What% prec 'does. mean here in yacc?

Question

notype_declarator:
      notype_declarator '(' parmlist_or_identifiers  %prec '.'
        { $$ = build_nt (CALL_EXPR, $1, $3, NULL_TREE); }

Is anyone familiar with yacc rules?

Answer 1

He announces that this construct has the same priority as '.' operator that will be specified earlier.

Answer 2

Yacc program to display errors for 1) variable override 2) Assignment expression error 3) missing operator