summaryrefslogtreecommitdiff
path: root/lisp/mh-e/mh-acros.el
blob: 5cb1c26248b53a0310371603dcbd916479341d00 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
;;; mh-acros.el --- Macros used in MH-E

;; Copyright (C) 2004 Free Software Foundation, Inc.

;; Author: Satyaki Das <satyaki@theforce.stanford.edu>
;; Maintainer: Bill Wohler <wohler@newt.com>
;; Keywords: mail
;; See: mh-e.el

;; 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., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; This file contains macros that would normally be in mh-utils.el except that
;; their presence there would cause a dependency loop with mh-customize.el.
;; This file must always be included like this:
;;
;;   (eval-when-compile (require 'mh-acros))
;;
;; It is so named with a silent `m' so that it is compiled first. Otherwise,
;; "make recompile" in Emacs 21.4 fails.

;;; Change Log:

;;; Code:

(require 'cl)
(require 'advice)

;; The Emacs coding conventions require that the cl package not be required at
;; runtime. However, the cl package in versions of Emacs prior to 21.4 left cl
;; routines in their macro expansions. Use mh-require-cl to provide the cl
;; routines in the best way possible.
(defmacro mh-require-cl ()
  "Macro to load `cl' if needed.
Some versions of `cl' produce code for the expansion of
\(setf (gethash ...) ...) that uses functions in `cl' at run time.  This macro
recognizes that and loads `cl' where appropriate."
  (if (eq (car (macroexpand '(setf (gethash foo bar) baz))) 'cl-puthash)
      `(require 'cl)
    `(eval-when-compile (require 'cl))))

;;; Macros to generate correct code for different emacs variants

(defmacro mh-do-in-gnu-emacs (&rest body)
  "Execute BODY if in GNU Emacs."
  (unless (featurep 'xemacs) `(progn ,@body)))
(put 'mh-do-in-gnu-emacs 'lisp-indent-hook 'defun)

(defmacro mh-do-in-xemacs (&rest body)
  "Execute BODY if in GNU Emacs."
  (when (featurep 'xemacs) `(progn ,@body)))
(put 'mh-do-in-xemacs 'lisp-indent-hook 'defun)

(defmacro mh-funcall-if-exists (function &rest args)
  "Call FUNCTION with ARGS as parameters if it exists."
  (when (fboundp function)
    `(when (fboundp ',function)
       (funcall ',function ,@args))))

(defmacro mh-make-local-hook (hook)
  "Make HOOK local if needed.
XEmacs and versions of GNU Emacs before 21.1 require `make-local-hook' to be
called."
  (when (and (fboundp 'make-local-hook)
             (not (get 'make-local-hook 'byte-obsolete-info)))
    `(make-local-hook ,hook)))

(defmacro mh-mark-active-p (check-transient-mark-mode-flag)
  "A macro that expands into appropriate code in XEmacs and nil in GNU Emacs.
In GNU Emacs if CHECK-TRANSIENT-MARK-MODE-FLAG is non-nil then check if
variable `transient-mark-mode' is active."
  (cond ((featurep 'xemacs)             ;XEmacs
         `(and (boundp 'zmacs-regions) zmacs-regions (region-active-p)))
        ((not check-transient-mark-mode-flag) ;GNU Emacs
         `(and (boundp 'mark-active) mark-active))
        (t                              ;GNU Emacs
         `(and (boundp 'transient-mark-mode) transient-mark-mode
               (boundp 'mark-active) mark-active))))

(defmacro mh-defstruct (name-spec &rest fields)
  "Replacement for `defstruct' from the `cl' package.
The `defstruct' in the `cl' library produces compiler warnings, and generates
code that uses functions present in `cl' at run-time.  This is a partial
replacement, that avoids these issues.

NAME-SPEC declares the name of the structure, while FIELDS describes the
various structure fields. Lookup `defstruct' for more details."
  (let* ((struct-name (if (atom name-spec) name-spec (car name-spec)))
         (conc-name (or (and (consp name-spec)
                             (cadr (assoc :conc-name (cdr name-spec))))
                        (format "%s-" struct-name)))
         (predicate (intern (format "%s-p" struct-name)))
         (constructor (or (and (consp name-spec)
                               (cadr (assoc :constructor (cdr name-spec))))
                          (intern (format "make-%s" struct-name))))
         (field-names (mapcar #'(lambda (x) (if (atom x) x (car x))) fields))
         (field-init-forms (mapcar #'(lambda (x) (and (consp x) (cadr x)))
                                   fields))
         (struct (gensym "S"))
         (x (gensym "X"))
         (y (gensym "Y")))
    `(progn
       (defun* ,constructor (&key ,@(mapcar* #'(lambda (x y) (list x y))
                                             field-names field-init-forms))
         (list (quote ,struct-name) ,@field-names))
       (defun ,predicate (arg)
         (and (consp arg) (eq (car arg) (quote ,struct-name))))
       ,@(loop for x from 1
               for y in field-names
               collect `(defmacro ,(intern (format "%s%s" conc-name y)) (z)
                          (list 'nth ,x z)))
       (quote ,struct-name))))

(defadvice require (around mh-prefer-el activate)
  "Modify `require' to load uncompiled MH-E files."
  (or (featurep (ad-get-arg 0))
      (and (string-match "^mh-" (symbol-name (ad-get-arg 0)))
           (load (format "%s.el" (ad-get-arg 0)) t t))
      ad-do-it))

(provide 'mh-acros)

;;; Local Variables:
;;; no-byte-compile: t
;;; indent-tabs-mode: nil
;;; sentence-end-double-space: nil
;;; End:

;; arch-tag: b383b49a-494f-4ed0-a30a-cb6d5d2da4ff
;;; mh-acros.el ends here