mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-12-05 08:53:45 +00:00
4d449b11a0
Add lisp/emacs-lisp/macroexp.el
198 lines
7.2 KiB
EmacsLisp
198 lines
7.2 KiB
EmacsLisp
;;; macroexp.el --- Additional macro-expansion support
|
|
;;
|
|
;; Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
|
|
;;
|
|
;; Author: Miles Bader <miles@gnu.org>
|
|
;; Keywords: lisp, compiler, macros
|
|
|
|
;; 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 2, 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; see the file COPYING. If not, write to the
|
|
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
;; Boston, MA 02111-1307, USA.
|
|
|
|
;;; Commentary:
|
|
;;
|
|
;; This file contains macro-expansions functions that are not defined in
|
|
;; the Lisp core, namely `macroexpand-all', which expands all macros in
|
|
;; a form, not just a top-level one.
|
|
;;
|
|
|
|
;;; Code:
|
|
|
|
;; Bound by the top-level `macroexpand-all', and modified to include any
|
|
;; macros defined by `defmacro'.
|
|
(defvar macroexpand-all-environment nil)
|
|
|
|
(defun maybe-cons (car cdr original-cons)
|
|
"Return (CAR . CDR), using ORIGINAL-CONS if possible."
|
|
(if (and (eq car (car original-cons)) (eq cdr (cdr original-cons)))
|
|
original-cons
|
|
(cons car cdr)))
|
|
|
|
;; We use this special macro to iteratively process forms and share list
|
|
;; structure of the result with the input. Doing so recursively using
|
|
;; `maybe-cons' results in excessively deep recursion for very long
|
|
;; input forms.
|
|
(defmacro macroexp-accumulate (#1=#:\(var\ list\) &rest body)
|
|
"Return a list of the results of evaluating BODY for each element of LIST.
|
|
Evaluate BODY with VAR bound to each `car' from LIST, in turn.
|
|
Return a list of the values of the final form in BODY.
|
|
The list structure of the result will share as much with LIST as
|
|
possible (for instance, when BODY just returns VAR unchanged, the
|
|
result will be eq to LIST)."
|
|
(let ((var (car #1#))
|
|
(list (cadr #1#))
|
|
(shared (make-symbol "shared"))
|
|
(unshared (make-symbol "unshared"))
|
|
(tail (make-symbol "tail"))
|
|
(new-el (make-symbol "new-el")))
|
|
`(let* ((,shared ,list)
|
|
(,unshared nil)
|
|
(,tail ,shared)
|
|
,var ,new-el)
|
|
(while ,tail
|
|
(setq ,var (car ,tail)
|
|
,new-el (progn ,@body))
|
|
(unless (eq ,var ,new-el)
|
|
(while (not (eq ,shared ,tail))
|
|
(push (pop ,shared) ,unshared))
|
|
(setq ,shared (cdr ,shared))
|
|
(push ,new-el ,unshared))
|
|
(setq ,tail (cdr ,tail)))
|
|
(nconc (nreverse ,unshared) ,shared))))
|
|
(put 'macroexp-accumulate 'lisp-indent-function 1)
|
|
|
|
(defun macroexpand-all-forms (forms &optional skip)
|
|
"Return FORMS with macros expanded. FORMS is a list of forms.
|
|
If SKIP is non-nil, then don't expand that many elements at the start of
|
|
FORMS."
|
|
(macroexp-accumulate (form forms)
|
|
(if (or (null skip) (zerop skip))
|
|
(macroexpand-all-1 form)
|
|
(setq skip (1- skip))
|
|
form)))
|
|
|
|
(defun macroexpand-all-clauses (clauses &optional skip)
|
|
"Return CLAUSES with macros expanded.
|
|
CLAUSES is a list of lists of forms; any clause that's not a list is ignored.
|
|
If SKIP is non-nil, then don't expand that many elements at the start of
|
|
each clause."
|
|
(macroexp-accumulate (clause clauses)
|
|
(if (listp clause)
|
|
(macroexpand-all-forms clause skip)
|
|
clause)))
|
|
|
|
(defun macroexpand-all-1 (form)
|
|
"Expand all macros in FORM.
|
|
This is an internal version of `macroexpand-all'.
|
|
Assumes the caller has bound `macroexpand-all-environment'."
|
|
(if (and (listp form) (eq (car form) 'backquote-list*))
|
|
;; Special-case `backquote-list*', as it is normally a macro that
|
|
;; generates exceedingly deep expansions from relatively shallow input
|
|
;; forms. We just process it `in reverse' -- first we expand all the
|
|
;; arguments, _then_ we expand the top-level definition.
|
|
(macroexpand (macroexpand-all-forms form 1)
|
|
macroexpand-all-environment)
|
|
;; Normal form; get its expansion, and then expand arguments.
|
|
(setq form (macroexpand form macroexpand-all-environment))
|
|
(if (consp form)
|
|
(let ((fun (car form)))
|
|
(cond
|
|
((eq fun 'cond)
|
|
(maybe-cons fun (macroexpand-all-clauses (cdr form)) form))
|
|
((eq fun 'condition-case)
|
|
(maybe-cons
|
|
fun
|
|
(maybe-cons (cadr form)
|
|
(maybe-cons (macroexpand-all-1 (nth 2 form))
|
|
(macroexpand-all-clauses (nthcdr 3 form) 1)
|
|
(cddr form))
|
|
(cdr form))
|
|
form))
|
|
((eq fun 'defmacro)
|
|
(push (cons (cadr form) (cons 'lambda (cddr form)))
|
|
macroexpand-all-environment)
|
|
(macroexpand-all-forms form 3))
|
|
((eq fun 'defun)
|
|
(macroexpand-all-forms form 3))
|
|
((memq fun '(defvar defconst))
|
|
(macroexpand-all-forms form 2))
|
|
((eq fun 'function)
|
|
(if (and (consp (cadr form)) (eq (car (cadr form)) 'lambda))
|
|
(maybe-cons fun
|
|
(maybe-cons (macroexpand-all-forms (cadr form) 2)
|
|
nil
|
|
(cadr form))
|
|
form)
|
|
form))
|
|
((memq fun '(let let*))
|
|
(maybe-cons fun
|
|
(maybe-cons (macroexpand-all-clauses (cadr form) 1)
|
|
(macroexpand-all-forms (cddr form))
|
|
(cdr form))
|
|
form))
|
|
((eq fun 'quote)
|
|
form)
|
|
((and (consp fun) (eq (car fun) 'lambda))
|
|
;; embedded lambda
|
|
(maybe-cons (macroexpand-all-forms fun 2)
|
|
(macroexpand-all-forms (cdr form))
|
|
form))
|
|
;; The following few cases are for normal function calls that
|
|
;; are known to funcall one of their arguments. The byte
|
|
;; compiler has traditionally handled these functions specially
|
|
;; by treating a lambda expression quoted by `quote' as if it
|
|
;; were quoted by `function'. We make the same transformation
|
|
;; here, so that any code that cares about the difference will
|
|
;; see the same transformation.
|
|
;; First arg is a function:
|
|
((and (memq fun '(apply mapcar mapatoms mapconcat mapc))
|
|
(consp (cadr form))
|
|
(eq (car (cadr form)) 'quote))
|
|
;; We don't use `maybe-cons' since there's clearly a change.
|
|
(cons fun
|
|
(cons (macroexpand-all-1 (cons 'function (cdr (cadr form))))
|
|
(macroexpand-all-forms (cddr form)))))
|
|
;; Second arg is a function:
|
|
((and (eq fun 'sort)
|
|
(consp (nth 2 form))
|
|
(eq (car (nth 2 form)) 'quote))
|
|
;; We don't use `maybe-cons' since there's clearly a change.
|
|
(cons fun
|
|
(cons (macroexpand-all-1 (cadr form))
|
|
(cons (macroexpand-all-1
|
|
(cons 'function (cdr (nth 2 form))))
|
|
(macroexpand-all-forms (nthcdr 3 form))))))
|
|
(t
|
|
;; For everything else, we just expand each argument (for
|
|
;; setq/setq-default this works alright because the variable names
|
|
;; are symbols).
|
|
(macroexpand-all-forms form 1))))
|
|
form)))
|
|
|
|
;;;###autoload
|
|
(defun macroexpand-all (form &optional environment)
|
|
"Return result of expanding macros at all levels in FORM.
|
|
If no macros are expanded, FORM is returned unchanged.
|
|
The second optional arg ENVIRONMENT specifies an environment of macro
|
|
definitions to shadow the loaded ones for use in file byte-compilation."
|
|
(let ((macroexpand-all-environment environment))
|
|
(macroexpand-all-1 form)))
|
|
|
|
(provide 'macroexp)
|
|
|
|
;;; arch-tag: af9b8c24-c196-43bc-91e1-a3570790fa5a
|
|
;;; macroexp.el ends here
|