add suffix support to generate endpoint

this change is triggered by the presence of "suffix", particularly
useful for code completion tasks

template/template.go

@@ -151,6 +151,8 @@ func (t *Template) Vars() []string {
 type Values struct {
 	Messages []api.Message
 	Tools    []api.Tool
+	Prompt   string
+	Suffix   string
 
 	// forceLegacy is a flag used to test compatibility with legacy templates
 	forceLegacy bool
@@ -204,7 +206,13 @@ func (t *Template) Subtree(fn func(parse.Node) bool) *template.Template {
 
 func (t *Template) Execute(w io.Writer, v Values) error {
 	system, messages := collate(v.Messages)
-	if !v.forceLegacy && slices.Contains(t.Vars(), "messages") {
+	if v.Prompt != "" && v.Suffix != "" {
+		return t.Template.Execute(w, map[string]any{
+			"Prompt":   v.Prompt,
+			"Suffix":   v.Suffix,
+			"Response": "",
+		})
+	} else if !v.forceLegacy && slices.Contains(t.Vars(), "messages") {
 		return t.Template.Execute(w, map[string]any{
 			"System":   system,
 			"Messages": messages,