.utils;
17
18
19
20 import dwtx.core.runtime.Assert;
21 import dwtx.jface.text.BadLocationException;
22 import dwtx.jface.text.IDocument;
23
24
25 /**
26 * A generic scanner which can be "programmed" with a sequence of rules.
27 * The scanner is used to get the next token by evaluating its rule in sequence until
28 * one is successful. If a rule returns a token which is undefined, the scanner will proceed to
29 * the next rule. Otherwise the token provided by the rule will be returned by
30 * the scanner. If no rule returned a defined token, this scanner returns a token
31 * which returns <code>true</code> when calling <code>isOther</code>, unless the end
32 * of the file is reached. In this case the token returns <code>true</code> when calling
33 * <code>isEOF</code>.
34 *
35 * @see IRule
36 */
37 public class RuleBasedScanner : ICharacterScanner, ITokenScanner {
38
39 /** The list of rules of this scanner */
40 protected IRule[] fRules;
41 /** The token to be returned by default if no rule fires */
42 protected IToken fDefaultReturnToken;
43 /** The document to be scanned */
44 protected IDocument fDocument;
45 /** The cached legal line delimiters of the document */
46 protected char[][] fDelimiters;
47 /** The offset of the next character to be read */
48 protected int fOffset;
49 /** The end offset of the range to be scanned */
50 protected int fRangeEnd;
51 /** The offset of the last read token */
52 protected int fTokenOffset;
53 /** The cached column of the current scanner position */
54 protected int fColumn;
55 /** Internal setting for the un-initialized column cache. */
56 protected static final int UNDEFINED= -1;
57
58 /**
59 * Creates a new rule based scanner which does not have any rule.
60 */
61 public RuleBasedScanner() {
62 }
63
64 /**
65 * Configures the scanner with the given sequence of rules.
66 *
67 * @param rules the sequence of rules controlling this scanner
68 */
69 public void setRules(IRule[] rules) {
70 if (rules !is null) {
71 fRules= new IRule[rules.length];
72 System.arraycopy(rules, 0, fRules, 0, rules.length);
73 } else
74 fRules= null;
75 }
76
77 /**
78 * Configures the scanner's default return token. This is the token
79 * which is returned when none of the rules fired and EOF has not been
80 * reached.
81 *
82 * @param defaultReturnToken the default return token
83 * @since 2.0
84 */
85 public void setDefaultReturnToken(IToken defaultReturnToken) {
86 Assert.isNotNull(defaultReturnToken.getData());
87 fDefaultReturnToken= defaultReturnToken;
88 }
89
90 /*
91 * @see ITokenScanner#setRange(IDocument, int, int)
92 */
93 public void setRange(final IDocument document, int offset, int length) {
94 Assert.isLegal(document !is null);
95 final int documentLength= document.getLength();
96 checkRange(offset, length, documentLength);
97
98 fDocument= document;
99 fOffset= offset;
100 fColumn= UNDEFINED;
101 fRangeEnd= offset + length;
102
103 String[] delimiters= fDocument.getLegalLineDelimiters();
104 fDelimiters= new char[delimiters.length][];
105 for (int i= 0; i < delimiters.length; i++)
106 fDelimiters[i]= delimiters[i].toCharArray();
107
108 if (fDefaultReturnToken is null)
109 fDefaultReturnToken= new Token(null);
110 }
111
112 /**
113 * Checks that the given range is valid.
114 * See https://bugs.eclipse.org/bugs/show_bug.cgi?id=69292
115 *
116 * @param offset the offset of the document range to scan
117 * @param length the length of the document range to scan
118 * @param documentLength the document's length
119 * @since 3.3
120 */
121 private void checkRange(int offset, int length, int documentLength) {
122 Assert.isLegal(offset > -1);
123 Assert.isLegal(length > -1);
124 Assert.isLegal(offset + length <= documentLength);
125 }
126
127 /*
128 * @see ITokenScanner#getTokenOffset()
129 */
130 public int getTokenOffset() {
131 return fTokenOffset;
132 }
133
134 /*
135 * @see ITokenScanner#getTokenLength()
136 */
137 public int getTokenLength() {
138 if (fOffset < fRangeEnd)
139 return fOffset - getTokenOffset();
140 return fRangeEnd - getTokenOffset();
141 }
142
143
144 /*
145 * @see ICharacterScanner#getColumn()
146 */
147 public int getColumn() {
148 if (fColumn is UNDEFINED) {
149 try {
150 int line= fDocument.getLineOfOffset(fOffset);
151 int start= fDocument.getLineOffset(line);
152
153 fColumn= fOffset - start;
154
155 } catch (BadLocationException ex) {
156 }
157 }
158 return fColumn;
159 }
160
161 /*
162 * @see ICharacterScanner#getLegalLineDelimiters()
163 */
164 public char[][] getLegalLineDelimiters() {
165 return fDelimiters;
166 }
167
168 /*
169 * @see ITokenScanner#nextToken()
170 */
171 public IToken nextToken() {
172
173 fTokenOffset= fOffset;
174 fColumn= UNDEFINED;
175
176 if (fRules !is null) {
177 for (int i= 0; i < fRules.length; i++) {
178 IToken token= (fRules[i].evaluate(this));
179 if (!token.isUndefined())
180 return token;
181 }
182 }
183
184 if (read() is EOF)
185 return Token.EOF;
186 return fDefaultReturnToken;
187 }
188
189 /*
190 * @see ICharacterScanner#read()
191 */
192 public int read() {
193
194 try {
195
196 if (fOffset < fRangeEnd) {
197 try {
198 return fDocument.getChar(fOffset);
199 } catch (BadLocationException e) {
200 }
201 }
202
203 return EOF;
204
205 } finally {
206 ++ fOffset;
207 fColumn= UNDEFINED;
208 }
209 }
210
211 /*
212 * @see ICharacterScanner#unread()
213 */
214 public void unread() {
215 --fOffset;
216 fColumn= UNDEFINED;
217 }
218 }
219
220