Method parse_flags

regex/regex-syntax/src/ast/parse.rs:1319–1367

Parse a sequence of flags starting at the current character. This advances the parser to the character immediately following the flags, which is guaranteed to be either `:` or `)`. # Errors If any flags are duplicated, then an error is returned. If the negation operator is used more than once, then an error is returned. If no flags could be found or if the negation operation is not followed b

(&self)

    /// If no flags could be found or if the negation operation is not followed
    /// by any flags, then an error is returned.
    fn parse_flags(&self) -> Result<ast::Flags> {
        let mut flags = ast::Flags {
            span: self.span(),
            items: vec![],
        };
        let mut last_was_negation = None;
        while self.char() != ':' && self.char() != ')' {
            if self.char() == '-' {
                last_was_negation = Some(self.span_char());
                let item = ast::FlagsItem {
                    span: self.span_char(),
                    kind: ast::FlagsItemKind::Negation,
                };
                if let Some(i) = flags.add_item(item) {
                    return Err(self.error(
                        self.span_char(),
                        ast::ErrorKind::FlagRepeatedNegation {
                            original: flags.items[i].span,
                        },
                    ));
                }
            } else {
                last_was_negation = None;
                let item = ast::FlagsItem {
                    span: self.span_char(),
                    kind: ast::FlagsItemKind::Flag(self.parse_flag()?),
                };
                if let Some(i) = flags.add_item(item) {
                    return Err(self.error(
                        self.span_char(),
                        ast::ErrorKind::FlagDuplicate {
                            original: flags.items[i].span,
                        },
                    ));
                }
            }
            if !self.bump() {
                return Err(self.error(
                    self.span(),
                    ast::ErrorKind::FlagUnexpectedEof,
                ));
            }
        }
        if let Some(span) = last_was_negation {
            return Err(self.error(span, ast::ErrorKind::FlagDanglingNegation));
        }
        flags.span.end = self.pos();
        Ok(flags)
    }

    /// Parse the current character as a flag. Do not advance the parser.
    ///