[antlr-interest] Rephrasing message 7267 ( Where is the error?)

[rmsanjivp <rmsanjivp at yahoo.com>]

the grammar is actually


topLevel : expr;

expr : mult_expr ( (PLUS | MINUS) mult_expr)*;

mult_expr : pow_expr ((MULT | DIV) pow_expr)*;

pow_expr: primary_expr ( POWER pow_expr)?;

primary_expr: ID | (LPAREN expr RPAREN) | NUM
;

THe problem is that in the method for pow_expr because I made it 
right associative I have RPAREN as a valid lookahead after the match 
of ID. THis should not be the case as only an operator can follow 
ID. Can anyone please tell me why this is happening? If my grammar 
is wrong then where it is wrong?


I think the problem is coming because of rule (LPAREN expr RPAREN) 
because if I have this as (LPAREN ID RPAREN) then RPAREN is not 
coming as a valid token after pow_expr(). 

Kindly help me soon.

Thanks,
Sanjiv


 

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