Add toLower and toUpper functions

README.md

@@ -371,6 +371,8 @@ For example, this is a JSON version of an emitted RuntimeContainer struct:
 * *`trimPrefix $prefix $string`*: If `$prefix` is a prefix of `$string`, return `$string` with `$prefix` trimmed from the beginning. Otherwise, return `$string` unchanged.
 * *`trimSuffix $suffix $string`*: If `$suffix` is a suffix of `$string`, return `$string` with `$suffix` trimmed from the end. Otherwise, return `$string` unchanged.
 * *`trim $string`*: Removes whitespace from both sides of `$string`.
+* *`toLower $string`*: Replace capital letters in `$string` to lowercase.
+* *`toUpper $string`*: Replace lowercase letters in `$string` to uppercase.
 * *`when $condition $trueValue $falseValue`*: Returns the `$trueValue` when the `$condition` is `true` and the `$falseValue` otherwise
 * *`where $items $fieldPath $value`*: Filters an array or slice based on the values of a field path expression `$fieldPath`. A field path expression is a dot-delimited list of map keys or struct member names specifying the path from container to a nested value. Returns an array of items having that value.
 * *`whereNot $items $fieldPath $value`*: Filters an array or slice based on the values of a field path expression `$fieldPath`. A field path expression is a dot-delimited list of map keys or struct member names specifying the path from container to a nested value. Returns an array of items **not** having that value.

template.go

@@ -409,6 +409,16 @@ func trim(s string) string {
 	return strings.TrimSpace(s)
 }
 
+// toLower return the string in lower case
+func toLower(s string) string {
+	return strings.ToLower(s)
+}
+
+// toUpper return the string in upper case
+func toUpper(s string) string {
+	return strings.ToUpper(s)
+}
+
 // when returns the trueValue when the condition is true and the falseValue otherwise
 func when(condition bool, trueValue, falseValue interface{}) interface{} {
 	if condition {
@@ -447,6 +457,8 @@ func newTemplate(name string) *template.Template {
 		"trimPrefix":             trimPrefix,
 		"trimSuffix":             trimSuffix,
 		"trim":                   trim,
+		"toLower":                toLower,
+		"toUpper":                toUpper,
 		"when":                   when,
 		"where":                  where,
 		"whereNot":               whereNot,

template_test.go

@@ -709,6 +709,24 @@ func TestTrim(t *testing.T) {
 	}
 }
 
+func TestToLower(t *testing.T) {
+	const str = ".RaNd0m StrinG_"
+	const lowered = ".rand0m string_"
+	got := toLower(str)
+	if got != lowered {
+		t.Fatalf("Expected toLower(%s) to be '%s', got '%s'", str, lowered, got)
+	}
+}
+
+func TestToUpper(t *testing.T) {
+	const str = ".RaNd0m StrinG_"
+	const uppered = ".RAND0M STRING_"
+	got := toUpper(str)
+	if got != uppered {
+		t.Fatalf("Expected toUpper(%s) to be '%s', got '%s'", str, uppered, got)
+	}
+}
+
 func TestDict(t *testing.T) {
 	containers := []*RuntimeContainer{
 		&RuntimeContainer{