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
|
class LangParser extends Parser;
options {
codeGenMakeSwitchThreshold = 3;
codeGenBitsetTestThreshold = 4;
buildAST=true;
}
block
: LCURLY^ ( statement )* RCURLY!
;
statement
: expr SEMI!
| "if"^ LPAREN! expr RPAREN! statement
( "else"! statement )?
| "while"^ LPAREN! expr RPAREN! statement
|! b:block { statement_AST = b_AST; }
// do some manual tree returning
;
expr: assignExpr
;
assignExpr
: aexpr (ASSIGN^ assignExpr)?
;
aexpr
: mexpr (PLUS^ mexpr)*
;
mexpr
: atom (STAR^ atom)*
;
atom: ID
| INT
;
class LangWalker extends TreeParser;
block
: #( LCURLY ( stat )+ )
;
stat: #("if" expr stat (stat)?)
| #("while" expr stat)
| expr
| block
;
expr: #(ASSIGN expr expr) {System.out.println("found assign");}
| #(PLUS expr expr) {System.out.println("found +");}
| #(STAR expr expr) {System.out.println("found *");}
| a:ID {System.out.println("found ID "+a.getText());}
| b:INT {System.out.println("found INT "+b.getText());}
;
class LangLexer extends Lexer;
WS : (' '
| '\t'
| '\n'
| '\r')
{ _ttype = Token.SKIP; }
;
LPAREN: '('
;
RPAREN: ')'
;
LCURLY: '{'
;
RCURLY: '}'
;
STAR: '*'
;
PLUS: '+'
;
ASSIGN
: '='
;
SEMI: ';'
;
COMMA
: ','
;
protected
ESC : '\\'
( 'n'
| 'r'
| 't'
| 'b'
| 'f'
| '"'
| '\''
| '\\'
| ('0'..'3') ( DIGIT (DIGIT)? )?
| ('4'..'7') (DIGIT)?
)
;
protected
DIGIT
: '0'..'9'
;
INT : (DIGIT)+
;
ID : ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'_'|'0'..'9')*
{
Integer i = (Integer)literals.get(getText());
if ( i!=null ) {
_ttype = i.intValue();
}
}
;
|
