Function rustc_lexer::unescape::unescape_literal

pub fn unescape_literal<F>(literal_text: &str, mode: Mode, callback: &mut F)where
    F: FnMut(Range<usize>, Result<char, EscapeError>),

Takes a contents of a literal (without quotes) and produces a sequence of escaped characters or errors. Values are returned through invoking of the provided callback.