Method peek

src/testdrive/src/parser.rs:586–591

(&mut self)

    }

    fn peek(&mut self) -> Option<&(usize, String)> {
        if self.next.is_none() {
            self.next = Some(self.read_one())
        }
        self.next.as_ref().unwrap().as_ref()
    }

    pub fn line_col(&self, pos: usize) -> (usize, usize) {
        let (base_pos, (line, col)) = self.pos_map.range(..=pos).next_back().unwrap();