Not exposing the initial capacity

hashmap/README.md

@@ -15,11 +15,11 @@ let map1 : HashMap[String, Int] = HashMap::new()
 let map2 = HashMap::[1, 2, 3, 4, 5]
 ```
 
-When creating via `new()`, you can set initial capacity and custom hasher by providing labeled argument `~capacity` and `~hasher`. Note that the capacity must be a zero or a power of 2.
+When creating via `new()`, you can set a custom hasher by providing a labeled argument `~hasher`. 
 
 ```moonbit
-// Create with custom hasher and capacity.
-let map = HashMap::new(~capacity=32, ~hasher=Some(fn(k) { k.length() }))
+// Create with custom hasher.
+let map = HashMap::new(~hasher=Some(fn(k) { k.length() }))
 ```
 
 ### Set & Get

hashmap/hashmap.mbt

@@ -48,25 +48,17 @@ struct HashMap[K, V] {
 
 /// Create new hash map.
 pub fn HashMap::new[K, V](
-  ~capacity : Int = default_init_capacity,
   ~hasher : Option[(K) -> Int] = None
 ) -> HashMap[K, V] {
-  if capacity != 0 && not(is_power_of_two(capacity)) {
-    abort("The capacity is not a zero or a power of 2.")
-  }
   {
     size: 0,
-    capacity,
-    growAt: calc_grow_threshold(capacity),
+    capacity: default_init_capacity,
+    growAt: calc_grow_threshold(default_init_capacity),
     hasher,
-    entries: @array.new(capacity, fn() { Empty }),
+    entries: @array.new(default_init_capacity, fn() { Empty }),
   }
 }
 
-fn is_power_of_two(n : Int) -> Bool {
-  n > 0 && n.land(n - 1) == 0
-}
-
 /// Create new hash map from array.
 pub fn HashMap::from_array[K : Hash + Eq, V](
   arr : Array[(K, V)]
@@ -297,8 +289,7 @@ test "new" {
 
 test "set" {
   let m : HashMap[String, Int] = HashMap::new(
-    ~hasher=Some(fn(k) { k.length() }),
-    ~capacity=16,
+    ~hasher=Some(fn(k) { k.length() })
   )
   m.set("a", 1)
   m.set("b", 1)
@@ -367,8 +358,7 @@ test "from_array" {
 
 test "remove" {
   let m : HashMap[String, Int] = HashMap::new(
-    ~hasher=Some(fn(k) { k.length() }),
-    ~capacity=16,
+    ~hasher=Some(fn(k) { k.length() })
   )
   m.set("a", 1)
   m.set("ab", 2)
@@ -380,7 +370,7 @@ test "remove" {
   @assertion.assert_eq(m.size(), 5)?
   @assertion.assert_eq(
     m.debug_entries(),
-    "_,(0,a,1),(0,bc,2),(1,cd,2),(1,abc,3),_,(0,abcdef,6),_,_,_,_,_,_,_,_,_",
+    "_,(0,a,1),(0,bc,2),(1,cd,2),(1,abc,3),_,(0,abcdef,6),_",
   )?
 }
 
@@ -406,11 +396,6 @@ test "size" {
   @assertion.assert_eq(m.size(), 1)?
 }
 
-test "capacity" {
-  let m : HashMap[String, Int] = HashMap::new(~capacity=128)
-  @assertion.assert_eq(m.capacity(), 128)?
-}
-
 test "is_empty" {
   let m : HashMap[String, Int] = HashMap::new()
   @assertion.assert_eq(m.is_empty(), true)?
@@ -475,12 +460,4 @@ test "grow" {
     m.debug_entries(),
     "_,(0,C,1),(0,Go,2),(0,C++,3),(0,Java,4),(0,Scala,5),(1,Julia,5),(2,Cobol,5),(2,Python,6),(2,Haskell,7),(2,Rescript,8),_,_,_,_,_",
   )?
-}
-
-test "zero_capacity_grow" {
-  let m : HashMap[String, Int] = HashMap::new(~capacity=0)
-  @assertion.assert_eq(m.capacity(), 0)?
-  m.set("a", 1)
-  @assertion.assert_eq(m.size(), 1)?
-  @assertion.assert_eq(m.capacity(), 8)?
-}
+}