- (or (stringp (aref menuitem 0))
- (signal 'error
- (list
- "first element of a button must be a string (the label)"
- menuitem)))
- (or plistp
- (< L 4)
- (null (aref menuitem 3))
- (stringp (aref menuitem 3))
- (signal 'error
- (list
- "fourth element of a button must be a string (the label suffix)"
- menuitem)))