`order.reverse` (#476)

1 files changed, 18 insertions, 4 deletions

diff --git a/src/gleam/order.gleam b/src/gleam/order.gleam
index 77ad033..12ce011 100644
--- a/src/gleam/order.gleam
+++ b/src/gleam/order.gleam
@@ -18,21 +18,21 @@ pub type Order {
 /// ## Examples
 ///
 /// ```gleam
-/// > reverse(Lt)
+/// > negate(Lt)
 /// Gt
 /// ```
 ///
 /// ```gleam
-/// > reverse(Eq)
+/// > negate(Eq)
 /// Eq
 /// ```
 ///
 /// ```gleam
-/// > reverse(Lt)
+/// > negate(Lt)
 /// Gt
 /// ```
 ///
-pub fn reverse(order: Order) -> Order {
+pub fn negate(order: Order) -> Order {
   case order {
     Lt -> Gt
     Eq -> Eq
@@ -117,3 +117,17 @@ pub fn min(a: Order, b: Order) -> Order {
     _, _ -> b
   }
 }
+
+/// Inverts an ordering function, so less-than becomes greater-than and greater-than
+/// becomes less-than.
+///
+/// ## Examples
+///
+/// ```gleam
+/// > list.sort([1, 5, 4], by: reverse(int.compare))
+/// [5, 4, 1]
+/// ```
+///
+pub fn reverse(orderer: fn(a, a) -> Order) -> fn(a, a) -> Order {
+  fn(a, b) { orderer(b, a) }
+}