Re: [PATCH v5] ol.el: add description format parameter to org-link-parameters

[Hugo Heagren <hugo@heagren.com>]

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Ihor Radchenko <yantar92@gmail.com> writes:

> Currently, the internal implementation will treat nil return value as if
> there was no :default-description and org-link-make-description-function
> were set to nil. We may probably document this. It sounds like a useful
> behavior.

I added some relevant documentation to the `:default-description' part
of the `org-link-parameters' docstring. I also changed the
previosly-failing test to expect the right value. All the tests pass
now.

> Could you also add the proper changelog entry for the test-ol.el
> file?

Think I've got this right now, and other formatting errors.

> unwind-protect is more suitable here and will lead to more concise
> code.

I didn't know about `unwind-protect', thanks! You're right, much better.

> I think that we should also document the new parameter in ORG-NEWS.

Done.

Thanks, Hugo

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From cd5268bc05324140a4cf384ce12b99bba1ddab47 Mon Sep 17 00:00:00 2001
From: Hugo Heagren <hugo@heagren.com>
Date: Mon, 28 Mar 2022 23:18:45 +0100
Subject: [PATCH] ol.el: add description format parameter to
 org-link-parameters

* ol.el (org-link-parameters): Add parameter `:default-description', a
string or a function.
* (org-insert-link): If no description is provided (pre-existing or as
an argument), next option is to use the `:default-description' (if
non-nil) parameter to generate one.

Default descriptions are predictable within a link type, but because
link types are quite diverse, are NOT predictable across many types.
A type-parameter is thus a good place to store information on the
default description.
---
 etc/ORG-NEWS |  7 +++++++
 lisp/ol.el   | 56 +++++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/etc/ORG-NEWS b/etc/ORG-NEWS
index 35af94f92..d51899b20 100644
--- a/etc/ORG-NEWS
+++ b/etc/ORG-NEWS
@@ -322,6 +322,13 @@ purpose of the variable.  The replacement variable
 accepts =listings= and =verbatim= in place of =t= and =nil= (which
 still work, but are no longer listed as valid options).
 
+*** ~org-link-parameters~ has a new ~:default-description~ parameter
+
+The value of ~:default-description~ is used as the initial input when
+prompting for a link description.  It can be a string (used as-is) or
+a function (called with the same arguments as
+~org-make-link-description-function~ to return a string to use).
+
 * Version 9.5
 
 ** Important announcements and breaking changes
diff --git a/lisp/ol.el b/lisp/ol.el
index d4bd0e40c..e568cd6fc 100644
--- a/lisp/ol.el
+++ b/lisp/ol.el
@@ -141,6 +141,18 @@ link.
   Function that inserts a link with completion.  The function
   takes one optional prefix argument.
 
+`:default-description'
+
+  String or function used as a default when prompting users for a
+  link's description.  A string is used as-is, a function is
+  called with two arguments: the full link text, and the
+  description generated by `org-insert-link'.  It should return
+  the description to use (this reflects the behaviour of
+  `org-link-make-description-function').  If it returns nil, no
+  default description is used, but no error is thrown (from the
+  user's perspective, this is equivalent to a default description
+  of \"\").
+
 `:display'
 
   Value for `invisible' text property on the hidden parts of the
@@ -1804,11 +1816,14 @@ prefix negates `org-link-keep-stored-after-insertion'.
 If the LINK-LOCATION parameter is non-nil, this value will be used as
 the link location instead of reading one interactively.
 
-If the DESCRIPTION parameter is non-nil, this value will be used as the
-default description.  Otherwise, if `org-link-make-description-function'
-is non-nil, this function will be called with the link target, and the
-result will be the default link description.  When called non-interactively,
-don't allow to edit the default description."
+If the DESCRIPTION parameter is non-nil, this value will be used
+as the default description.  If not, and the chosen link type has
+a non-nil `:default-description' parameter, that is used to
+generate a description as described in `org-link-parameters'
+docstring. Otherwise, if `org-link-make-description-function' is
+non-nil, this function will be called with the link target, and
+the result will be the default link description.  When called
+non-interactively, don't allow to edit the default description."
   (interactive "P")
   (let* ((wcf (current-window-configuration))
 	 (origbuf (current-buffer))
@@ -1818,7 +1833,10 @@ don't allow to edit the default description."
 	 (desc region)
 	 (link link-location)
 	 (abbrevs org-link-abbrev-alist-local)
-	 entry all-prefixes auto-desc)
+	 (all-prefixes (append (mapcar #'car abbrevs)
+			       (mapcar #'car org-link-abbrev-alist)
+			       (org-link-types)))
+         entry auto-desc type)
     (cond
      (link-location)		      ; specified by arg, just use it.
      ((org-in-regexp org-link-bracket-re 1)
@@ -1859,9 +1877,6 @@ Use TAB to complete link prefixes, then RET for type-specific completion support
 	  (unless (pos-visible-in-window-p (point-max))
 	    (org-fit-window-to-buffer))
 	  (and (window-live-p cw) (select-window cw))))
-      (setq all-prefixes (append (mapcar #'car abbrevs)
-				 (mapcar #'car org-link-abbrev-alist)
-				 (org-link-types)))
       (unwind-protect
 	  ;; Fake a link history, containing the stored links.
 	  (let ((org-link--history
@@ -1893,6 +1908,13 @@ Use TAB to complete link prefixes, then RET for type-specific completion support
       (or entry (push link org-link--insert-history))
       (setq desc (or desc (nth 1 entry)))))
 
+    (setq type
+          (cond
+           ((string-match (rx-to-string `(: string-start (submatch (or ,@all-prefixes)) ":")) link)
+            (match-string 1 link))
+           ((file-name-absolute-p link) "file")
+           ((string-match "\\`\\.\\.?/" link) "file")))
+
     (when (funcall (if (equal complete-file '(64)) 'not 'identity)
 		   (not org-link-keep-stored-after-insertion))
       (setq org-stored-links (delq (assoc link org-stored-links)
@@ -1961,12 +1983,24 @@ Use TAB to complete link prefixes, then RET for type-specific completion support
       (let ((initial-input
 	     (cond
 	      (description)
-	      ((not org-link-make-description-function) desc)
+              (desc)
+              ((org-link-get-parameter type :default-description)
+               (let ((def (org-link-get-parameter type :default-description)))
+                 (condition-case nil
+                     (cond
+                      ((stringp def) def)
+                      ((functionp def)
+                       (funcall def link desc)))
+                   (error
+                    (message "Can't get link description from org link parameter `:default-description': %S"
+			     def)
+		    (sit-for 2)
+                    nil))))
 	      (t (condition-case nil
 		     (funcall org-link-make-description-function link desc)
 		   (error
 		    (message "Can't get link description from %S"
-			     (symbol-name org-link-make-description-function))
+		             org-link-make-description-function)
 		    (sit-for 2)
 		    nil))))))
 	(setq desc (if (called-interactively-p 'any)
-- 
2.20.1


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From 16f4ba5ccb73d09cf9c61eeb67f1ce21c367c043 Mon Sep 17 00:00:00 2001
From: Hugo Heagren <hugo@heagren.com>
Date: Tue, 21 Jun 2022 12:45:50 +0100
Subject: [PATCH] test-ol: tests for default-description param when inserting
 links

* test-ol (test-ol-with-link-parameters-as): Convenience macro for
testing.
(test-ol-insert-link-get-desc): Convenience macro for testing.
(test-ol/return-foobar): Convenience function for testing.
(test-ol/insert-link-default-description): Test for various values of
`:default-description' in `org-link-parameters' (including
`test-ol/return-foobar').
---
 testing/lisp/test-ol.el | 85 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/testing/lisp/test-ol.el b/testing/lisp/test-ol.el
index 429bb52ee..a5bf5758f 100644
--- a/testing/lisp/test-ol.el
+++ b/testing/lisp/test-ol.el
@@ -19,6 +19,8 @@
 
 ;;; Code:
 
+(require 'cl-lib)
+
 \f
 ;;; Decode and Encode Links
 
@@ -625,5 +627,88 @@ See https://github.com/yantar92/org/issues/4."
     (test-ol-parse-link-in-text
         "The <point>http://foo.com/(something)?after=parens link"))))
 
+;;; Insert Links
+
+(defmacro test-ol-with-link-parameters-as (type parameters &rest body)
+  "Pass TYPE/PARAMETERS to `org-link-parameters' and execute BODY.
+
+Save the original value of `org-link-parameters', execute
+`org-link-set-parameters' with the relevant args, execute BODY
+and restore `org-link-parameters'.
+
+TYPE is as in `org-link-set-parameters'.  PARAMETERS is a plist to
+be passed to `org-link-set-parameters'."
+  (let (orig-parameters)
+    ;; Copy all keys in `parameters' and their original values to
+    ;; `orig-parameters'.
+    (cl-loop for param in parameters by 'cddr
+             do (setq orig-parameters
+                      (plist-put orig-parameters param (org-link-get-parameter type param))))
+    `(unwind-protect
+         ;; Set `parameters' values and execute body.
+         (progn (org-link-set-parameters ,type ,@parameters) ,@body)
+       ;; Restore original values.
+       (apply 'org-link-set-parameters ,type ',orig-parameters))))
+
+(defun test-ol-insert-link-get-desc (&optional link-location description)
+  "Insert link in temp buffer, return description.
+
+LINK-LOCATION and DESCRIPTION are passed to
+`org-insert-link' (COMPLETE-FILE is always nil)."
+  (org-test-with-temp-text ""
+    (org-insert-link nil link-location description)
+    (save-match-data
+      (when (and
+             (org-in-regexp org-link-bracket-re 1)
+             (match-end 2))
+        (match-string-no-properties 2)))))
+
+(defun test-ol/return-foobar (_link-test _desc)
+  "Return string \"foobar\".
+
+Take (and ignore) arguments conforming to `:default-description'
+API in `org-link-parameters'.  Used in test
+`test-ol/insert-link-default-description', for the case where
+`:default-description' is a function symbol."
+  "foobar")
+
+(ert-deftest test-ol/insert-link-default-description ()
+  "Test `:default-description' parameter handling."
+  ;; String case.
+  (should
+   (string=
+    "foobar"
+    (test-ol-with-link-parameters-as
+     "id" (:default-description "foobar")
+     (test-ol-insert-link-get-desc "id:foo-bar"))))
+  ;; Lambda case.
+  (should
+   (string=
+    "foobar"
+    (test-ol-with-link-parameters-as
+     "id" (:default-description (lambda (_link-test _desc) "foobar"))
+     (test-ol-insert-link-get-desc "id:foo-bar"))))
+  ;; Function symbol case.
+  (should
+   (string=
+    "foobar"
+    (test-ol-with-link-parameters-as
+     "id" (:default-description #'test-ol/return-foobar)
+     (test-ol-insert-link-get-desc "id:foo-bar"))))
+  ;; `:default-description' parameter is defined, but doesn't return a
+  ;; string.
+  (should
+   (null
+    (test-ol-with-link-parameters-as
+     "id" (:default-description #'ignore)
+     (test-ol-insert-link-get-desc "id:foo-bar"))))
+  ;; Description argument should override `:default-description'.
+  (should
+   (string=
+    "notfoobar"
+    (test-ol-with-link-parameters-as
+     "id" (:default-description "foobar")
+     (test-ol-insert-link-get-desc "id:foo-bar" "notfoobar")))))
+
 (provide 'test-ol)
 ;;; test-ol.el ends here
-- 
2.20.1