use logos::Logos;

 #[derive(Logos, Debug, PartialEq)]
 #[logos(skip r"[ \t\n\f]+")] // Ignore this regex pattern between tokens
 enum Token {
     // Tokens can be literal strings, of any length.
     #[token("fast")]
     Fast,

     #[token(".")]
     Period,

     // Or regular expressions.
     #[regex("[a-zA-Z]+")]
     Text,
 }

 fn main() {
     let mut lex = Token::lexer("Create ridiculously fast Lexers.");

     assert_eq!(lex.next(), Some(Ok(Token::Text)));
     assert_eq!(lex.span(), 0..6);
     assert_eq!(lex.slice(), "Create");

     assert_eq!(lex.next(), Some(Ok(Token::Text)));
     assert_eq!(lex.span(), 7..19);
     assert_eq!(lex.slice(), "ridiculously");

     assert_eq!(lex.next(), Some(Ok(Token::Fast)));
     assert_eq!(lex.span(), 20..24);
     assert_eq!(lex.slice(), "fast");

     assert_eq!(lex.next(), Some(Ok(Token::Text)));
     assert_eq!(lex.slice(), "Lexers");
     assert_eq!(lex.span(), 25..31);

     assert_eq!(lex.next(), Some(Ok(Token::Period)));
     assert_eq!(lex.span(), 31..32);
     assert_eq!(lex.slice(), ".");

     assert_eq!(lex.next(), None);
 }