1 /*
2 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.incubator.code.parser.impl;
27
28 import jdk.incubator.code.parser.impl.Position.LineMap;
29 import jdk.incubator.code.parser.impl.Tokens.Token;
30 import java.util.Arrays;
31
32 /**
33 * The lexical analyzer maps an input stream consisting of ASCII
34 * characters and Unicode escapes into a token sequence.
35 *
36 * <p><b>This is NOT part of any supported API.
37 * If you write code that depends on this, you do so at your own risk.
38 * This code and its internal interfaces are subject to change or
39 * deletion without notice.</b>
40 */
41 public sealed interface Lexer permits Scanner {
42
43 /**
44 * Consume the next token.
45 */
46 void nextToken();
47
48 /**
49 * Return current token.
50 */
51 Tokens.Token token();
52
53 /**
54 * Return token with given lookahead.
55 */
56 Tokens.Token token(int lookahead);
57
58 /**
59 * Return the last character position of the previous token.
60 */
61 Tokens.Token prevToken();
62
63 /**
64 * Return the position where a lexical error occurred;
65 */
66 int errPos();
67
68 /**
69 * Set the position where a lexical error occurred;
70 */
71 void errPos(int pos);
72
73 /**
74 * Build a map for translating between line numbers and
75 * positions in the input.
76 *
77 * @return a LineMap
78 */
79 LineMap getLineMap();
80
81 default boolean is(Tokens.TokenKind tk) {
82 Tokens.Token t = token();
83 if (t.kind == tk) {
84 return true;
85 }
86 return false;
87 }
88
89 default Tokens.Token accept(Tokens.TokenKind tk) {
90 Tokens.Token t = token();
91 if (t.kind == tk) {
92 nextToken();
93 return t;
94 } else {
95 // @@@ Exception
96 LineMap lineMap = getLineMap();
97 int lineNumber = lineMap.getLineNumber(t.pos);
98 int columnNumber = lineMap.getColumnNumber(t.pos);
99 throw new IllegalArgumentException("Expected " + tk + " but observed " + t.kind +
100 " " + lineNumber + ":" + columnNumber);
101 }
102 }
103
104 default Tokens.Token accept(Tokens.TokenKind... tks) {
105 Token t = token();
106 for (Tokens.TokenKind tk : tks) {
107 if (acceptIf(tk)) {
108 return t;
109 }
110 }
111 // @@@ Exception
112 LineMap lineMap = getLineMap();
113 int lineNumber = lineMap.getLineNumber(t.pos);
114 int columnNumber = lineMap.getColumnNumber(t.pos);
115 throw new IllegalArgumentException("Expected one of " + Arrays.toString(tks) + " but observed " + t.kind +
116 " " + lineNumber + ":" + columnNumber);
117 }
118
119 default boolean acceptIf(Tokens.TokenKind tk) {
120 Tokens.Token t = token();
121 if (t.kind == tk) {
122 nextToken();
123 return true;
124 }
125 return false;
126 }
127
128 default RuntimeException unexpected() {
129 Tokens.Token t = token();
130 LineMap lineMap = getLineMap();
131 int lineNumber = lineMap.getLineNumber(t.pos);
132 int columnNumber = lineMap.getColumnNumber(t.pos);
133 return new IllegalArgumentException("Unexpected token " + t.kind +
134 " " + lineNumber + ":" + columnNumber);
135 }
136 }