crafting-interpreters/rust/rox/src/tokenizer/newline.rs

use super::interface::Tokenizer;
use crate::token::Token;
use std::{iter::Peekable, str::CharIndices};

/// Consume newlines. Do not yield a token but increase the current line.
pub struct Newline;
impl Tokenizer for Newline {
    fn run(
        &self,
        c: (usize, char),
        _chars: &mut Peekable<CharIndices<'_>>,
        _source: &str,
        _line: usize,
    ) -> Option<(usize, Option<Token>)> {
        match c.1 {
            '\n' => Some((1, None)),
            _ => None,
        }
    }
}