//! How to require presence of at least N values, //! //! This program accepts "-f -f -f" or "-fffff" but not "-f" use bpaf::*; fn main() { let opt = short('f') .req_flag(()) .many() .guard(|x| x.len() >= 2, "at least two arguments are required") .to_options() .run(); println!("{:?}", opt); }