yacc - Bison: Give left precedence to a rule? -

with bison have many %left's (+,*, etc) , few %right's (=, +=, etc). these tokens. have rule. its

| rval | attrdata rval 

the problem is, attrdata rval returns rval attrdata 1+1 either (attrdata 1) +1 or attrdata (1+1). apply left rule attrdata doesnt work cause isnt token. tried %prec , error too.

i can fix writing | attrdata '(' rval ')' dont want , rather have users write attrdata (1+1) since of time they'll mean (attrdata 1)+1.

how give rule left precedence?

the thing similar have else, solved forcing braces no confusion (if cond { if cond } else )

you can set explicit precedences may you

if else example

%nonassoc lower_than_else  %nonassoc else  %% stmt   :    if expr stmt %prec lower_than_else ;        |    if expr stmt else stmt;