#1264 Add .range() method to sorted_map and sorted_set

sorted_map/map.mbt

@@ -241,6 +241,17 @@ pub impl[K : @quickcheck.Arbitrary + Compare, V : @quickcheck.Arbitrary] @quickc
   @quickcheck.Arbitrary::arbitrary(size, rs) |> T::from_iter
 }
 
+///|Returns a new array of key-value pairs that are within the specified range [low, high).
+pub fn range[K : Compare, V](
+  self : T[K, V],
+  low : K,
+  high : K
+) -> Array[(K, V)] {
+  let result = []
+  self.each(fn(k, v) { if k >= low && k <= high { result.push((k, v)) } })
+  result
+}
+
 // AVL tree operations
 
 ///|

sorted_map/map_test.mbt

@@ -211,3 +211,14 @@ test "iter" {
   }
   inspect!(buf, content="[1a][2b][3c]")
 }
+
+test "range" {
+  let map = @sorted_map.of([(1, "a"), (2, "b"), (3, "c"), (4, "d"), (5, "e")])
+  let result = map.range(2, 4)
+  inspect!(
+    result,
+    content=
+      #|[(2, "b"), (3, "c"), (4, "d")]
+    ,
+  )
+}

sorted_map/sorted_map.mbti

@@ -24,6 +24,7 @@ impl T {
   op_equal[K : Eq, V : Eq](Self[K, V], Self[K, V]) -> Bool
   op_get[K : Compare, V](Self[K, V], K) -> V?
   op_set[K : Compare, V](Self[K, V], K, V) -> Unit
+  range[K : Compare, V](Self[K, V], K, K) -> Array[(K, V)]
   remove[K : Compare, V](Self[K, V], K) -> Unit
   size[K, V](Self[K, V]) -> Int
   to_array[K, V](Self[K, V]) -> Array[(K, V)]

sorted_set/set.mbt

@@ -450,6 +450,13 @@ fn to_array[T](self : Node[T]) -> Array[T] {
   aux(Some(self))
 }
 
+///|
+pub fn range[V : Compare](self : T[V], low : V, high : V) -> Array[V] {
+  let result = []
+  self.each(fn(x) { if x >= low && x <= high { result.push(x) } })
+  result
+}
+
 // AVL tree operations
 
 ///|

sorted_set/set_test.mbt

@@ -222,3 +222,9 @@ test "from_iter empty iter" {
   let pq : @sorted_set.T[Int] = @sorted_set.T::from_iter(Iter::empty())
   inspect!(pq, content="@sorted_set.of([])")
 }
+
+test "range" {
+  let set = @sorted_set.of([1, 2, 3, 4, 5])
+  let result = set.range(2, 4)
+  inspect!(result, content="[2, 3, 4]")
+}

sorted_set/sorted_set.mbti

@@ -26,6 +26,7 @@ impl T {
   is_empty[V : Compare](Self[V]) -> Bool
   iter[V](Self[V]) -> Iter[V]
   op_equal[V : Compare](Self[V], Self[V]) -> Bool
+  range[V : Compare](Self[V], V, V) -> Array[V]
   remove[V : Compare](Self[V], V) -> Unit
   size[V : Compare](Self[V]) -> Int64
   subset[V : Compare](Self[V], Self[V]) -> Bool