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|
options {
language="Cpp";
}
class CalcParser extends Parser;
options {
genHashLines = true; // include line number information
buildAST = true; // uses CommonAST by default
}
expr
: mexpr (PLUS^ mexpr)* SEMI!
;
mexpr
: atom (STAR^ atom)*
;
atom: INT
;
class CalcLexer extends Lexer;
WS_ : (' '
| '\t'
| '\n'
| '\r')
{ _ttype = ANTLR_USE_NAMESPACE(antlr)Token::SKIP; }
;
LPAREN: '('
;
RPAREN: ')'
;
STAR: '*'
;
PLUS: '+'
;
SEMI: ';'
;
protected
DIGIT
: '0'..'9'
;
INT : (DIGIT)+
;
class CalcTreeWalker extends TreeParser;
expr returns [float r]
{
float a,b;
r=0;
}
: #(PLUS a=expr b=expr) {r = a+b;}
| #(STAR a=expr b=expr) {r = a*b;}
| i:INT {r = atof(i->getText().c_str());}
;
|
