Re: org-pdfview-open doesn't work anymore

[Michael Brand <michael.ch.brand@gmail.com>]

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Hi Nicolas

On Fri, Feb 5, 2016 at 6:22 PM, Nicolas Goaziou <mail@nicolasgoaziou.fr> wrote:

> Michael Brand <michael.ch.brand@gmail.com> writes:

>> +      ;; FIXME: Remove this check when most default installations of
>> +      ;; Emacs have at least Org 9.0.
>> +      (let ((arglist (help-function-arglist cmd)))
>> +     (when (or (memq '&optional arglist)
>> +               (memq '&rest arglist)
>> +               (/= 2 (length arglist)))
>> +       (user-error
>> +        (format
>> +         "%s%s%S"
>> +         "Please see Org News for version 9.0 about `org-file-apps', "
>> +         "this function signature is wrong: "
>> +         cmd))))
>
> I have the feeling there is some over-engineering involved there.

Also it should have allowed at least optional arguments

    (when (or (memq
               ;; Too complicated to parse regarding that such functions
               ;; are probably not useful here.
               '&rest
               arglist)
              (/= 2 (length (delete '&optional arglist))))
      (user-error

for e. g. a simple

    (add-to-list 'org-file-apps
                 (cons (concat org-player-file-extensions-regexp "$")
                       'org-player-play-file))

which refers to the existing

    (defun org-player-play-file (filename &optional pos)

> In any case, instead of relying on `help-function-arglist', I suggest to
> use something lightweight:
>
> (condition-case err
>     (funcall ...)
>   (wrong-number-of-arguments
>    (user-error "Please ..."))
>   (invalid-function
>    (user-error "Please ...")))

Of course. I didn't know about this possibility, remixed patch attached.

Michael

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From f1c382cabe5b34f52db22df70d5c25e02de2a18a Mon Sep 17 00:00:00 2001
From: Michael Brand <michael.ch.brand@gmail.com>
Date: Fri, 5 Feb 2016 19:42:55 +0100
Subject: [PATCH] `org-file-apps' add migration hint for function signature

* lisp/org.el (org-open-file): Add an error when the function
signature does not match.
---
 lisp/org.el | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/lisp/org.el b/lisp/org.el
index d4fb8a6..f6c5f89 100644
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -11323,9 +11323,18 @@ If the file does not exist, an error is thrown."
 		  (when (derived-mode-p 'org-mode) (org-reveal)))
 	    (search (org-link-search search))))
      ((functionp cmd)
-      (save-match-data
-	(set-match-data link-match-data)
-	(funcall cmd file link)))
+      (condition-case err
+	  (save-match-data
+	    (set-match-data link-match-data)
+	    (funcall cmd file link))
+	;; FIXME: Remove this check when most default installations of
+	;; Emacs have at least Org 9.0.
+	((wrong-number-of-arguments invalid-function)
+	 (user-error
+	  (concat
+	   "Please see Org News for version 9.0 about `org-file-apps', "
+	   "error: "
+	   (prin1-to-string err))))))
      ((consp cmd)
       ;; FIXME: Remove this check when most default installations of
       ;; Emacs have at least Org 9.0.
@@ -11333,7 +11342,9 @@ If the file does not exist, an error is thrown."
       ;; `org-link-frame-setup' for an old usage of `org-file-apps'
       ;; with sexp instead of a function for `cmd'.
       (user-error
-       "Please see Org News for version 9.0 about `org-file-apps'"))
+       (concat "Please see Org News for version 9.0 about `org-file-apps', "
+	       "error: deprecated usage of "
+	       (prin1-to-string cmd))))
      (t (funcall (cdr (assq 'file org-link-frame-setup)) file)))
     (and (derived-mode-p 'org-mode)
 	 (eq old-mode 'org-mode)
-- 
2.1.3.dirty