From 7a31831ea528b4a8711af155ffcb443724f2a934 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Samuel=20=C5=A0ulovsk=C3=BD?= <samuel.sulovsky@gmail.com>
Date: Sat, 4 Mar 2023 21:40:12 +0100
Subject: [PATCH] arrays: sorting functions for immutable arrays

---
 vlib/arrays/arrays.v      | 20 ++++++++++++++++++++
 vlib/arrays/arrays_test.v | 29 +++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/vlib/arrays/arrays.v b/vlib/arrays/arrays.v
index fb3360e172..1e94ba887a 100644
--- a/vlib/arrays/arrays.v
+++ b/vlib/arrays/arrays.v
@@ -218,6 +218,26 @@ pub fn sum[T](array []T) !T {
 	}
 }
 
+// sorted returns a sorted clone of the array
+// Example: arrays.sorted([6, 2, 1, 0, 3]) // => [0, 1, 2, 3, 6]
+pub fn sorted[T](array []T) []T {
+	mut cloned := array.clone()
+	cloned.sort(a < b)
+	sorted := cloned.clone()
+
+	return sorted
+}
+
+// sorted_with_compare returns a sorted clone of the array, sorted with the provided sorting function
+// Example: arrays.sorted([6, 2, 1, 0, 3]) // => [0, 1, 2, 3, 6]
+pub fn sorted_with_compare[T](array []T, callback fn (&T, &T) int) []T {
+	mut cloned := array.clone()
+	cloned.sort_with_compare(callback)
+	sorted := cloned.clone()
+
+	return sorted
+}
+
 // reduce sets `acc = array[0]`, then successively calls `acc = reduce_op(acc, elem)` for each remaining element in `array`.
 // returns the accumulated value in `acc`.
 // returns an error if the array is empty.
diff --git a/vlib/arrays/arrays_test.v b/vlib/arrays/arrays_test.v
index 6180e505db..b17e4bed96 100644
--- a/vlib/arrays/arrays_test.v
+++ b/vlib/arrays/arrays_test.v
@@ -155,6 +155,35 @@ fn test_sum() {
 	assert sum[int]([]int{}) or { 0 } == 0
 }
 
+fn test_sorted() {
+	ints := [5, 1, 3, 4, 2]
+	ints_sorted := [1, 2, 3, 4, 5]
+
+	assert sorted[int](ints) == ints_sorted
+
+	strings := ['a', 'c', 'd', 'b', 'e']
+	strings_sorted := ['a', 'b', 'c', 'd', 'e']
+
+	assert sorted[string](strings) == strings_sorted
+}
+
+fn test_sorted_with_compare() {
+	strings := ['a', 'c', 'd', 'b', 'e']
+	strings_sorted := ['e', 'd', 'c', 'b', 'a']
+
+	descending_string_sort_fn := fn (a &string, b &string) int {
+		if *a > *b {
+			return -1
+		}
+		if *a < *b {
+			return 1
+		}
+		return 0
+	}
+
+	assert sorted_with_compare[string](strings, descending_string_sort_fn) == strings_sorted
+}
+
 fn test_reduce() {
 	x := [1, 2, 3, 4, 5]