Info Catalog eieio: Initialization eieio: Default Superclass eieio: Signal Handling

eieio: Basic Methods

 
 15.2 Basic Methods
 ==================
 
 Additional useful methods defined on the base subclass are:
 
  -- Function: clone obj &rest params
      Make a copy of OBJ, and then apply PARAMS.  PARAMS is a parameter
      list of the same form as INITIALIZE-INSTANCE which are applied to
      change the object.  When overloading “clone”, be sure to call
      “call-next-method” first and modify the returned object.
 
  -- Function: object-print this &rest strings
      Pretty printer for object THIS.  Call function “eieio-object-name”
      with STRINGS.  The default method for printing object THIS is to
      use the function “eieio-object-name”.
 
      It is sometimes useful to put a summary of the object into the
      default #<notation> string when using eieio browsing tools.
 
      Implement this function and specify STRINGS in a call to
      “call-next-method” to provide additional summary information.  When
      passing in extra strings from child classes, always remember to
      prepend a space.
 
           (defclass data-object ()
              (value)
              "Object containing one data slot.")
 
           (defmethod object-print ((this data-object) &optional strings)
             "Return a string with a summary of the data object as part of the name."
             (apply 'call-next-method this
                    (cons (format " value: %s" (render this)) strings)))
 
      Here is what some output could look like:
           (object-print test-object)
              => #<data-object test-object value: 3>
 
  -- Function: object-write obj &optional comment
      Write OBJ onto a stream in a readable fashion.  The resulting
      output will be Lisp code which can be used with ‘read’ and ‘eval’
      to recover the object.  Only slots with ‘:initarg’s are written to
      the stream.
 

Info Catalog eieio: Initialization eieio: Default Superclass eieio: Signal Handling