From c5522bcca9c70f75f8248ac23cea2130bbbf53a5 Mon Sep 17 00:00:00 2001
From: Fraser Waters <fraser@pulumi.com>
Date: Sat, 16 Sep 2023 22:31:43 +0100
Subject: [PATCH] Add Sorted method

This is a varient on `slices.Sorted` that makes it easy to get a sorted slice. This makes it easy to get the elements of the set into a sorted slice. Quite handy when using sets to build up unique elements but then needing a well defined iteration order.
---
 set.go      | 13 +++++++++++++
 set_test.go | 28 ++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/set.go b/set.go
index 4c52c8e..6f0b971 100644
--- a/set.go
+++ b/set.go
@@ -35,6 +35,11 @@ SOFTWARE.
 // that can enforce mutual exclusion through other means.
 package mapset
 
+import (
+	"cmp"
+	"slices"
+)
+
 // Set is the primary interface provided by the mapset package.  It
 // represents an unordered set of data and a large number of
 // operations that can be applied to that set.
@@ -243,3 +248,11 @@ func NewThreadUnsafeSetFromMapKeys[T comparable, V any](val map[T]V) Set[T] {
 
 	return s
 }
+
+// Sorted returns a sorted slice of a set of any ordered type in ascending order.
+// When sorting floating-point numbers, NaNs are ordered before other values.
+func Sorted[E cmp.Ordered](set Set[E]) []E {
+	s := set.ToSlice()
+	slices.Sort(s)
+	return s
+}
diff --git a/set_test.go b/set_test.go
index 23e8f09..b7a347f 100644
--- a/set_test.go
+++ b/set_test.go
@@ -1298,6 +1298,34 @@ func Test_NewThreadUnsafeSetFromMapKey_Strings(t *testing.T) {
 	}
 }
 
+func Test_Sorted(t *testing.T) {
+	test := func(t *testing.T, ctor func(vals ...string) Set[string]) {
+		set := ctor("apple", "banana", "pear")
+		sorted := Sorted(set)
+
+		if len(sorted) != set.Cardinality() {
+			t.Errorf("Length of slice is not the same as the set. Expected: %d. Actual: %d", set.Cardinality(), len(sorted))
+		}
+
+		if sorted[0] != "apple" {
+			t.Errorf("Element 0 was not equal to apple: %s", sorted[0])
+		}
+		if sorted[1] != "banana" {
+			t.Errorf("Element 0 was not equal to banana: %s", sorted[1])
+		}
+		if sorted[2] != "pear" {
+			t.Errorf("Element 0 was not equal to pear: %s", sorted[2])
+		}
+	}
+
+	t.Run("Safe", func(t *testing.T) {
+		test(t, NewSet[string])
+	})
+	t.Run("Unsafe", func(t *testing.T) {
+		test(t, NewThreadUnsafeSet[string])
+	})
+}
+
 func Test_Example(t *testing.T) {
 	/*
 	   requiredClasses := NewSet()