From 07016d1ea6dd1806148f5bc32c38b0daa43438da Mon Sep 17 00:00:00 2001
From: cpustejovsky <charles.pustejovsky@gmail.com>
Date: Sat, 26 Nov 2022 20:53:42 -0500
Subject: [PATCH] feat: add generic copySlice function for pure package along
 with reverseSort helper function;

add tests that ensure the incoming slice is not mutated
---
 pure/pure.go                           | 55 ++++++++++++++++++++++++++
 sort/sort_test.go => pure/pure_test.go | 22 +++++++----
 sort/sort.go                           | 47 ----------------------
 3 files changed, 69 insertions(+), 55 deletions(-)
 create mode 100644 pure/pure.go
 rename sort/sort_test.go => pure/pure_test.go (71%)
 delete mode 100644 sort/sort.go

diff --git a/pure/pure.go b/pure/pure.go
new file mode 100644
index 0000000..23b0116
--- /dev/null
+++ b/pure/pure.go
@@ -0,0 +1,55 @@
+package pure
+
+import (
+	"sort"
+)
+
+type Item interface {
+	int | float64 | string
+}
+
+func reserveSort(x sort.Interface) {
+	sort.Sort(sort.Reverse(x))
+}
+
+func copySlice[I Item](original []I) []I {
+	c := make([]I, len(original))
+	copy(c, original)
+	return c
+}
+
+func NewSortedIntegers(ints []int) []int {
+	n := copySlice(ints)
+	sort.IntSlice(n).Sort()
+	return n
+}
+
+func NewSortedFloats(float64s []float64) []float64 {
+	n := copySlice(float64s)
+	sort.Float64Slice(n).Sort()
+	return n
+}
+
+func NewSortedStrings(strings []string) []string {
+	s := copySlice(strings)
+	sort.StringSlice(s).Sort()
+	return append(s)
+}
+
+func NewReverseSortedIntegers(integers []int) []int {
+	n := copySlice(integers)
+	reserveSort(sort.IntSlice(n))
+	return n
+}
+
+func NewReverseSortedFloats(float64s []float64) []float64 {
+	n := copySlice(float64s)
+	reserveSort(sort.Float64Slice(n))
+	return n
+}
+
+func NewReverseSortedStrings(strings []string) []string {
+	s := copySlice(strings)
+	reserveSort(sort.StringSlice(s))
+	return s
+}
diff --git a/sort/sort_test.go b/pure/pure_test.go
similarity index 71%
rename from sort/sort_test.go
rename to pure/pure_test.go
index 7df8928..d17832a 100644
--- a/sort/sort_test.go
+++ b/pure/pure_test.go
@@ -1,7 +1,7 @@
-package sort_test
+package pure_test
 
 import (
-	csgo "github.com/cpustejovsky/customsortgo/sort"
+	"github.com/cpustejovsky/customsortgo/pure"
 	"github.com/stretchr/testify/assert"
 	"testing"
 )
@@ -9,41 +9,47 @@ import (
 func TestSortForStrings(t *testing.T) {
 	w := []string{"cat", "albatross", "dolphin", "bee", "zebra", "aardvark"}
 	want := []string{"aardvark", "albatross", "bee", "cat", "dolphin", "zebra"}
-	got := csgo.NewSortedStrings(w)
+	got := pure.NewSortedStrings(w)
 	assert.Equal(t, want, got)
+	assert.NotEqual(t, got, w)
 }
 
 func TestReverseSortForStrings(t *testing.T) {
 	w := []string{"cat", "albatross", "dolphin", "bee", "zebra", "aardvark"}
 	want := []string{"zebra", "dolphin", "cat", "bee", "albatross", "aardvark"}
-	got := csgo.NewReverseSortedStrings(w)
+	got := pure.NewReverseSortedStrings(w)
 	assert.Equal(t, want, got)
+	assert.NotEqual(t, got, w)
 }
 
 func TestSortInts(t *testing.T) {
 	n := []int{1, 3, 5, 2, 7, 6, 4}
 	want := []int{1, 2, 3, 4, 5, 6, 7}
-	got := csgo.NewSortedIntegers(n)
+	got := pure.NewSortedIntegers(n)
 	assert.Equal(t, want, got)
+	assert.NotEqual(t, got, n)
 }
 
 func TestReverseSortInts(t *testing.T) {
 	n := []int{1, 3, 5, 2, 7, 6, 4}
 	want := []int{7, 6, 5, 4, 3, 2, 1}
-	got := csgo.NewReverseSortedIntegers(n)
+	got := pure.NewReverseSortedIntegers(n)
 	assert.Equal(t, want, got)
+	assert.NotEqual(t, got, n)
 }
 
 func TestSortFloat64s(t *testing.T) {
 	n := []float64{1.1, 3.3, 5.5, 2.2, 7.7, 6.6, 4.4}
 	want := []float64{1.1, 2.2, 3.3, 4.4, 5.5, 6.6, 7.7}
-	got := csgo.NewSortedFloats(n)
+	got := pure.NewSortedFloats(n)
 	assert.Equal(t, want, got)
+	assert.NotEqual(t, got, n)
 }
 
 func TestReverseSortFloat64s(t *testing.T) {
 	n := []float64{1.1, 3.3, 5.5, 2.2, 7.7, 6.6, 4.4}
 	want := []float64{7.7, 6.6, 5.5, 4.4, 3.3, 2.2, 1.1}
-	got := csgo.NewReverseSortedFloats(n)
+	got := pure.NewReverseSortedFloats(n)
 	assert.Equal(t, want, got)
+	assert.NotEqual(t, got, n)
 }
diff --git a/sort/sort.go b/sort/sort.go
deleted file mode 100644
index 697366d..0000000
--- a/sort/sort.go
+++ /dev/null
@@ -1,47 +0,0 @@
-package sort
-
-import (
-	"sort"
-)
-
-func NewSortedIntegers(nums []int) []int {
-	n := make([]int, len(nums))
-	copy(n, nums)
-	sort.IntSlice(n).Sort()
-	return n
-}
-
-func NewSortedFloats(nums []float64) []float64 {
-	n := make([]float64, len(nums))
-	copy(n, nums)
-	sort.Float64Slice(n).Sort()
-	return n
-}
-
-func NewSortedStrings(strs []string) []string {
-	s := make([]string, len(strs))
-	copy(s, strs)
-	sort.StringSlice(s).Sort()
-	return s
-}
-
-func NewReverseSortedIntegers(nums []int) []int {
-	n := make([]int, len(nums))
-	copy(n, nums)
-	sort.Sort(sort.Reverse(sort.IntSlice(n)))
-	return n
-}
-
-func NewReverseSortedFloats(nums []float64) []float64 {
-	n := make([]float64, len(nums))
-	copy(n, nums)
-	sort.Sort(sort.Reverse(sort.Float64Slice(n)))
-	return n
-}
-
-func NewReverseSortedStrings(strs []string) []string {
-	s := make([]string, len(strs))
-	copy(s, strs)
-	sort.Sort(sort.Reverse(sort.StringSlice(s)))
-	return s
-}