dev-lang/bas/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <use>
    <flag name="lr0">Use the LR0 parser instead of the recursive descending parser</flag>
  </use>
</pkgmetadata>