day1 part 2 (but manual parser)

src/bin/day1.rs

@@ -2,13 +2,103 @@
 
 use aoc23::read;
 use chumsky::prelude::*;
+use std::{io::{BufReader, BufRead}, fs::File};
+use chumsky::chain::Chain;
 
-fn parser() -> impl Parser<char, (), Error = Simple<char>> {
-	end()
+struct Line {
+	first_digit: u128,
+	last_digit: u128
+}
+
+// thanks rust
+fn array<T, const N: usize>(array: &'static [T; N]) -> &'static [T] {
+	array
+}
+
+impl Line {
+	fn parser() -> impl Parser<char, Self, Error = Simple<char>> {
+		choice((
+			// digit combinations (only the relevant ones)
+			just("oneight").map(|_| array(&[1, 8])),
+			just("twoone").map(|_| array(&[2, 1])),
+			just("eightwo").map(|_| array(&[8, 2])),
+
+			// single digits
+			just("one").or(just("1")).map(|_| array(&[1])),
+			just("two").or(just("2")).map(|_| array(&[2])),
+			just("three").or(just("3")).map(|_| array(&[3])),
+			just("four").or(just("4")).map(|_| array(&[4])),
+			just("five").or(just("5")).map(|_| array(&[5])),
+			just("six").or(just("6")).map(|_| array(&[6])),
+			just("seven").or(just("7")).map(|_| array(&[7])),
+			just("eight").or(just("8")).map(|_| array(&[8])),
+			just("nine").or(just("9")).map(|_| array(&[9])),
+
+			// garbage
+			none_of(['1', '2', '3', '4', '5', '6', '7', '8', '9', '\n'])
+				.map(|_| array(&[]))
+		))
+		.repeated()
+		.then_ignore(just('\n'))
+		.map(|digits: Vec<&'static [u128]>| {
+			let mut digits = digits.into_iter().flat_map(|array| array.iter().copied());
+			let first_digit = digits.next().expect("No digit in line");
+			let last_digit = digits.last().unwrap_or(first_digit);
+			Line {
+				first_digit,
+				last_digit
+			}
+		})
+	}
+}
+
+fn parser() -> impl Parser<char, Vec<Line>, Error = Simple<char>> {
+	Line::parser().repeated().then_ignore(end())
 }
 
 fn main() -> anyhow::Result<()> {
-	let _ = read("input.txt", parser())?;
+	let lines = read("inputs/day1.txt", parser())?;
+
+	let sum: u128 = lines
+		.iter()
+		.map(|line| line.first_digit * 10 + line.last_digit)
+		// .map(|number| { eprintln!("{number}"); number })
+		.sum();
+	println!("{sum}");
+
+	let mut sum: u128 = 0;
+	for line in BufReader::new(File::open("inputs/day1.txt")?).lines() {
+		let line = line?;
+		let line = line.trim();
+		if line.is_empty() {
+			continue;
+		}
+
+		let mut digits = Vec::new();
+		for i in 0 .. line.len() {
+			let s = &line[i..];
+
+			macro_rules! check_digit {
+				($digit:literal, $string:literal) => {
+					if s.starts_with(stringify!($digit)) || line[i..].starts_with($string) {
+						digits.push($digit);
+					}
+				}
+			}
+
+			check_digit!(1, "one");
+			check_digit!(2, "two");
+			check_digit!(3, "three");
+			check_digit!(4, "four");
+			check_digit!(5, "five");
+			check_digit!(6, "six");
+			check_digit!(7, "seven");
+			check_digit!(8, "eight");
+			check_digit!(9, "nine");
+		}
+		sum += digits.first().unwrap() * 10 + digits.last().unwrap();
+	}
+	println!("{sum}");
 
 	Ok(())
 }