t015calc.g revision 324c4644fee44b9898524c09511bd33c3f12e2df 
1grammar t015calc;
2options {
3  language = JavaScript;
4}
5
6@parser::members {
7this.emitErrorMessage = function(msg) {
8    if (!this.reportedErrors) {
9        this.reportedErrors = [msg];
10    } else {
11        this.reportedErrors.push(msg)
12    }
13};
14}
15
16evaluate returns [result]: r=expression {result = r;};
17
18expression returns [result]: r=mult (
19    '+' r2=mult {r += r2;}
20  | '-' r2=mult {r -= r2;}
21  )* {result = r};
22
23mult returns [result]: r=log (
24    '*' r2=log {r *= r2;}
25  | '/' r2=log {r /= r2;}
26  )* {result = r};
27
28log returns [result]: 'ln' r=exp {result = Math.log(r);}
29    | r=exp {result = r;}
30    ;
31
32exp returns [result]: r=atom ('^' r2=atom {r = Math.pow(r,r2);} )? {result = r;}
33    ;
34
35atom returns [result]:
36    n=INTEGER {result = parseInt($n.text, 10);}
37  | n=DECIMAL {result = parseFloat($n.text);} 
38  | '(' r=expression {result = r;} ')'
39  | 'PI' {result = Math.PI;}
40  | 'E' {result = Math.E;}
41  ;
42
43INTEGER: DIGIT+;
44
45DECIMAL: DIGIT+ '.' DIGIT+;
46
47fragment
48DIGIT: '0'..'9';
49
50WS: (' ' | '\n' | '\t')+ {$channel = HIDDEN;};
51