Method parse_at_most_one_keyword

src/sql-parser/src/parser.rs:1862–1890

(
        &mut self,
        keywords: &[Keyword],
        location: &str,
    )

    }

    fn parse_at_most_one_keyword(
        &mut self,
        keywords: &[Keyword],
        location: &str,
    ) -> Result<Option<Keyword>, ParserError> {
        match self.parse_one_of_keywords(keywords) {
            Some(first) => {
                let remaining_keywords = keywords
                    .iter()
                    .cloned()
                    .filter(|k| *k != first)
                    .collect::<Vec<_>>();
                if let Some(second) = self.parse_one_of_keywords(remaining_keywords.as_slice()) {
                    let second_pos = self.peek_prev_pos();
                    parser_err!(
                        self,
                        second_pos,
                        "Cannot specify both {} and {} in {}",
                        first,
                        second,
                        location,
                    )
                } else {
                    Ok(Some(first))
                }
            }
            None => Ok(None),
        }
    }

    /// Look for one of the given keywords and return the one that matches.
    #[must_use]