Yacc and a calculator

I have been reading the lex & yacc book by Levine, Mason and Brown and have
a question on how to extend the calculator example. Suppose I wish to allow
the user to enter 8 5 and have it parsed as 8*5, how do I do that?


I have tried:


expression: ...
                | ...
                | expression expression { ... }


but that produces shift/reduce conflicts. The problem is not precedence,
but associativity, right? So how do I tell Yacc (Bison to be exact) what
the assocativity is for this expression? I tried %prec as shown in the book
using UMINUS be that only reduced the shift/reduce conflicts from something
like 16 to 8.


In case you wondering, this is not a HW problem. I am actually writing a
parser for a full text search query language and want an implied AND between
words. Since my problem mapped so well to the calculator, I thought that
would be a clearer way to ask the question.


Thanks,


Dan Weinlader


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