;;; eieio-compat.el --- Compatibility with Older EIEIO versions -*- lexical-binding:t -*-
;; Copyright (C) 1995-1996, 1998-2019 Free Software Foundation, Inc.
;; Author: Eric M. Ludlam <zappo@gnu.org>
;; Keywords: OO, lisp
;; Package: eieio
;; This file is part of GNU Emacs.
;; GNU Emacs 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 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs 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. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Backward compatibility definition of old EIEIO functions in
;; terms of newer equivalent.
;; The main elements are the old EIEIO `defmethod' and `defgeneric' which are
;; now implemented on top of cl-generic. The differences we have to
;; accommodate are:
;; - EIEIO's :static methods (turned into a new `eieio--static' specializer).
;; - EIEIO's support for `call-next-method' and `next-method-p' instead of
;; `cl-next-method-p' and `cl-call-next-method' (simple matter of renaming).
;; - Different errors are signaled.
;; - EIEIO's defgeneric does not reset the function.
;; - EIEIO's no-next-method and no-applicable-method can't be aliases of
;; cl-generic's namesakes since they have different calling conventions,
;; which means that packages that (defmethod no-next-method ..) don't work.
;; - EIEIO's `call-next-method' and `next-method-p' had dynamic scope whereas
;; cl-generic's `cl-next-method-p' and `cl-call-next-method' are lexically
;; scoped.
;;; Code:
(require 'eieio-core)
(require 'cl-generic)
(put 'eieio--defalias 'byte-hunk-handler
#'byte-compile-file-form-defalias) ;;(get 'defalias 'byte-hunk-handler)
;;;###autoload
(defun eieio--defalias (name body)
"Like `defalias', but with less side-effects.
More specifically, it has no side-effects at all when the new function
definition is the same (`eq') as the old one."
(cl-assert (not (symbolp body)))
(while (and (fboundp name) (symbolp (symbol-function name)))
;; Follow aliases, so methods applied to obsolete aliases still work.
(setq name (symbol-function name)))
(unless (and (fboundp name)
(eq (symbol-function name) body))
(defalias name body)))
;;;###autoload
(defmacro defgeneric (method args &optional doc-string)
"Create a generic function METHOD.
DOC-STRING is the base documentation for this class. A generic
function has no body, as its purpose is to decide which method body
is appropriate to use. Uses `defmethod' to create methods, and calls
`defgeneric' for you. With this implementation the ARGS are
currently ignored. You can use `defgeneric' to apply specialized
top level documentation to a method."
(declare (doc-string 3) (obsolete cl-defgeneric "25.1"))
`(eieio--defalias ',method
(eieio--defgeneric-init-form
',method
,(if doc-string (help-add-fundoc-usage doc-string args)))))
;;;###autoload
(defmacro defmethod (method &rest args)
"Create a new METHOD through `defgeneric' with ARGS.
The optional second argument KEY is a specifier that
modifies how the method is called, including:
:before - Method will be called before the :primary
:primary - The default if not specified
:after - Method will be called after the :primary
:static - First arg could be an object or class
The next argument is the ARGLIST. The ARGLIST specifies the arguments
to the method as with `defun'. The first argument can have a type
specifier, such as:
((VARNAME CLASS) ARG2 ...)
where VARNAME is the name of the local variable for the method being
created. The CLASS is a class symbol for a class made with `defclass'.
A DOCSTRING comes after the ARGLIST, and is optional.
All the rest of the args are the BODY of the method. A method will
return the value of the last form in the BODY.
Summary:
(defmethod mymethod [:before | :primary | :after | :static]
((typearg class-name) arg2 &optional opt &rest rest)
\"doc-string\"
body)"
(declare (doc-string 3) (obsolete cl-defmethod "25.1")
(debug
(&define ; this means we are defining something
[&or name ("setf" name :name setf)]
;; ^^ This is the methods symbol
[ &optional symbolp ] ; this is key :before etc
cl-generic-method-args ; arguments
[ &optional stringp ] ; documentation string
def-body ; part to be debugged
)))
(let* ((key (if (keywordp (car args)) (pop args)))
(params (car args))
(arg1 (car params))
(fargs (if (consp arg1)
(cons (car arg1) (cdr params))
params))
(class (if (consp arg1) (nth 1 arg1)))
(code `(lambda ,fargs ,@(cdr args))))
`(progn
;; Make sure there is a generic and the byte-compiler sees it.
(defgeneric ,method ,args)
(eieio--defmethod ',method ',key ',class #',code))))
(defun eieio--generic-static-symbol-specializers (tag &rest _)
(cl-assert (or (null tag) (eieio--class-p tag)))
(when (eieio--class-p tag)
(let ((superclasses (eieio--generic-subclass-specializers tag))
(specializers ()))
(dolist (superclass superclasses)
(push superclass specializers)
(push `(eieio--static ,(cadr superclass)) specializers))
(nreverse specializers))))
(cl-generic-define-generalizer eieio--generic-static-symbol-generalizer
;; Give it a slightly higher priority than `subclass' so that the
;; interleaved list comes before subclass's non-interleaved list.
61 (lambda (name &rest _) `(and (symbolp ,name) (cl--find-class ,name)))
#'eieio--generic-static-symbol-specializers)
(cl-generic-define-generalizer eieio--generic-static-object-generalizer
;; Give it a slightly higher priority than `class' so that the
;; interleaved list comes before the class's non-interleaved list.
51 #'cl--generic-struct-tag
(lambda (tag &rest _)
(and (symbolp tag) (setq tag (cl--find-class tag))
(eieio--class-p tag)
(let ((superclasses (eieio--class-precedence-list tag))
(specializers ()))
(dolist (superclass superclasses)
(setq superclass (eieio--class-name superclass))
(push superclass specializers)
(push `(eieio--static ,superclass) specializers))
(nreverse specializers)))))
(cl-defmethod cl-generic-generalizers ((_specializer (head eieio--static)))
(list eieio--generic-static-symbol-generalizer
eieio--generic-static-object-generalizer))
;;;###autoload
(defun eieio--defgeneric-init-form (method doc-string)
(if doc-string (put method 'function-documentation doc-string))
(if (memq method '(no-next-method no-applicable-method))
(symbol-function method)
(let ((generic (cl-generic-ensure-function method)))
(or (symbol-function (cl--generic-name generic))
(cl--generic-make-function generic)))))
;;;###autoload
(defun eieio--defmethod (method kind argclass code)
(setq kind (intern (downcase (symbol-name kind))))
(let* ((specializer (if (not (eq kind :static))
(or argclass t)
(setq kind nil)
`(eieio--static ,argclass)))
(uses-cnm (not (memq kind '(:before :after))))
(specializers `((arg ,specializer)))
(code
;; Backward compatibility for `no-next-method' and
;; `no-applicable-method', which have slightly different calling
;; convention than their cl-generic counterpart.
(pcase method
('no-next-method
(setq method 'cl-no-next-method)
(setq specializers `(generic method ,@specializers))
(lambda (_generic _method &rest args) (apply code args)))
('no-applicable-method
(setq method 'cl-no-applicable-method)
(setq specializers `(generic ,@specializers))
(lambda (generic arg &rest args)
(apply code arg (cl--generic-name generic) (cons arg args))))
(_ code))))
(cl-generic-define-method
method (unless (memq kind '(nil :primary)) (list kind))
specializers uses-cnm
(if uses-cnm
(let* ((docstring (documentation code 'raw))
(args (help-function-arglist code 'preserve-names))
(doc-only (if docstring
(let ((split (help-split-fundoc docstring nil)))
(if split (cdr split) docstring)))))
(lambda (cnm &rest args)
(:documentation
(help-add-fundoc-usage doc-only (cons 'cl-cnm args)))
(cl-letf (((symbol-function 'call-next-method) cnm)
((symbol-function 'next-method-p)
(lambda () (cl--generic-isnot-nnm-p cnm))))
(apply code args))))
code))
;; The old EIEIO code did not signal an error when there are methods
;; applicable but only of the before/after kind. So if we add a :before
;; or :after, make sure there's a matching dummy primary.
(when (and (memq kind '(:before :after))
;; FIXME: Use `cl-find-method'?
(not (cl-find-method method ()
(mapcar (lambda (arg)
(if (consp arg) (nth 1 arg) t))
specializers))))
(cl-generic-define-method method () specializers t
(lambda (cnm &rest args)
(if (cl--generic-isnot-nnm-p cnm)
(apply cnm args)))))
method))
;; Compatibility with code which tries to catch `no-method-definition' errors.
(push 'no-method-definition (get 'cl-no-applicable-method 'error-conditions))
(defun generic-p (fname) (not (null (cl--generic fname))))
(defun no-next-method (&rest args)
(declare (obsolete cl-no-next-method "25.1"))
(apply #'cl-no-next-method 'unknown nil args))
(defun no-applicable-method (object method &rest args)
(declare (obsolete cl-no-applicable-method "25.1"))
(apply #'cl-no-applicable-method method object args))
(define-obsolete-function-alias 'call-next-method 'cl-call-next-method "25.1")
(defun next-method-p ()
(declare (obsolete cl-next-method-p "25.1"))
;; EIEIO's `next-method-p' just returned nil when called in an
;; invalid context.
(message "next-method-p called outside of a primary or around method")
nil)
;;;###autoload
(defun eieio-defmethod (method args)
"Obsolete work part of an old version of the `defmethod' macro."
(declare (obsolete cl-defmethod "24.1"))
(eval `(defmethod ,method ,@args))
method)
;;;###autoload
(defun eieio-defgeneric (method doc-string)
"Obsolete work part of an old version of the `defgeneric' macro."
(declare (obsolete cl-defgeneric "24.1"))
(eval `(defgeneric ,method (x) ,@(if doc-string `(,doc-string))))
;; Return the method
'method)
;;;###autoload
(defun eieio-defclass (cname superclasses slots options)
(declare (obsolete eieio-defclass-internal "25.1"))
(eval `(defclass ,cname ,superclasses ,slots ,@options)))
;; Local Variables:
;; generated-autoload-file: "eieio-loaddefs.el"
;; End:
(provide 'eieio-compat)
;;; eieio-compat.el ends here