* subr.el (string-or-null-p): New function.

* textmodes/paragraphs.el (sentence-end): Use string-or-null-p.

* textmodes/ispell.el (ispell-local-dictionary): Use
string-or-null-p.

* files.el: Update comment about safe-local-variable declarations.

5 files changed, 37 insertions, 11 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index a0d8e64a1fc..f914e5dbc48 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,14 @@
+2006-04-06  Reiner Steib  <Reiner.Steib@gmx.de>
+
+        * subr.el (string-or-null-p): New function.
+
+        * textmodes/paragraphs.el (sentence-end): Use string-or-null-p.
+
+        * textmodes/ispell.el (ispell-local-dictionary): Use
+        string-or-null-p.
+
+        * files.el: Update comment about safe-local-variable declarations.
+
 2006-04-06  J.D. Smith  <jdsmith@as.arizona.edu>
 
         * progmodes/idlwave.el: Updated to IDLWAVE version 6.0.  See
diff --git a/lisp/files.el b/lisp/files.el
index 7ab7d593e4c..2ca497e09b1 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -2322,13 +2322,22 @@ asking you for confirmation."
 
 ;; Safe local variables:
 ;;
-;; For variables defined by minor modes, put the safety declarations
-;; here, not in the file defining the minor mode (when Emacs visits a
-;; file specifying that local variable, the minor mode file may not be
-;; loaded yet).  For variables defined by major modes, the safety
-;; declarations can go into the major mode's file, since that will be
-;; loaded before file variables are processed.
+;; For variables defined by major modes, the safety declarations can go into
+;; the major mode's file, since that will be loaded before file variables are
+;; processed.
+;;
+;; For variables defined by minor modes, put the safety declarations in the
+;; file defining the minor mode after the defcustom/defvar using an autoload
+;; cookie, e.g.:
+;;
+;;   ;;;###autoload(put 'variable 'safe-local-variable 'stringp)
+;;
+;; Otherwise, when Emacs visits a file specifying that local variable, the
+;; minor mode file may not be loaded yet.
+;;
+;; For variables defined in the C source code the declaration should go here:
 
+;; FIXME: Some variables should be moved according to the rules above.
 (let ((string-or-null (lambda (a) (or (stringp a) (null a)))))
   (eval
    `(mapc (lambda (pair)
@@ -2340,15 +2349,15 @@ asking you for confirmation."
             (c-file-style       .  stringp)
             (c-indent-level     .  integerp)
             (comment-column     .  integerp)
-            (compile-command    . ,string-or-null)
+            (compile-command    .  string-or-null-p)
             (fill-column        .  integerp)
-            (fill-prefix        . ,string-or-null)
+            (fill-prefix        .  string-or-null-p)
             (indent-tabs-mode   .  t)
             (kept-new-versions  .  integerp)
             (left-margin        .  t)
             (no-byte-compile    .  t)
             (no-update-autoloads . t)
-            (outline-regexp     . ,string-or-null)
+            (outline-regexp     .  string-or-null-p)
             (tab-width          .  integerp) ;; C source code
             (truncate-lines     .  t) ;; C source code
             (version-control    .  t)))))
diff --git a/lisp/subr.el b/lisp/subr.el
index f515b6b3753..9aba6195816 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -1916,6 +1916,12 @@ a system-dependent default device name is used."
                                  "\\" (substring argument end (1+ end)))
                   start (1+ end)))
           (concat result (substring argument start)))))))
+
+(defun string-or-null-p (object)
+  "Return t if OBJECT is a string or nil.
+Otherwise, return nil."
+  (or (stringp object) (null object)))
+
 
 ;;;; Support for yanking and text properties.
 
diff --git a/lisp/textmodes/ispell.el b/lisp/textmodes/ispell.el
index 8a08f9dd078..da77508dce3 100644
--- a/lisp/textmodes/ispell.el
+++ b/lisp/textmodes/ispell.el
@@ -462,7 +462,7 @@ is automatically set when defined in the file with either
   :type '(choice string
                  (const :tag "default" nil))
   :group 'ispell)
-;;;###autoload(put 'ispell-local-dictionary 'safe-local-variable (lambda (a) (or (stringp a) (null a))))
+;;;###autoload(put 'ispell-local-dictionary 'safe-local-variable 'string-or-null-p)
 
 (make-variable-buffer-local 'ispell-local-dictionary)
 
diff --git a/lisp/textmodes/paragraphs.el b/lisp/textmodes/paragraphs.el
index c62f337e456..6693be4e0c9 100644
--- a/lisp/textmodes/paragraphs.el
+++ b/lisp/textmodes/paragraphs.el
@@ -163,7 +163,7 @@ function `sentence-end'.  You should always use this function
 to obtain the value of this variable."
   :group 'paragraphs
   :type '(choice regexp (const :tag "Use default value" nil)))
-;;;###autoload(put 'sentence-end 'safe-local-variable (lambda (a) (or (stringp a) (null a))))
+;;;###autoload(put 'sentence-end 'safe-local-variable 'string-or-null-p)
 
 (defcustom sentence-end-base "[.?!][]\"'$B!I$,1r}(B)}]*"
   "*Regexp matching the basic end of a sentence, not including following space."