Use function pointers over dyn traits

2021/src/lib.rs

@@ -1,29 +1,19 @@
 use std::io::Read;
 
+type Solution = fn(&mut dyn Read) -> String;
+
 mod day01;
 
-pub trait Solution {
-    fn part1(&mut self, input: &mut dyn Read) -> String;
-
-    fn part2(&mut self, _input: &mut dyn Read) -> String {
-        unimplemented!("Still working on part 1");
+pub fn get_implementation(day: usize, part2: bool) -> Solution {
+    if !part2 {
+        match day {
+            1 => day01::part1,
+            _ => panic!("Unsupported part one for day {}", day),
+        }
+    } else {
+        match day {
+            1 => day01::part2,
+            _ => panic!("Unsupported part two for day {}", day),
+        }
     }
 }
-
-pub fn get_implementation(day: usize) -> Box<dyn Solution> {
-    match day {
-        1 => Box::new(day01::Day01::default()),
-        _ => panic!("Unsupported day {}", day),
-    }
-}
-
-#[cfg(test)]
-fn test_implementation(mut day: impl Solution, part: u8, mut input: &[u8], answer: impl ToString) {
-    let result = match part {
-        1 => day.part1(&mut input),
-        2 => day.part2(&mut input),
-        _ => panic!("Invalid part: {}", part),
-    };
-
-    assert_eq!(answer.to_string(), result);
-}