Macro peel_ip::prelude::take_s

macro_rules! take_s {
    ( $ i : expr , $ count : expr ) => { ... };
}

take_s!(nb) => &str -> IResult<&str, &str> generates a parser consuming the specified number of characters

 // Desmond parser
 named!(take5<&str,&str>, take_s!( 5 ) );

 let a = "abcdefgh";

 assert_eq!(take5(a), Done("fgh", "abcde"));

 let b = "12345";

 assert_eq!(take5(b), Done("", "12345"));