+;;; luna.el --- tiny OOP system kernel
+
+;; Copyright (C) 1999,2000,2002 Free Software Foundation, Inc.
+
+;; Author: MORIOKA Tomohiko <tomo@m17n.org>
+;; Keywords: OOP
+
+;; This file is part of FLIM (Faithful Library about Internet Message).
+
+;; This program is free software; you can redistribute it and/or
+;; modify it under the terms of the GNU General Public License as
+;; published by the Free Software Foundation; either version 2, or (at
+;; your option) any later version.
+
+;; This program is distributed in the hope that it will be useful, but
+;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+;; General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING. If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Code:
+
+(eval-when-compile (require 'cl))
+
+
+;;; @ class
+;;;
+
+(defmacro luna-find-class (name)
+ "Return a luna-class that has NAME."
+ `(get ,name 'luna-class))
+
+;; Give NAME (symbol) the luna-class CLASS.
+(defmacro luna-set-class (name class)
+ `(put ,name 'luna-class ,class))
+
+;; Return the obarray of luna-class CLASS.
+(defmacro luna-class-obarray (class)
+ `(aref ,class 1))
+
+;; Return the parents of luna-class CLASS.
+(defmacro luna-class-parents (class)
+ `(aref ,class 2))
+
+;; Return the number of slots of luna-class CLASS.
+(defmacro luna-class-number-of-slots (class)
+ `(aref ,class 3))
+
+(defmacro luna-define-class (class &optional parents slots)
+ "Define CLASS as a luna-class.
+CLASS always inherits the luna-class `standard-object'.
+
+The optional 1st arg PARENTS is a list luna-class names. These
+luna-classes are also inheritted by CLASS.
+
+The optional 2nd arg SLOTS is a list of slots CLASS will have."
+ `(luna-define-class-function ',class ',(append parents '(standard-object))
+ ',slots))
+
+
+;; Define CLASS as a luna-class. PARENTS, if non-nil, is a list of
+;; luna-class names inherited by CLASS. SLOTS, if non-nil, is a list
+;; of slots belonging to CLASS.
+
+(defun luna-define-class-function (class &optional parents slots)
+ (let ((oa (make-vector 31 0))
+ (rest parents)
+ parent name
+ (i 2)
+ b j)
+ (while rest
+ (setq parent (pop rest)
+ b (- i 2))
+ (mapatoms (lambda (sym)
+ (when (setq j (get sym 'luna-slot-index))
+ (setq name (symbol-name sym))
+ (unless (intern-soft name oa)
+ (put (intern name oa) 'luna-slot-index (+ j b))
+ (setq i (1+ i)))))
+ (luna-class-obarray (luna-find-class parent))))
+ (setq rest slots)
+ (while rest
+ (setq name (symbol-name (pop rest)))
+ (unless (intern-soft name oa)
+ (put (intern name oa) 'luna-slot-index i)
+ (setq i (1+ i))))
+ (luna-set-class class (vector 'class oa parents i))))
+
+
+;; Return a member (slot or method) of CLASS that has name
+;; MEMBER-NAME.
+
+(defun luna-class-find-member (class member-name)
+ (or (stringp member-name)
+ (setq member-name (symbol-name member-name)))
+ (intern-soft member-name (luna-class-obarray class)))
+
+
+;; Return a member (slot or method) of CLASS that has name
+;; MEMBER-NAME. If CLASS doesnt' have such a member, make it in
+;; CLASS.
+
+(defsubst luna-class-find-or-make-member (class member-name)
+ (or (stringp member-name)
+ (setq member-name (symbol-name member-name)))
+ (intern member-name (luna-class-obarray class)))
+
+
+;; Return the index number of SLOT-NAME in CLASS.
+
+(defmacro luna-class-slot-index (class slot-name)
+ `(get (luna-class-find-member ,class ,slot-name) 'luna-slot-index))
+
+(defmacro luna-define-method (name &rest definition)
+ "Define NAME as a method of a luna class.
+
+Usage of this macro follows:
+
+ (luna-define-method NAME [METHOD-QUALIFIER] ARGLIST [DOCSTRING] BODY...)
+
+The optional 1st argument METHOD-QUALIFIER specifies when and how the
+method is called.
+
+If it is :before, call the method before calling the parents' methods.
+
+If it is :after, call the method after calling the parents' methods.
+
+If it is :around, call the method only. The parents' methods can be
+executed by calling the function `luna-call-next-method' in BODY.
+
+Otherwize, call the method only, and the parents' methods are never
+executed. In this case, METHOD-QUALIFIER is treated as ARGLIST.
+
+ARGLIST has the form ((VAR CLASS) METHOD-ARG ...), where VAR is a
+variable name that should be bound to an entity that receives the
+message NAME, CLASS is a class name. The first argument to the method
+is VAR, and the remaining arguments are METHOD-ARGs.
+
+If VAR is nil, arguments to the method are METHOD-ARGs. This kind of
+methods can't be called from generic-function (see
+`luna-define-generic').
+
+The optional 4th argument DOCSTRING is the documentation of the
+method. If it is not string, it is treated as BODY.
+
+The optional 5th BODY is the body of the method."
+ (let ((method-qualifier (pop definition))
+ args specializer class self)
+ (if (memq method-qualifier '(:before :after :around))
+ (setq args (pop definition))
+ (setq args method-qualifier
+ method-qualifier nil))
+ (setq specializer (car args)
+ class (nth 1 specializer)
+ self (car specializer))
+ `(let ((func (lambda ,(if self
+ (cons self (cdr args))
+ (cdr args))
+ ,@definition))
+ (sym (luna-class-find-or-make-member
+ (luna-find-class ',class) ',name))
+ (cache (get ',name 'luna-method-cache)))
+ (and cache
+ (fboundp sym)
+ (mapatoms
+ (lambda (s)
+ (if (memq (symbol-function sym) (symbol-value s))
+ (unintern s cache)))
+ cache))
+ (fset sym func)
+ (put sym 'luna-method-qualifier ,method-qualifier))))
+
+(put 'luna-define-method 'lisp-indent-function 'defun)
+
+(def-edebug-spec luna-define-method
+ (&define name [&optional &or ":before" ":after" ":around"]
+ ((arg symbolp)
+ [&rest arg]
+ [&optional ["&optional" arg &rest arg]]
+ &optional ["&rest" arg])
+ def-body))
+
+
+;; Return a list of method functions named SERVICE registered in the
+;; parents of CLASS.
+
+(defun luna-class-find-parents-functions (class service)
+ (let ((parents (luna-class-parents class))
+ ret)
+ (while (and parents
+ (null
+ (setq ret (luna-class-find-functions
+ (luna-find-class (pop parents))
+ service)))))
+ ret))
+
+;; Return a list of method functions named SERVICE registered in CLASS
+;; and the parents..
+
+(defun luna-class-find-functions (class service)
+ (let ((sym (luna-class-find-member class service)))
+ (if (fboundp sym)
+ (cond ((eq (get sym 'luna-method-qualifier) :before)
+ (cons (symbol-function sym)
+ (luna-class-find-parents-functions class service)))
+ ((eq (get sym 'luna-method-qualifier) :after)
+ (nconc (luna-class-find-parents-functions class service)
+ (list (symbol-function sym))))
+ ((eq (get sym 'luna-method-qualifier) :around)
+ (cons sym (luna-class-find-parents-functions class service)))
+ (t
+ (list (symbol-function sym))))
+ (luna-class-find-parents-functions class service))))
+
+
+;;; @ instance (entity)
+;;;
+
+(defmacro luna-class-name (entity)
+ "Return class-name of the ENTITY."
+ `(aref ,entity 0))
+
+(defmacro luna-set-class-name (entity name)
+ `(aset ,entity 0 ,name))
+
+(defmacro luna-get-obarray (entity)
+ `(aref ,entity 1))
+
+(defmacro luna-set-obarray (entity obarray)
+ `(aset ,entity 1 ,obarray))
+
+(defmacro luna-slot-index (entity slot-name)
+ `(luna-class-slot-index (luna-find-class (luna-class-name ,entity))
+ ,slot-name))
+
+(defsubst luna-slot-value (entity slot)
+ "Return the value of SLOT of ENTITY."
+ (aref entity (luna-slot-index entity slot)))
+
+(defsubst luna-set-slot-value (entity slot value)
+ "Store VALUE into SLOT of ENTITY."
+ (aset entity (luna-slot-index entity slot) value))
+
+(defmacro luna-find-functions (entity service)
+ `(luna-class-find-functions (luna-find-class (luna-class-name ,entity))
+ ,service))
+
+(defsubst luna-send (entity message &rest luna-current-method-arguments)
+ "Send MESSAGE to ENTITY, and return the result.
+ENTITY is an instance of a luna class, and MESSAGE is a method name of
+the luna class.
+LUNA-CURRENT-METHOD-ARGUMENTS is arguments of the MESSAGE."
+ (let ((luna-next-methods (luna-find-functions entity message))
+ luna-current-method
+ luna-previous-return-value)
+ (while (and luna-next-methods
+ (progn
+ (setq luna-current-method (pop luna-next-methods)
+ luna-previous-return-value
+ (apply luna-current-method
+ luna-current-method-arguments))
+ (if (symbolp luna-current-method)
+ (not (eq (get luna-current-method
+ 'luna-method-qualifier) :around))
+ t))))
+ luna-previous-return-value))
+
+(eval-when-compile
+ (defvar luna-next-methods nil)
+ (defvar luna-current-method-arguments nil))
+
+(defun luna-call-next-method ()
+ "Call the next method in the current method function.
+A method function that has :around qualifier should call this function
+to execute the parents' methods."
+ (let (luna-current-method
+ luna-previous-return-value)
+ (while (and luna-next-methods
+ (progn
+ (setq luna-current-method (pop luna-next-methods)
+ luna-previous-return-value
+ (apply luna-current-method
+ luna-current-method-arguments))
+ (if (symbolp luna-current-method)
+ (not (eq (get luna-current-method
+ 'luna-method-qualifier) :around))
+ t))))
+ luna-previous-return-value))
+
+(defun luna-make-entity (class &rest init-args)
+ "Make an entity (instance) of luna-class CLASS and return it.
+INIT-ARGS is a plist of the form (:SLOT1 VAL1 :SLOT2 VAL2 ...),
+where SLOTs are slots of CLASS and the VALs are initial values of
+the corresponding SLOTs."
+ (let* ((c (get class 'luna-class))
+ (v (make-vector (luna-class-number-of-slots c) nil)))
+ (luna-set-class-name v class)
+ (luna-set-obarray v (make-vector 7 0))
+ (apply #'luna-send v 'initialize-instance v init-args)))
+
+
+;;; @ interface (generic function)
+;;;
+
+;; Find a method of ENTITY that handles MESSAGE, and call it with
+;; arguments LUNA-CURRENT-METHOD-ARGUMENTS.
+
+(defun luna-apply-generic (entity message &rest luna-current-method-arguments)
+ (let* ((class (luna-class-name entity))
+ (cache (get message 'luna-method-cache))
+ (sym (intern-soft (symbol-name class) cache))
+ luna-next-methods)
+ (if sym
+ (setq luna-next-methods (symbol-value sym))
+ (setq luna-next-methods
+ (luna-find-functions entity message))
+ (set (intern (symbol-name class) cache)
+ luna-next-methods))
+ (luna-call-next-method)))
+
+
+;; Convert ARGLIST (argument list spec for a method function) to the
+;; actual list of arguments.
+
+(defsubst luna-arglist-to-arguments (arglist)
+ (let (dest)
+ (while arglist
+ (let ((arg (car arglist)))
+ (or (memq arg '(&optional &rest))
+ (setq dest (cons arg dest))))
+ (setq arglist (cdr arglist)))
+ (nreverse dest)))
+
+
+(defmacro luna-define-generic (name args &optional doc)
+ "Define a function NAME that provides a generic interface to the method NAME.
+ARGS is the argument list for NAME. The first element of ARGS is an
+entity.
+
+The function handles a message sent to the entity by calling the
+method with proper arguments.
+
+The optional 3rd argument DOC is the documentation string for NAME."
+ (if doc
+ `(progn
+ (defun ,(intern (symbol-name name)) ,args
+ ,doc
+ (luna-apply-generic ,(car args) ',name
+ ,@(luna-arglist-to-arguments args)))
+ (put ',name 'luna-method-cache (make-vector 31 0)))
+ `(progn
+ (defun ,(intern (symbol-name name)) ,args
+ (luna-apply-generic ,(car args) ',name
+ ,@(luna-arglist-to-arguments args)))
+ (put ',name 'luna-method-cache (make-vector 31 0)))))
+
+(put 'luna-define-generic 'lisp-indent-function 'defun)
+
+
+;;; @ accessor
+;;;
+
+(defun luna-define-internal-accessors (class-name)
+ "Define internal accessors for instances of the luna class CLASS-NAME.
+
+Internal accessors are macros to refer and set a slot value of the
+instances. For instance, if the class has SLOT, macros
+CLASS-NAME-SLOT-internal and CLASS-NAME-set-SLOT-internal are defined.
+
+CLASS-NAME-SLOT-internal accepts one argument INSTANCE, and returns
+the value of SLOT.
+
+CLASS-NAME-set-SLOT-internal accepts two arguemnt INSTANCE and VALUE,
+and sets SLOT to VALUE."
+ (let ((entity-class (luna-find-class class-name))
+ parents parent-class)
+ (mapatoms
+ (lambda (slot)
+ (if (luna-class-slot-index entity-class slot)
+ (catch 'derived
+ (setq parents (luna-class-parents entity-class))
+ (while parents
+ (setq parent-class (luna-find-class (car parents)))
+ (if (luna-class-slot-index parent-class slot)
+ (throw 'derived nil))
+ (setq parents (cdr parents)))
+ (eval
+ `(progn
+ (defmacro ,(intern (format "%s-%s-internal"
+ class-name slot))
+ (entity)
+ (list 'aref entity
+ ,(luna-class-slot-index entity-class
+ (intern (symbol-name slot)))))
+ (defmacro ,(intern (format "%s-set-%s-internal"
+ class-name slot))
+ (entity value)
+ (list 'aset entity
+ ,(luna-class-slot-index
+ entity-class (intern (symbol-name slot)))
+ value)))))))
+ (luna-class-obarray entity-class))))
+
+
+;;; @ standard object
+;;;
+
+;; Define super class of all luna classes.
+(luna-define-class-function 'standard-object)
+
+(luna-define-method initialize-instance ((entity standard-object)
+ &rest init-args)
+ "Initialize slots of ENTITY by INIT-ARGS."
+ (let* ((c (luna-find-class (luna-class-name entity)))
+ (oa (luna-class-obarray c))
+ s i)
+ (while init-args
+ (setq s (intern-soft (substring (symbol-name (pop init-args)) 1) oa)
+ i (pop init-args))
+ (if s
+ (aset entity (get s 'luna-slot-index) i)))
+ entity))
+
+
+;;; @ end
+;;;
+
+(provide 'luna)
+
+;; luna.el ends here
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