Empty block rule in Bison?

Question

OK, so let me explain what I need :

• I've got a rule describing blocks, e.g. think of C-like languages' { .. }

• A block may contain statements, with the rule defined (rather obviously) like :

  statements   :   statement
               |   statements[previous] statement
               ;
  

---

Now here's the catch :

What if I want a block of code, or a statements rule to be also valid if it contains... nothing at all, or - to make it even more universal - to have a perfectly valid program which contains nothing.

Attempting to add... nothingness into a rule, quite obviously as well, results in like 100+ shift-reduce conflicts.

How should I go about that? Most definitely, having the parser throw syntax errors because there is no statement, doesn't make much sense, does it?

Answer 1

Well, that was simple after all :

    statements   :   statements[previous] statement
                 |   /* empty */
                 ;

And fixed. No shift-reduce conflicts, whatsoever.