reverse

docs/templatefuncs.md

@@ -183,6 +183,16 @@ far
 adcda
 ```
 
+## `reverse` *list*
+
+`reverse` returns a copy of *list* in reverse order.
+
+```text
+{{ list "a" "b" "c" }}
+
+[c b a]
+```
+
 ## `stat` *path*
 
 `stat` returns a map representation of executing

templatefuncs.go

@@ -49,6 +49,7 @@ func NewFuncMap() template.FuncMap {
 		"quote":            eachString(strconv.Quote),
 		"regexpReplaceAll": regexpReplaceAllTemplateFunc,
 		"replaceAll":       replaceAllTemplateFunc,
+		"reverse":          reverseTemplateFunc,
 		"stat":             eachString(statTemplateFunc),
 		"toJSON":           toJSONTemplateFunc,
 		"toLower":          eachString(strings.ToLower),
@@ -170,6 +171,14 @@ func regexpReplaceAllTemplateFunc(expr, repl, s string) string {
 	return regexp.MustCompile(expr).ReplaceAllString(s, repl)
 }
 
+// reverseTemplateFunc is the core implementation of the `reverse`
+// template function.
+func reverseTemplateFunc(list []any) []any {
+	listcopy := append([]any(nil), list...)
+	slices.Reverse(listcopy)
+	return listcopy
+}
+
 // statTemplateFunc is the core implementation of the `stat` template function.
 func statTemplateFunc(name string) any {
 	switch fileInfo, err := os.Stat(name); {

templatefuncs_test.go

@@ -145,6 +145,10 @@ func TestFuncMap(t *testing.T) {
 			template: `{{ quote "a" }}`,
 			expected: `"a"`,
 		},
+		{
+			template: `{{ list "a" "b" "c" | reverse }}`,
+			expected: "[c b a]",
+		},
 		{
 			template: `{{ (stat "testdata/file").type }}`,
 			expected: "file",