pub fn peek(&self) -> char {
        if self.at_eof() {
            return '\0';
        }
        self.source_char_list[self.current + 1] 
    }
/// Returns the next character after `current`-th without consuming it.
Returns the next character after `current`-th without consuming it.
Returns the next character after ` current ` - th without consuming it .
pub fn peek(&self) -> char {
        if self.at_eof() {
            return '\0';
        }
        self.source_char_list[self.current + 1] 
    }
pub fn peek ( & self ) -> char { if self . at_eof ( ) { return '\0' ; } self . source_char_list [ self . current + 1 ] }
Returns the next character after `current`-th without consuming it.
Returns the next character after ` current ` - th without consuming it .
&self