ebnf-ignore-empty-ruleebnf-ignore-empty-rule is a variable defined in `
ebnf2ps.el'. Its value is
nilDocumentation: Non-nil means ignore empty rules. It's interesting to set this variable if your Yacc/Bison grammar has a lot of middle action rule. You can customize this variable. This variable was introduced, or its default value was changed, in version 20 of Emacs.