package resource import ( "context" "fmt" "log" ) // EntryFunc is a function signature for retrieving value for a key type EntryFunc func(ctx context.Context) (string, error) // Resource implementation are responsible for retrieving values and templates for symbols, and can render templates from value dictionaries. type Resource interface { GetTemplate(sym string) (string, error) // Get the template for a given symbol. GetCode(sym string) ([]byte, error) // Get the bytecode for the given symbol. PutMenu(string, string) error // Add a menu item. ShiftMenu() (string, string, error) // Remove and return the first menu item in list. SetMenuBrowse(string, string, bool) error // Set menu browser display details. RenderTemplate(sym string, values map[string]string) (string, error) // Render the given data map using the template of the symbol. RenderMenu() (string, error) FuncFor(sym string) (EntryFunc, error) // Resolve symbol code point for. } type MenuResource struct { menu [][2]string next [2]string prev [2]string } func(m *MenuResource) SetMenuBrowse(selector string, title string, back bool) error { entry := [2]string{selector, title} if back { m.prev = entry } else { m.next = entry } return nil } func(m *MenuResource) PutMenu(selector string, title string) error { m.menu = append(m.menu, [2]string{selector, title}) log.Printf("menu %v", m.menu) return nil } func(m *MenuResource) ShiftMenu() (string, string, error) { if len(m.menu) == 0 { return "", "", fmt.Errorf("menu is empty") } r := m.menu[0] m.menu = m.menu[1:] return r[0], r[1], nil } func(m *MenuResource) RenderMenu() (string, error) { r := "" for true { l := len(r) choice, title, err := m.ShiftMenu() if err != nil { break } if l > 0 { r += "\n" } r += fmt.Sprintf("%s:%s", choice, title) } return r, nil }