master aee0e67a737 2/8: Fix 'eww-read-alternate-url' completion annotations

branch: master
commit aee0e67a73707d14aa005124c478edbc20439030
Author: Eshel Yaron <[email protected]>
Commit: Sean Whitton <[email protected]>

    Fix 'eww-read-alternate-url' completion annotations
    
    The 'annotation-function' used by 'eww-read-alternate-url'
    assumed, for alignment purposes, that completions are shown
    in one column, one completion per line.  But that doesn't
    hold with the default value of 'completions-format'.
    
    This commit fixes the issue by using ':width' space specs
    for alignment instead of ':align-to'.
    
    While we're at it, simplify a bit and switch to an
    'affixation-function', so alignment adapts to the current
    completions (those that match the current input string).
    
    * lisp/net/eww.el: Move 'provide' form to bottom.
    (eww--alternate-urls): Simplify using 'seq-keep'.
    Return propertized strings instead of an alist.
    (eww--alternate-urls-affixation): New function.
    (eww-read-alternate-url): Use it.
---
 lisp/net/eww.el | 119 ++++++++++++++++++++++++++++----------------------------
 1 file changed, 60 insertions(+), 59 deletions(-)

diff --git a/lisp/net/eww.el b/lisp/net/eww.el
index 908df6e3333..a7c7e267583 100644
--- a/lisp/net/eww.el
+++ b/lisp/net/eww.el
@@ -3063,28 +3063,57 @@ Otherwise, the restored buffer will contain a prompt to do so by using
 
 (put 'eww-bookmark-jump 'bookmark-handler-type "EWW")
 
-(provide 'eww)
-
 ;;; Alternate links (RSS and Atom feeds, etc.)
 
 (defun eww--alternate-urls (dom &optional base)
-  "Return an alist of alternate links in DOM.
-
-Each element is a list of the form (URL TYPE TITLE) where URL is
-the href attribute of the link expanded relative to BASE, TYPE is
-its type attribute, and TITLE is its title attribute.  If any of
-these attributes is absent, the corresponding element is nil."
-  (let ((alternates
-         (seq-filter
-          (lambda (attrs) (string= (alist-get 'rel attrs)
-                                   "alternate"))
-          (mapcar #'dom-attributes (dom-by-tag dom 'link)))))
-    (mapcar (lambda (alternate)
-              (list (url-expand-file-name (alist-get 'href alternate)
-                                          base)
-                    (alist-get 'type  alternate)
-                    (alist-get 'title alternate)))
-            alternates)))
+  "Return a list of alternate links in DOM.
+
+Each element is a string URL, which is the the href attribute of the
+link, expanded relative to BASE.  Each URL has text properties \\+`type'
+which is the link's type attribute, and \\+`title', its title attribute."
+  (seq-keep
+   (lambda (link)
+     (let ((attrs (dom-attributes link)))
+       (when (equal (alist-get 'rel attrs) "alternate")
+         (propertize
+          (url-expand-file-name (alist-get 'href attrs) base)
+          'type  (alist-get 'type attrs)
+          'title (or (alist-get 'title attrs) "")))))
+   (dom-by-tag dom 'link)))
+
+(defun eww--alternate-urls-affixation (urls)
+  (let ((url-max-width
+         (seq-max (cons 0 (mapcar #'string-pixel-width urls))))
+        (title-max-width
+         (seq-max
+          (cons 0 (mapcar
+                   (lambda (url)
+                     (string-pixel-width (get-text-property 0 'title url)))
+                   urls))))
+        (sep-width (string-pixel-width " ")))
+    (mapcar
+     (lambda (url)
+       (let ((title (get-text-property 0 'title url)))
+         (list
+          url ""
+          (propertize
+           (concat
+            (propertize
+             " " 'display
+             `( space :width
+                (,(+ sep-width
+                     (- url-max-width (string-pixel-width url))))))
+            title
+            (when-let* ((type (get-text-property 0 'type url)))
+              (concat
+               (propertize
+                " " 'display
+                `( space :width
+                   (,(+ sep-width
+                        (- title-max-width (string-pixel-width title))))))
+               "[" type "]")))
+           'face 'completions-annotations))))
+     urls)))
 
 (defun eww-read-alternate-url ()
   "Get the URL of an alternate link of this page.
@@ -3092,46 +3121,17 @@ these attributes is absent, the corresponding element is nil."
 If there is just one alternate link, return its URL.  If there
 are multiple alternate links, prompt for one in the minibuffer
 with completion.  If there are none, return nil."
-  (when-let* ((alternates (eww--alternate-urls
-                           (plist-get eww-data :dom)
-                           (plist-get eww-data :url))))
-    (let ((url-max-width
-           (seq-max (mapcar #'string-pixel-width
-                            (mapcar #'car alternates))))
-          (title-max-width
-           (seq-max (mapcar #'string-pixel-width
-                            (mapcar #'caddr alternates))))
-          (sep-width (string-pixel-width " ")))
-      (if (cdr alternates)
-            (completing-read
-             "Alternate URL: "
-             (completion-table-with-metadata
-              alternates
-              `((annotation-function
-                 . ,(lambda (feed)
-                      (let* ((attrs (alist-get feed
-                                               alternates
-                                               nil
-                                               nil
-                                               #'string=))
-                             (type (car attrs))
-                             (title (cadr attrs)))
-                        (concat
-                         (propertize " " 'display
-                                     `(space :align-to
-                                             (,(+ sep-width
-                                                  url-max-width))))
-                         title
-                         (when type
-                           (concat
-                            (propertize " " 'display
-                                        `(space :align-to
-                                                (,(+ (* 2 sep-width)
-                                                     url-max-width
-                                                     title-max-width))))
-                            "[" type "]"))))))))
-             nil t)
-        (caar alternates)))))
+  (when-let* ((alts (eww--alternate-urls (plist-get eww-data :dom)
+                                         (plist-get eww-data :url))))
+    (if (cdr alts)
+        ;; Multiple alternate links, prompt the user to select one.
+        (completing-read
+         "Alternate URL: "
+         (completion-table-with-metadata
+          alts `((affixation-function . eww--alternate-urls-affixation)))
+         nil t)
+      ;; Just one alternate link, return it without prompting.
+      (caar alts))))
 
 (defun eww-copy-alternate-url ()
   "Copy the alternate URL of the current page into the kill ring.
@@ -3147,4 +3147,5 @@ version or an RSS feed."
         (message "Copied %s to kill ring" url))
     (user-error "No alternate links found on this page!")))
 
+(provide 'eww)
 ;;; eww.el ends here