1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.qpid.messaging.util;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;
/**
* Lexicon
*
*/
public class Lexicon
{
private List<Token.Type> types;
private Token.Type eof;
public Lexicon()
{
this.types = new ArrayList<Token.Type>();
this.eof = null;
}
public Token.Type define(String name, String pattern)
{
Token.Type t = new Token.Type(name, pattern);
types.add(t);
return t;
}
public Token.Type eof(String name)
{
Token.Type t = new Token.Type(name, null);
eof = t;
return t;
}
public Lexer compile()
{
StringBuilder joined = new StringBuilder();
for (Token.Type t : types)
{
if (joined.length() > 0)
{
joined.append('|');
}
joined.append('(').append(t.getPattern()).append(')');
}
Pattern rexp = Pattern.compile(joined.toString());
return new Lexer(new ArrayList<Token.Type>(types), eof, rexp);
}
public static final void main(String[] args)
{
StringBuilder input = new StringBuilder();
for (String a : args)
{
if (input.length() > 0)
{
input.append(" ");
}
input.append(a);
}
Lexicon lxi = new Lexicon();
lxi.define("FOR", "for");
lxi.define("IF", "if");
lxi.define("LPAREN", "\\(");
lxi.define("RPAREN", "\\)");
lxi.define("ID", "[\\S]+");
lxi.define("WSPACE", "[\\s]+");
lxi.eof("EOF");
Lexer lx = lxi.compile();
for (Token t : lx.lex(input.toString()))
{
System.out.println(t);
}
}
}
|
