bug#25942: 26.0.50; dired-mark-extension prepend '.' to suffix if not present

[Tino Calancha <tino.calancha@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Tino Calancha <tino.calancha@gmail.com>
>> Date: Mon, 27 Mar 2017 10:30:26 +0900 (JST)
>> Cc: 25942@debbugs.gnu.org, Tino Calancha <tino.calancha@gmail.com>
>> 
>> The problem is that this command has a concept of 'extension' different 
>> than the two other functions mentioned above.
>
> Then how about providing a new command, named dired-mark-suffix or
> somesuch, which would work like dired-mark-extension does now?  Or
> maybe have an optional argument, activated by prefix arg to
> dired-mark-extension, to do that?  That would leave users a way to get
> back the old behavior, if they want.
I like your first suggestion.  The second is less convenient because we
already use prefices 'C-u' and 'C-u C-u'.

The following patch adds a new command 'dired-mark-suffix', and
modifies 'dired-mark-extension'.
I) dired-mark-suffix: it behaves as 'dired-mark-extension' used to do,
   i.e., don't prepends any '.' to the user input.
II) dired-mark-extension: It prepends '.' to EXTENSION when not present.
    This way became consistent with 'file-name-extension', that is, if
    (file-name-extension FILE) returns nil, then 'dired-mark-extension'
    will not mark FILE.

--8<-----------------------------cuthere---------------start------------->8---
From e995e2ab6ffbd1ef94b9548d492394f9283fe490 Mon Sep 17 00:00:00 2001
From: Tino Calancha <tino.calancha@gmail.com>
Date: Mon, 27 Mar 2017 14:31:35 +0900
Subject: [PATCH] dired-mark-suffix: New command

Now dired-mark-extension prepends '.' to extension when not present.
Add the new command dired-mark-suffix to preserve the previous
behaviour (Bug#25942).
* lisp/dired-x.el (dired-mark-suffix): New command;
mark files ending in a given suffix.
(dired--mark-suffix-interactive-spec): New defun.
(dired-mark-extension, dired-mark-suffix): Use it.
* doc/misc/dired-x.texi (Advanced Mark Commands): Update manual.
; * etc/NEWS (Changes in Specialized Modes and Packages in Emacs 26.1):
; Mention these changes.
---
 doc/misc/dired-x.texi | 16 +++++++++--
 etc/NEWS              |  5 ++++
 lisp/dired-x.el       | 80 ++++++++++++++++++++++++++++++++++-----------------
 3 files changed, 73 insertions(+), 28 deletions(-)

diff --git a/doc/misc/dired-x.texi b/doc/misc/dired-x.texi
index 1e6f4b03bb..369b2da42a 100644
--- a/doc/misc/dired-x.texi
+++ b/doc/misc/dired-x.texi
@@ -721,8 +721,7 @@ Advanced Mark Commands
 @item dired-mark-extension
 @findex dired-mark-extension
 Mark all files with a certain extension for use in later commands.  A @samp{.}
-is not automatically prepended to the string entered, you must type it
-explicitly.
+is automatically prepended to the string entered when not present.
 If invoked with prefix argument @kbd{C-u}, this command unmark files instead.
 If called with the @kbd{C-u C-u} prefix, asks for a character to use
 as the marker, and marks files with it.
@@ -730,6 +729,19 @@ Advanced Mark Commands
 When called from Lisp, @var{extension} may also be a list of extensions
 and an optional argument @var{marker-char} specifies the marker used.
 
+@item dired-mark-suffix
+@findex dired-mark-suffix
+Mark all files with a certain suffix for use in later commands.  A @samp{.}
+is not automatically prepended to the string entered, you must type it
+explicitly.  This is different than @var{dired-mark-extension} which prepends
+a @samp{.} if not present.
+If invoked with prefix argument @kbd{C-u}, this command unmark files instead.
+If called with the @kbd{C-u C-u} prefix, asks for a character to use
+as the marker, and marks files with it.
+
+When called from Lisp, @var{suffix} may also be a list of suffices
+and an optional argument @var{marker-char} specifies the marker used.
+
 @item dired-flag-extension
 @findex dired-flag-extension
 Flag all files with a certain extension for deletion.  A @samp{.} is
diff --git a/etc/NEWS b/etc/NEWS
index cd98f53399..3839439a32 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -474,6 +474,11 @@ where to place point after C-c M-r and C-c M-s.
 ** Dired
 
 +++
+*** Command 'dired-mark-extension' now automatically prepends a '.' to the
+extension when not present.  The new command 'dired-mark-suffix' behaves
+similarly but it doesn't prepend a '.'.
+
++++
 *** A new option 'dired-always-read-filesystem' default to nil.
 If non-nil, buffers visiting files are reverted before search them;
 for instance, in 'dired-mark-files-containing-regexp' a non-nil value
diff --git a/lisp/dired-x.el b/lisp/dired-x.el
index 6c8fb0e7da..a043784a75 100644
--- a/lisp/dired-x.el
+++ b/lisp/dired-x.el
@@ -332,46 +332,74 @@ dired-extra-startup
 \f
 ;;; EXTENSION MARKING FUNCTIONS.
 
+(defun dired--mark-suffix-interactive-spec ()
+  (let* ((default
+           (let ((file (dired-get-filename nil t)))
+             (when file
+               (file-name-extension file))))
+         (suffix
+          (read-string (format "%s extension%s: "
+                               (if (equal current-prefix-arg '(4))
+                                   "UNmarking"
+                                 "Marking")
+                               (if default
+                                   (format " (default %s)" default)
+                                 "")) nil nil default))
+         (marker
+          (pcase current-prefix-arg
+            ('(4) ?\s)
+            ('(16)
+             (let* ((dflt (char-to-string dired-marker-char))
+                    (input (read-string
+                            (format
+                             "Marker character to use (default %s): " dflt)
+                            nil nil dflt)))
+               (aref input 0)))
+            (_ dired-marker-char))))
+    (list suffix marker)))
+
 ;; Mark files with some extension.
 (defun dired-mark-extension (extension &optional marker-char)
   "Mark all files with a certain EXTENSION for use in later commands.
-A `.' is *not* automatically prepended to the string entered.
+A `.' before EXTENSION is automatically prepended when not present.
 EXTENSION may also be a list of extensions instead of a single one.
 Optional MARKER-CHAR is marker to use.
 Interactively, ask for EXTENSION.
 Prefixed with one C-u, unmark files instead.
 Prefixed with two C-u's, prompt for MARKER-CHAR and mark files with it."
   (interactive
-   (let* ((default
-            (let ((file (dired-get-filename nil t)))
-              (when file
-                (file-name-extension file))))
-          (suffix
-           (read-string (format "%s extension%s: "
-                                (if (equal current-prefix-arg '(4))
-                                    "UNmarking"
-                                  "Marking")
-                                (if default
-                                    (format " (default %s)" default)
-                                  "")) nil nil default))
-          (marker
-           (pcase current-prefix-arg
-             ('(4) ?\s)
-             ('(16)
-              (let* ((dflt (char-to-string dired-marker-char))
-                     (input (read-string
-                             (format
-                              "Marker character to use (default %s): " dflt)
-                             nil nil dflt)))
-                (aref input 0)))
-             (_ dired-marker-char))))
-     (list suffix marker)))
+   (dired--mark-suffix-interactive-spec))
   (or (listp extension)
       (setq extension (list extension)))
   (dired-mark-files-regexp
    (concat ".";; don't match names with nothing but an extension
            "\\("
-           (mapconcat 'regexp-quote extension "\\|")
+           (mapconcat (lambda (x)
+                        (regexp-quote
+                         (if (string-prefix-p "." x) x (concat "." x))))
+                      extension "\\|")
+           "\\)$")
+   marker-char))
+
+;; Mark files ending with some suffix.
+(defun dired-mark-suffix (suffix &optional marker-char)
+  "Mark all files with a certain SUFFIX for use in later commands.
+A `.' is *not* automatically prepended to the string entered;  see
+also `dired-mark-extension', which is similar but automatically
+prepends `.' when not present.
+SUFFIX may also be a list of suffices instead of a single one.
+Optional MARKER-CHAR is marker to use.
+Interactively, ask for SUFFIX.
+Prefixed with one C-u, unmark files instead.
+Prefixed with two C-u's, prompt for MARKER-CHAR and mark files with it."
+  (interactive
+   (dired--mark-suffix-interactive-spec))
+  (or (listp suffix)
+      (setq suffix (list suffix)))
+  (dired-mark-files-regexp
+   (concat ".";; don't match names with nothing but an extension
+           "\\("
+           (mapconcat 'regexp-quote suffix "\\|")
            "\\)$")
    marker-char))
 
-- 
2.11.0

--8<-----------------------------cut here---------------end--------------->8---
In GNU Emacs 26.0.50 (build 12, x86_64-pc-linux-gnu, GTK+ Version 3.22.9)
 of 2017-03-27
Repository revision: 05bfebfc91bc053435287f560aeb956926d31583