feat: Add non-must template funcs with may prefix

internal/template/func_map.go

@@ -5,15 +5,27 @@ import (
 	"text/template"
 
 	"github.com/Masterminds/sprig/v3"
+	"github.com/clevyr/yampl/internal/util"
 )
 
 func FuncMap() template.FuncMap {
 	fmap := sprig.TxtFuncMap()
-	for k, v := range fmap {
-		if strings.HasPrefix(k, "must") {
-			k := strings.TrimPrefix(k, "must")
-			k = strings.ToLower(k[0:1]) + k[1:]
-			fmap[k] = v
+	// Prefix functions with "may" that have a "must" counterpart
+	for key, fn := range fmap {
+		if !strings.HasPrefix(key, "must") {
+			mustKey := "must" + util.UpperFirst(key)
+			if _, ok := fmap[mustKey]; ok {
+				key = "may" + util.UpperFirst(key)
+				fmap[key] = fn
+			}
+		}
+	}
+	// Remove prefix from "must" functions
+	for key, fn := range fmap {
+		if strings.HasPrefix(key, "must") {
+			k := strings.TrimPrefix(key, "must")
+			k = util.LowerFirst(k)
+			fmap[k] = fn
 		}
 	}
 	fmap["repo"] = DockerRepo

internal/util/strings.go

@@ -0,0 +1,25 @@
+package util
+
+import "strings"
+
+func UpperFirst(s string) string {
+	switch len(s) {
+	case 0:
+		return s
+	case 1:
+		return strings.ToUpper(s)
+	default:
+		return strings.ToUpper(s[0:1]) + s[1:]
+	}
+}
+
+func LowerFirst(s string) string {
+	switch len(s) {
+	case 0:
+		return s
+	case 1:
+		return strings.ToLower(s)
+	default:
+		return strings.ToLower(s[0:1]) + s[1:]
+	}
+}

internal/util/strings_test.go

@@ -0,0 +1,47 @@
+package util
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLowerFirst(t *testing.T) {
+	type args struct {
+		s string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{"empty", args{""}, ""},
+		{"len 1", args{"A"}, "a"},
+		{"multiple", args{"TestArg"}, "testArg"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equalf(t, tt.want, LowerFirst(tt.args.s), "LowerFirst(%v)", tt.args.s)
+		})
+	}
+}
+
+func TestUpperFirst(t *testing.T) {
+	type args struct {
+		s string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{"empty", args{""}, ""},
+		{"len 1", args{"a"}, "A"},
+		{"multiple", args{"testArg"}, "TestArg"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equalf(t, tt.want, UpperFirst(tt.args.s), "UpperFirst(%v)", tt.args.s)
+		})
+	}
+}