Method raw

crates/ruff_python_formatter/src/string/normalize.rs:578–620

Computes if a raw string uses the preferred quote. If it does, then it's not possible to change the quote style because it would require escaping which isn't possible in raw strings.

(text: &str, preferred: Quote, triple_quotes: TripleQuotes)

    /// Computes if a raw string uses the preferred quote. If it does, then it's not possible
    /// to change the quote style because it would require escaping which isn't possible in raw strings.
    fn raw(text: &str, preferred: Quote, triple_quotes: TripleQuotes) -> Self {
        let mut chars = text.chars().peekable();
        let preferred_quote_char = preferred.as_char();

        let contains_unescaped_configured_quotes = loop {
            match chars.next() {
                Some('\\') => {
                    // Ignore escaped characters
                    chars.next();
                }
                // `"` or `'`
                Some(c) if c == preferred_quote_char => {
                    if triple_quotes.is_no() {
                        break true;
                    }

                    match chars.peek() {
                        // We can't turn `r'''\""'''` into `r"""\"""""`, this would confuse the parser
                        // about where the closing triple quotes start
                        None => break true,
                        Some(next) if *next == preferred_quote_char => {
                            // `""` or `''`
                            chars.next();

                            // We can't turn `r'''""'''` into `r""""""""`, nor can we have
                            // `"""` or `'''` respectively inside the string
                            if chars.peek().is_none() || chars.peek() == Some(&preferred_quote_char)
                            {
                                break true;
                            }
                        }
                        _ => {}
                    }
                }
                Some(_) => continue,
                None => break false,
            }
        };

        Self::Raw {
            contains_preferred: contains_unescaped_configured_quotes,
        }
    }
}

#[derive(Debug)]