made no_alloc map (untested)

outside/src/arraymap.rs

@@ -0,0 +1,58 @@
+/// no_std, no_alloc map
+pub struct ArrayMap<const N: usize, K,V> {
+    keys: [Option<K>; N],
+    values: [Option<V>; N],
+    index: usize,
+}
+
+impl<const N: usize, K, V> ArrayMap<N, K, V> where K: Eq {
+    pub fn new() -> Self {
+        Self { keys: [const { None };N], values: [const { None };N], index: 0 }
+    }
+
+    pub fn insert(&mut self, key: K, value: V) {
+        match self.keys[..self.index].iter().enumerate()
+            .find(|k| k.1.as_ref().is_some_and(|v| *v == key)) {
+            Some((index, _)) => {
+                self.keys[index] = Some(key);
+                self.values[index] = Some(value);
+            },
+            None => {
+                self.keys[self.index] = Some(key);
+                self.values[self.index] = Some(value);
+                self.index += 1;
+                if self.index > N {
+                    self.index = 0;
+                    log::error!("arraymap is full, overwriting");
+                }
+            },
+        }
+    }
+
+    pub fn get(&self, key: K) -> Option<&V> {
+        match self.keys[..self.index].iter().enumerate()
+            .find(|k| k.1.as_ref().is_some_and(|v| *v == key)) {
+            Some((index, _)) => {
+                self.values[index].as_ref()
+            },
+            None => {
+                None
+            },
+        }
+    }
+}
+
+#[cfg(test)] 
+mod test {
+    use super::ArrayMap;
+
+    fn get() {
+        let mut map: ArrayMap<2, i32, &str> = ArrayMap::new();
+
+        map.insert(3, "fogey");
+        map.insert(4, "bogey");
+
+        assert_eq!(map.get(3), Some(&"fogey"));
+        assert_eq!(map.get(5), None);
+    }
+}