From: "Colin Woodbury" <colin@fosskers.ca>
To: "Stefan Monnier" <monnier@iro.umontreal.ca>
Cc: "Mattias Engdegård" <mattiase@acm.org>,
Philipp <p.stephani2@gmail.com>,
emacs-devel@gnu.org
Subject: Re: [PATCH] lisp/files.el: Add `file-name-set-extension`
Date: Wed, 09 Jun 2021 19:45:07 -0700 [thread overview]
Message-ID: <8d754566-279f-46e4-9489-d29356a1189b@www.fastmail.com> (raw)
In-Reply-To: <c70420c6-0eba-4d63-a3fe-f8032c5ea229@www.fastmail.com>
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And while I'm at, I've tweaked one line to use `aref` to access the final character of the filename directly, which avoids a (albeit minor) string allocation.
On Wed, 9 Jun 2021, at 17:42, Colin Woodbury wrote:
> So be it! I've updated the patch.
>
> Colin
>
> On Wed, 9 Jun 2021, at 16:05, Stefan Monnier wrote:
>> > As for the naming of `set-extension`, the best I can think of as an
>> > alternative would be `with-extension` as a dual to `sans-extension`,
>>
>> `file-name-with-extension` sounds good to me (better than `...set...`).
>>
>>
>> Stefan
>>
>>
>
>
> *Attachments:*
> * file-name-with-extension.patch
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diff --git a/lisp/files.el b/lisp/files.el
index 2450daf5bf..c6938eb1c8 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -4892,6 +4892,20 @@ extension, the value is \"\"."
(if period
"")))))
+(defun file-name-with-extension (filename extension)
+ "Set the EXTENSION of a FILENAME.
+Consolidates leading/trailing dots so that either `foo' or `.foo'
+can be passed as an EXTENSION.
+
+See also `file-name-sans-extension'."
+ (let* ((patt "[ .]+")
+ (file (string-trim-right filename patt))
+ (extn (string-trim-left extension patt)))
+ (cond ((string-empty-p file) (error "Malformed filename: %s" filename))
+ ((string-empty-p extn) (error "Malformed extension: %s" extension))
+ ((equal ?/ (aref file (1- (length file)))) (error "Filename is a directory: %s" filename))
+ (t (concat (file-name-sans-extension file) "." extn)))))
+
(defun file-name-base (&optional filename)
"Return the base name of the FILENAME: no directory, no extension."
(declare (advertised-calling-convention (filename) "27.1"))
diff --git a/test/lisp/files-tests.el b/test/lisp/files-tests.el
index dc96dff639..80f47a78dc 100644
--- a/test/lisp/files-tests.el
+++ b/test/lisp/files-tests.el
@@ -1478,5 +1478,25 @@ The door of all subtleties!
(buffer-substring (point-min) (point-max))
nil nil)))))
+(ert-deftest files-tests-file-name-with-extension-good ()
+ "Test that `file-name-with-extension' succeeds with reasonable input."
+ (should (string= (file-name-with-extension "Jack" "css") "Jack.css"))
+ (should (string= (file-name-with-extension "Jack" ".css") "Jack.css"))
+ (should (string= (file-name-with-extension "Jack.scss" "css") "Jack.css"))
+ (should (string= (file-name-with-extension "Jack..." "...css") "Jack.css"))
+ (should (string= (file-name-with-extension "/path/to/Jack.md" "org") "/path/to/Jack.org")))
+
+(ert-deftest files-tests-file-name-with-extension-bad ()
+ "Test that `file-name-with-extension' fails on malformed input."
+ (should-error (file-name-with-extension nil nil))
+ (should-error (file-name-with-extension "Jack" nil))
+ (should-error (file-name-with-extension nil "css"))
+ (should-error (file-name-with-extension "" ""))
+ (should-error (file-name-with-extension "" "css"))
+ (should-error (file-name-with-extension "Jack" ""))
+ (should-error (file-name-with-extension "Jack" "..."))
+ (should-error (file-name-with-extension "..." "css"))
+ (should-error (file-name-with-extension "/is/a/directory/" "css")))
+
(provide 'files-tests)
;;; files-tests.el ends here
next prev parent reply other threads:[~2021-06-10 2:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-25 15:50 [PATCH] lisp/files.el: Add `file-name-set-extension` Colin Woodbury
2021-05-25 17:48 ` Andreas Schwab
2021-05-25 19:42 ` Colin Woodbury
2021-05-25 18:00 ` Basil L. Contovounesios
2021-05-25 19:45 ` Colin Woodbury
2021-05-25 20:25 ` Stefan Monnier
2021-05-25 21:21 ` Colin Woodbury
2021-05-25 21:29 ` Stefan Monnier
2021-05-25 21:44 ` Colin Woodbury
2021-05-26 7:34 ` Andreas Schwab
2021-05-26 16:31 ` Colin Woodbury
2021-05-26 17:39 ` Andreas Schwab
2021-05-31 1:16 ` Colin Woodbury
2021-06-04 13:08 ` Philipp
[not found] ` <26B660D9-AC76-4AFC-9FFD-2F5D4DCA16C1@acm.org>
2021-06-09 20:54 ` Colin Woodbury
2021-06-09 23:05 ` Stefan Monnier
2021-06-10 0:42 ` Colin Woodbury
2021-06-10 2:45 ` Colin Woodbury [this message]
2021-06-10 7:46 ` Michael Albinus
2021-06-10 14:40 ` Colin Woodbury
2021-06-16 1:15 ` Colin Woodbury
2021-06-19 9:16 ` Michael Albinus
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