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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
/*
* Copyright © 2002 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* California 95054, U.S.A. All rights reserved. Sun Microsystems, Inc. has
* intellectual property rights relating to technology embodied in the product
* that is described in this document. In particular, and without limitation,
* these intellectual property rights may include one or more of the U.S.
* patents listed at http://www.sun.com/patents and one or more additional
* patents or pending patent applications in the U.S. and in other countries.
* U.S. Government Rights - Commercial software. Government users are subject
* to the Sun Microsystems, Inc. standard license agreement and applicable
* provisions of the FAR and its supplements. Use is subject to license terms.
* Sun, Sun Microsystems, the Sun logo and Java are trademarks or registered
* trademarks of Sun Microsystems, Inc. in the U.S. and other countries. This
* product is covered and controlled by U.S. Export Control laws and may be
* subject to the export or import laws in other countries. Nuclear, missile,
* chemical biological weapons or nuclear maritime end uses or end users,
* whether direct or indirect, are strictly prohibited. Export or reexport
* to countries subject to U.S. embargo or to entities identified on U.S.
* export exclusion lists, including, but not limited to, the denied persons
* and specially designated nationals lists is strictly prohibited.
*/
options {
USER_TOKEN_MANAGER = true;
}
PARSER_BEGIN(CalcInputParser)
public class CalcInputParser {
}
PARSER_END(CalcInputParser)
void Input() :
{
double larg = 0.0;
double rarg;
}
{
(
[
larg=Number()
{
CalcGUI.print(larg);
}
]
(
<ADD>
rarg=Number()
{
larg = larg + rarg;
CalcGUI.print(larg);
}
|
<SUB>
rarg=Number()
{
larg = larg - rarg;
CalcGUI.print(larg);
}
|
<MUL>
rarg=Number()
{
larg = larg * rarg;
CalcGUI.print(larg);
}
|
<DIV>
rarg=Number()
{
larg = (rarg==0) ? Float.POSITIVE_INFINITY : (larg / rarg);
CalcGUI.print(larg);
}
)*
<EQ: "=" >
)*
}
double Number() :
{
Token t;
String image = "";
double value = 0.0;
double decimalPlace = 1.0;
}
{
(
t=<DIGIT>
{
image += t.image;
value = value*10 + Integer.parseInt(t.image);
CalcGUI.print(image);
}
)+
[
<DOT>
{
image += ".";
CalcGUI.print(image);
}
(
t=<DIGIT>
{
image += t.image;
decimalPlace *= 0.1;
value = value + Integer.parseInt(t.image)*decimalPlace;
CalcGUI.print(image);
}
)+
]
{
return value;
}
|
<DOT>
{
image = "0.";
CalcGUI.print(image);
}
(
t=<DIGIT>
{
image += t.image;
decimalPlace *= 0.1;
value = value + Integer.parseInt(t.image)*decimalPlace;
CalcGUI.print(image);
}
)+
{
return value;
}
}
|
