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a9de04fa | 1 | ;;; macroexp.el --- Additional macro-expansion support -*- lexical-binding: t -*- |
4d449b11 | 2 | ;; |
acaf905b | 3 | ;; Copyright (C) 2004-2012 Free Software Foundation, Inc. |
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4 | ;; |
5 | ;; Author: Miles Bader <miles@gnu.org> | |
6 | ;; Keywords: lisp, compiler, macros | |
7 | ||
8 | ;; This file is part of GNU Emacs. | |
9 | ||
d6cba7ae | 10 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
4d449b11 | 11 | ;; it under the terms of the GNU General Public License as published by |
d6cba7ae GM |
12 | ;; the Free Software Foundation, either version 3 of the License, or |
13 | ;; (at your option) any later version. | |
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14 | |
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
d6cba7ae | 21 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
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22 | |
23 | ;;; Commentary: | |
24 | ;; | |
25 | ;; This file contains macro-expansions functions that are not defined in | |
26 | ;; the Lisp core, namely `macroexpand-all', which expands all macros in | |
27 | ;; a form, not just a top-level one. | |
28 | ;; | |
29 | ||
30 | ;;; Code: | |
31 | ||
43e67019 SM |
32 | (eval-when-compile (require 'cl)) |
33 | ||
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34 | ;; Bound by the top-level `macroexpand-all', and modified to include any |
35 | ;; macros defined by `defmacro'. | |
36 | (defvar macroexpand-all-environment nil) | |
37 | ||
38 | (defun maybe-cons (car cdr original-cons) | |
39 | "Return (CAR . CDR), using ORIGINAL-CONS if possible." | |
40 | (if (and (eq car (car original-cons)) (eq cdr (cdr original-cons))) | |
41 | original-cons | |
42 | (cons car cdr))) | |
43 | ||
44 | ;; We use this special macro to iteratively process forms and share list | |
45 | ;; structure of the result with the input. Doing so recursively using | |
46 | ;; `maybe-cons' results in excessively deep recursion for very long | |
47 | ;; input forms. | |
5de35ba4 | 48 | (defmacro macroexp-accumulate (var+list &rest body) |
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49 | "Return a list of the results of evaluating BODY for each element of LIST. |
50 | Evaluate BODY with VAR bound to each `car' from LIST, in turn. | |
51 | Return a list of the values of the final form in BODY. | |
52 | The list structure of the result will share as much with LIST as | |
53 | possible (for instance, when BODY just returns VAR unchanged, the | |
5de35ba4 RS |
54 | result will be eq to LIST). |
55 | ||
56 | \(fn (VAR LIST) BODY...)" | |
6fe79b7c | 57 | (declare (indent 1)) |
5de35ba4 RS |
58 | (let ((var (car var+list)) |
59 | (list (cadr var+list)) | |
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60 | (shared (make-symbol "shared")) |
61 | (unshared (make-symbol "unshared")) | |
62 | (tail (make-symbol "tail")) | |
63 | (new-el (make-symbol "new-el"))) | |
64 | `(let* ((,shared ,list) | |
65 | (,unshared nil) | |
66 | (,tail ,shared) | |
67 | ,var ,new-el) | |
68 | (while ,tail | |
69 | (setq ,var (car ,tail) | |
70 | ,new-el (progn ,@body)) | |
71 | (unless (eq ,var ,new-el) | |
72 | (while (not (eq ,shared ,tail)) | |
73 | (push (pop ,shared) ,unshared)) | |
74 | (setq ,shared (cdr ,shared)) | |
75 | (push ,new-el ,unshared)) | |
76 | (setq ,tail (cdr ,tail))) | |
77 | (nconc (nreverse ,unshared) ,shared)))) | |
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78 | |
79 | (defun macroexpand-all-forms (forms &optional skip) | |
80 | "Return FORMS with macros expanded. FORMS is a list of forms. | |
81 | If SKIP is non-nil, then don't expand that many elements at the start of | |
82 | FORMS." | |
83 | (macroexp-accumulate (form forms) | |
84 | (if (or (null skip) (zerop skip)) | |
85 | (macroexpand-all-1 form) | |
86 | (setq skip (1- skip)) | |
87 | form))) | |
88 | ||
89 | (defun macroexpand-all-clauses (clauses &optional skip) | |
90 | "Return CLAUSES with macros expanded. | |
91 | CLAUSES is a list of lists of forms; any clause that's not a list is ignored. | |
92 | If SKIP is non-nil, then don't expand that many elements at the start of | |
93 | each clause." | |
3731a850 | 94 | (macroexp-accumulate (clause clauses) |
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95 | (if (listp clause) |
96 | (macroexpand-all-forms clause skip) | |
97 | clause))) | |
98 | ||
99 | (defun macroexpand-all-1 (form) | |
100 | "Expand all macros in FORM. | |
101 | This is an internal version of `macroexpand-all'. | |
102 | Assumes the caller has bound `macroexpand-all-environment'." | |
103 | (if (and (listp form) (eq (car form) 'backquote-list*)) | |
104 | ;; Special-case `backquote-list*', as it is normally a macro that | |
105 | ;; generates exceedingly deep expansions from relatively shallow input | |
106 | ;; forms. We just process it `in reverse' -- first we expand all the | |
107 | ;; arguments, _then_ we expand the top-level definition. | |
108 | (macroexpand (macroexpand-all-forms form 1) | |
109 | macroexpand-all-environment) | |
110 | ;; Normal form; get its expansion, and then expand arguments. | |
a9de04fa SM |
111 | (let ((new-form (macroexpand form macroexpand-all-environment))) |
112 | (when (and (not (eq form new-form)) ;It was a macro call. | |
113 | (car-safe form) | |
114 | (symbolp (car form)) | |
115 | (get (car form) 'byte-obsolete-info) | |
116 | (fboundp 'byte-compile-warn-obsolete)) | |
117 | (byte-compile-warn-obsolete (car form))) | |
118 | (setq form new-form)) | |
6fe79b7c SM |
119 | (pcase form |
120 | (`(cond . ,clauses) | |
121 | (maybe-cons 'cond (macroexpand-all-clauses clauses) form)) | |
122 | (`(condition-case . ,(or `(,err ,body . ,handlers) dontcare)) | |
123 | (maybe-cons | |
124 | 'condition-case | |
125 | (maybe-cons err | |
126 | (maybe-cons (macroexpand-all-1 body) | |
127 | (macroexpand-all-clauses handlers 1) | |
128 | (cddr form)) | |
129 | (cdr form)) | |
130 | form)) | |
131 | (`(defmacro ,name . ,args-and-body) | |
132 | (push (cons name (cons 'lambda args-and-body)) | |
133 | macroexpand-all-environment) | |
ba83908c SM |
134 | (let ((n 3)) |
135 | ;; Don't macroexpand `declare' since it should really be "expanded" | |
136 | ;; away when `defmacro' is expanded, but currently defmacro is not | |
137 | ;; itself a macro. So both `defmacro' and `declare' need to be | |
138 | ;; handled directly in bytecomp.el. | |
139 | ;; FIXME: Maybe a simpler solution is to (defalias 'declare 'quote). | |
140 | (while (or (stringp (nth n form)) | |
141 | (eq (car-safe (nth n form)) 'declare)) | |
142 | (setq n (1+ n))) | |
143 | (macroexpand-all-forms form n))) | |
6fe79b7c SM |
144 | (`(defun . ,_) (macroexpand-all-forms form 3)) |
145 | (`(,(or `defvar `defconst) . ,_) (macroexpand-all-forms form 2)) | |
146 | (`(function ,(and f `(lambda . ,_))) | |
147 | (maybe-cons 'function | |
148 | (maybe-cons (macroexpand-all-forms f 2) | |
149 | nil | |
150 | (cdr form)) | |
151 | form)) | |
152 | (`(,(or `function `quote) . ,_) form) | |
153 | (`(,(and fun (or `let `let*)) . ,(or `(,bindings . ,body) dontcare)) | |
154 | (maybe-cons fun | |
155 | (maybe-cons (macroexpand-all-clauses bindings 1) | |
156 | (macroexpand-all-forms body) | |
157 | (cdr form)) | |
158 | form)) | |
159 | (`(,(and fun `(lambda . ,_)) . ,args) | |
160 | ;; Embedded lambda in function position. | |
161 | (maybe-cons (macroexpand-all-forms fun 2) | |
162 | (macroexpand-all-forms args) | |
163 | form)) | |
164 | ;; The following few cases are for normal function calls that | |
165 | ;; are known to funcall one of their arguments. The byte | |
166 | ;; compiler has traditionally handled these functions specially | |
167 | ;; by treating a lambda expression quoted by `quote' as if it | |
168 | ;; were quoted by `function'. We make the same transformation | |
169 | ;; here, so that any code that cares about the difference will | |
170 | ;; see the same transformation. | |
171 | ;; First arg is a function: | |
9c848d8a | 172 | (`(,(and fun (or `funcall `apply `mapcar `mapatoms `mapconcat `mapc)) |
876c194c | 173 | ',(and f `(lambda . ,_)) . ,args) |
9c848d8a SM |
174 | (byte-compile-log-warning |
175 | (format "%s quoted with ' rather than with #'" | |
176 | (list 'lambda (nth 1 f) '...)) | |
177 | t) | |
6fe79b7c SM |
178 | ;; We don't use `maybe-cons' since there's clearly a change. |
179 | (cons fun | |
180 | (cons (macroexpand-all-1 (list 'function f)) | |
181 | (macroexpand-all-forms args)))) | |
182 | ;; Second arg is a function: | |
876c194c | 183 | (`(,(and fun (or `sort)) ,arg1 ',(and f `(lambda . ,_)) . ,args) |
9c848d8a SM |
184 | (byte-compile-log-warning |
185 | (format "%s quoted with ' rather than with #'" | |
186 | (list 'lambda (nth 1 f) '...)) | |
187 | t) | |
6fe79b7c SM |
188 | ;; We don't use `maybe-cons' since there's clearly a change. |
189 | (cons fun | |
190 | (cons (macroexpand-all-1 arg1) | |
191 | (cons (macroexpand-all-1 | |
192 | (list 'function f)) | |
193 | (macroexpand-all-forms args))))) | |
2ec42da9 SM |
194 | ;; Macro expand compiler macros. This cannot be delayed to |
195 | ;; byte-optimize-form because the output of the compiler-macro can | |
196 | ;; use macros. | |
43e67019 | 197 | ;; FIXME: Don't depend on CL. |
e2abe5a1 SM |
198 | (`(,(pred (lambda (fun) |
199 | (and (symbolp fun) | |
200 | (eq (get fun 'byte-compile) | |
201 | 'cl-byte-compile-compiler-macro) | |
202 | (functionp 'compiler-macroexpand)))) | |
43e67019 | 203 | . ,_) |
2ec42da9 | 204 | (let ((newform (with-no-warnings (compiler-macroexpand form)))) |
43e67019 SM |
205 | (if (eq form newform) |
206 | (macroexpand-all-forms form 1) | |
207 | (macroexpand-all-1 newform)))) | |
6fe79b7c SM |
208 | (`(,_ . ,_) |
209 | ;; For every other list, we just expand each argument (for | |
210 | ;; setq/setq-default this works alright because the variable names | |
211 | ;; are symbols). | |
212 | (macroexpand-all-forms form 1)) | |
213 | (t form)))) | |
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214 | |
215 | ;;;###autoload | |
216 | (defun macroexpand-all (form &optional environment) | |
217 | "Return result of expanding macros at all levels in FORM. | |
218 | If no macros are expanded, FORM is returned unchanged. | |
219 | The second optional arg ENVIRONMENT specifies an environment of macro | |
220 | definitions to shadow the loaded ones for use in file byte-compilation." | |
221 | (let ((macroexpand-all-environment environment)) | |
222 | (macroexpand-all-1 form))) | |
223 | ||
224 | (provide 'macroexp) | |
225 | ||
4d449b11 | 226 | ;;; macroexp.el ends here |