Handle() now supports keyboard buttons as endpoints.

bot.go

@@ -94,6 +94,8 @@ func (b *Bot) Handle(endpoint interface{}, handler interface{}) {
 		b.handlers[end] = handler
 	case CallbackEndpoint:
 		b.handlers["\f"+end.CallbackUnique()] = handler
+	default:
+		panic("telebot: unsupported endpoint")
 	}
 }
 
@@ -380,7 +382,7 @@ func (b *Bot) Send(to Recipient, what interface{}, options ...interface{}) (*Mes
 	case Sendable:
 		return object.Send(b, to, sendOpts)
 	default:
-		panic(fmt.Sprintf("telebot: object %v is not Sendable", object))
+		panic("telebot: unsupported sendable")
 	}
 }
 

callbacks.go

@@ -68,7 +68,12 @@ type InlineButton struct {
 	InlineQuery string `json:"switch_inline_query,omitempty"`
 }
 
-// CallbackUnique returns InlineButto.Unique
+// CallbackUnique returns InlineButto.Unique.
 func (t *InlineButton) CallbackUnique() string {
 	return t.Unique
 }
+
+// CallbackUnique returns KeyboardButton.Text.
+func (t *KeyboardButton) CallbackUnique() string {
+	return t.Text
+}

options.go

@@ -91,7 +91,7 @@ type ReplyMarkup struct {
 //
 // Set either Contact or Location to true in order to request
 // sensitive info, such as user's phone number or current location.
-// (Available in private chats only)
+// (Available in private chats only.)
 type KeyboardButton struct {
 	Text string `json:"text"`
 

util.go

@@ -2,7 +2,6 @@ package telebot
 
 import (
 	"encoding/json"
-	"fmt"
 	"strconv"
 
 	"github.com/pkg/errors"
@@ -125,7 +124,7 @@ func extractOptions(how []interface{}) *SendOptions {
 			opts.ParseMode = opt
 
 		default:
-			panic(fmt.Sprintf("telebot: %v is not a send-option", opt))
+			panic("telebot: unsupported send-option")
 		}
 	}
 
@@ -160,6 +159,7 @@ func embedSendOptions(params map[string]string, opt *SendOptions) {
 				for j, _ := range keys[i] {
 					key := &keys[i][j]
 					if key.Unique != "" {
+						// Format: "\f<callback_name>|<data>"
 						key.Data = "\f" + key.Unique + "|" + key.Data
 					}
 				}