Method next

cranelift/reader/src/lexer.rs:477–538

Get the next token or a lexical error. Return None when the end of the source is encountered.

(&mut self)

    ///
    /// Return None when the end of the source is encountered.
    pub fn next(&mut self) -> Option<Result<LocatedToken<'a>, LocatedError>> {
        loop {
            let loc = self.loc();
            return match self.lookahead {
                None => None,
                Some(';') => Some(self.scan_comment()),
                Some('(') => Some(self.scan_char(Token::LPar)),
                Some(')') => Some(self.scan_char(Token::RPar)),
                Some('{') => Some(self.scan_char(Token::LBrace)),
                Some('}') => Some(self.scan_char(Token::RBrace)),
                Some('[') => Some(self.scan_char(Token::LBracket)),
                Some(']') => Some(self.scan_char(Token::RBracket)),
                Some('<') => Some(self.scan_char(Token::LAngle)),
                Some('>') => Some(self.scan_char(Token::RAngle)),
                Some(',') => Some(self.scan_char(Token::Comma)),
                Some('.') => Some(self.scan_char(Token::Dot)),
                Some(':') => Some(self.scan_char(Token::Colon)),
                Some('=') => Some(self.scan_char(Token::Equal)),
                Some('!') => Some(self.scan_char(Token::Bang)),
                Some('+') => Some(self.scan_number()),
                Some('*') => Some(self.scan_char(Token::Multiply)),
                Some('-') => {
                    if self.looking_at("->") {
                        Some(self.scan_chars(2, Token::Arrow))
                    } else {
                        Some(self.scan_number())
                    }
                }
                Some('0'..='9') => Some(self.scan_number()),
                Some('a'..='z') | Some('A'..='Z') => {
                    if self.looking_at("NaN") || self.looking_at("Inf") {
                        Some(self.scan_number())
                    } else {
                        Some(self.scan_word())
                    }
                }
                Some('%') => Some(self.scan_name()),
                Some('"') => Some(self.scan_string()),
                Some('#') => Some(self.scan_hex_sequence()),
                Some('@') => {
                    let pos = self.pos;
                    let loc = self.loc();
                    self.next_ch();
                    if self.looking_at_srcloc() {
                        Some(self.scan_srcloc(pos, loc))
                    } else {
                        Some(token(Token::At, loc))
                    }
                }
                // all ascii whitespace
                Some(' ') | Some('\x09'..='\x0d') => {
                    self.next_ch();
                    continue;
                }
                _ => {
                    // Skip invalid char, return error.
                    self.next_ch();
                    Some(error(LexError::InvalidChar, loc))