Add some missing APIs for set/map

std/compact_map.oc

@@ -154,6 +154,19 @@ def Map::at(&this, key: K): V {
     return item.value
 }
 
+def Map::contains(&this, key: K): bool {
+    let hash = key.hash()
+    let index = .get_index(key, hash)
+    return .indices[index] != INDEX_FREE
+}
+
+def Map::clear(&this) {
+    .items.clear()
+    for let i = 0; i < .capacity; i++ {
+        .indices[i] = INDEX_FREE
+    }
+}
+
 def Map::is_empty(&this): bool => .items.size == 0
 
 def Map::iter(&this): Iterator<Item<K, V>> => .items.iter()

std/map.oc

@@ -199,6 +199,17 @@ def Map::free(&this) {
         .buckets[i].free_list()
     }
     free(.buckets)
+    free(this)
+}
+
+//* Clears the map
+def Map::clear(&this) {
+    for let i = 0; i < .num_buckets; i += 1 {
+        .buckets[i].free_list()
+        .buckets[i] = null
+    }
+    .num_items = 0
+    .num_collisions = 0
 }
 
 //* Returns an iterator over the map

std/set.oc

@@ -25,6 +25,10 @@ def Set::size(&this): u32 {
     return .map.num_items
 }
 
+def Set::clear(&this) {
+    .map.clear()
+}
+
 def Set::extend(&this, other: &Set<T>) {
     .map.extend(other.map)
 }