Added a Printable method to button

examples/type/main.go

@@ -38,10 +38,14 @@ func main () {
 			os.Exit(0)
 
 		case stone.EventPress:
-			event := event.(stone.EventPress)
-			if stone.event.Printable() {
-				application.SetRune(caret, 0, rune(stone.event))
+			button := stone.Button(event.(stone.EventPress))
+			if button.Printable() {
+				application.SetRune(caret, 0, rune(button))
 				caret ++
+				width, _ := application.Size()
+				if caret >= width {
+					caret = 0
+				}
 				application.Draw()
 			}
 

input.go

@@ -1,5 +1,7 @@
 package stone
 
+import "unicode"
+
 type Button int
 
 const (
@@ -69,3 +71,8 @@ const (
 	KeyF11 Button = 154
 	KeyF12 Button = 155
 )
+
+func (button Button) Printable () (printable bool) {
+	printable = unicode.IsPrint(rune(button))
+	return
+}