Function split_path_and_revision 

pub fn split_path_and_revision<'a>(
    path: Option<&'a str>,
    state: Option<&'a str>,
) -> (Option<&'a str>, Option<&'a str>, Option<&'a str>)

Split --path / --state into a file target, a state target, and a historical revision to read.

--path always names a file. --state with --path is the historical revision of that file. --state alone is a state-level target.