It would be nice if subpatterns could be used within subpatterns.

#[derive(Logos, Copy, Clone, Debug)]
#[logos(subpattern a = r"[a-zA-Z!$%&*/:<=>?^_~]")]
#[logos(subpattern b = r"(?&a)|[0-9+\-.@]")]
pub enum Token {
    #[error]
    Error,
    // ...
}

Currently, this is not supported and causes a regex parse error.

I don't plan to learn troff, so this seems like a low-maintenance way to still have man pages.

https://www.gnu.org/software/help2man/

The parsers for floating point number are especially bad as they allocate memory. See #113 for further details.

Flex has a directive %option caseless to lex tokens in a case insensitive way.

Is there currently a way (besides using regular expressions) to accomplish the same?

പൊളിസാധനം എന്നാണ് മലയാളമെങ്കിലും ഹിറ്റായ ഐറ്റം പൊളിസാനം എന്ന നാടൻ പ്രയോഗമാണ്. വേണമെങ്കില്‍ pwoli_sanam എന്നാക്കാവുന്നതാണ്