Created
January 4, 2012 17:13
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ANTLRのtree grammarでΣ演算
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grammar Calculator; | |
options { | |
output = AST; | |
ASTLabelType=CommonTree; | |
} | |
tokens { SUM; NEG; VARIABLE; } | |
@members { CommonTree subExpr; } | |
prog: sumExpr | |
; | |
sumExpr | |
: 'sum' 'i' ':' INT '..' INT 'of' expr -> ^(SUM INT INT expr) | |
; | |
finally { subExpr = $sumExpr.tree; } | |
expr: multExpr (('+'^ |'-'^) multExpr)* | |
; | |
multExpr : unary (('*'^ |'/'^) unary)* | |
; | |
unary : factor | |
| '+' factor -> factor | |
| '-' factor -> ^(NEG factor) | |
; | |
factor : DOUBLE | |
| INT | |
| 'i' -> VARIABLE | |
| '('! expr ')'! | |
; | |
INT : '0'..'9'+ ; | |
DOUBLE : INT '.' INT* | |
| '.' INT | |
; | |
COMMENT | |
: '//' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;} | |
| '/*' ( options {greedy=false;} : . )* '*/' {$channel=HIDDEN;} | |
; | |
WS : (' '|'\t'|'\n'|'\r')+ {$channel=HIDDEN;} ; |
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tree grammar Eval; | |
options { | |
tokenVocab=Calculator; | |
ASTLabelType=CommonTree; | |
} | |
@members { | |
int variable; | |
CommonTree subExpr; | |
public Eval(CommonTreeNodeStream input,CommonTree tree) { | |
this(input); | |
this.subExpr = tree; | |
} | |
private Eval(CommonTree tree, int variable){ | |
this(new CommonTreeNodeStream(tree),tree); | |
this.variable = variable; | |
} | |
} | |
prog: sumExpr { System.out.println($sumExpr.value); } | |
; | |
sumExpr returns [double value] | |
: ^(SUM | |
init=INT { int initialize = Integer.parseInt($init.text); } | |
max=INT | |
{ | |
int maximum = Integer.parseInt($max.text); | |
variable = initialize; | |
} | |
c=expr | |
{ | |
$value += c; | |
for(int i = variable + 1; i <= maximum; ++i) { | |
Eval eval = new Eval((CommonTree)subExpr.getChild(2),i); | |
value += eval.expr(); | |
} | |
} | |
) | |
; | |
expr returns [double value] | |
: ^('+' left=expr right=expr) {$value = left + right;} | |
| ^('-' left=expr right=expr) {$value = left - right;} | |
| ^('*' left=expr right=expr) {$value = left * right;} | |
| ^('/' left=expr right=expr) {$value = left / right;} | |
| ^(NEG result=expr) {$value = -result;} | |
| VARIABLE {$value = variable;} | |
| INT {$value = Integer.parseInt($INT.text);} | |
| DOUBLE {$value = Double.parseDouble($DOUBLE.text);} | |
; |
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