// convert &str to Option<String>
#[allow(unused_macros)]// currently only used in tests
macro_rules!opt_str{($x:expr)=>(Some($x.to_string()));}#[allow(unused_imports)]// currently only used in tests
pub(crate)use opt_str;// convert Vec<&str> to Vec<String>
macro_rules!vec_str{($x:expr)=>($x.iter().map(|&s|s.to_string()).collect());}pub(crate)use vec_str;