oh neat. A three bit digest. The const's are inlined once used

src/main.rs

@@ -1,16 +1,15 @@
+const DIGEST_SIZE: usize = 3;
+const ZERO: Option<u8> = Some(42);
+
+fn compute_digest(text: &str) -> [u8; DIGEST_SIZE] {
+    let mut digest = [ZERO.unwrap_or(0); DIGEST_SIZE];
+    for (idx, &b) in text.as_bytes().iter().enumerate() {
+        digest[idx % DIGEST_SIZE] = digest[idx % DIGEST_SIZE].wrapping_add(b)
+    }
+    return digest;
+}
+
 fn main() {
-    let x = 10;
-    let y = 20;
-
-    takes_u32(x);
-    takes_i8(y);
-    takes_u32(y.try_into().unwrap());
-}
-
-fn takes_u32(x: u32) -> () {
-    println!("{x}");
-}
-
-fn takes_i8(x: i8) -> () {
-    println!("{x}");
+    let digest = compute_digest("Hello");
+    println!("digest: {digest:?}");
 }