3.7.1 Require a Version of Bison

You may require the minimum version of Bison to process the grammar. If the requirement is not met, bison exits with an error (exit status 63).

%require "version"

Some deprecated behaviors are disabled for some required version:

"3.2" (or better)

The C++ deprecated files position.hh and stack.hh are no longer generated.

"3.4" (or better)

To comply with the recommendations of the Graphviz team, use the .gv extension instead of .dot for the name of the generated DOT file. See Graphviz.