A few general questions regarding IF

I don’t think anybody’s written out a BNF for Inform 6 but the language’s syntax is summarized at inform-fiction.org/manual/html/tables.html. For Inform 7, see the documents at the top of this thread: https://intfiction.org/t/the-list-of-inform-7-documentation-as-of-19-dec-2011/3311/1