fn bump(&mut self) -> Option<(ByteIndex, char)> {
        let current = self.lookahead();
        self.lookahead = self.chars.next();
        current
    }
/// Bump the current position in the source string by one character,
/// returning the current character and byte position.
Bump the current position in the source string by one character,
returning the current character and byte position.
Bump the current position in the source string by one character returning the current character and byte position .
fn bump(&mut self) -> Option<(ByteIndex, char)> {
        let current = self.lookahead();
        self.lookahead = self.chars.next();
        current
    }
fn bump ( & mut self ) -> Option < ( ByteIndex , char ) > { let current = self . lookahead ( ) ; self . lookahead = self . chars . next ( ) ; current }
Bump the current position in the source string by one character,
returning the current character and byte position.
Bump the current position in the source string by one character returning the current character and byte position .
&mut self
&mut self