bug#68254: EWW ‘readable’ by default

[Jim Porter <jporterbugs@gmail.com>]

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On 1/5/2024 5:35 AM, Eli Zaretskii wrote:
> [Please use Reply All to reply, so that the bug tracker is CC'ed.]
> 
>> Date: Fri, 05 Jan 2024 12:08:29 +0000
>> From: Navajeeth <yvv0@proton.me>
>>
>> I’ve tried that method. While at first it appears to work how I want, it’s sub-optimal because it clutters
>> your history with two version of every webpage you open: one the full non-readable version and then
>> the readable version generated by the after-render-hook. Going back in the history is a chore,
>> you need to press ‘l’ twice to go back one webpage.
>>
>> I used to tolerate it for a while, but now I feel that there could be a better way.

Here's a patch for this. It turns 'eww-readable' into a toggle (using 
the same semantics as minor modes), and also adds an option to prevent 
adding a new history entry for each call.

After this patch, you could set 'eww-readable-adds-to-history' to nil 
and add 'eww-readable' to 'eww-after-render-hook', and then everything 
should work ok. With those settings, you could then call 'eww-readable' 
to display the full page if needed.

(There might be some value in adding another new option that lets you 
specify a list of regexps to match pages that should start in readable 
mode; then it would be easy for users to enable that for 
"https://example\.com/.*" or similar. We can do that later if there's 
any demand for it, though.)

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From 345df3a8f255717a653465513ac9ad9a43c4945f Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Sun, 17 Mar 2024 12:01:59 -0700
Subject: [PATCH] Allow toggling "readable" mode in EWW

Additionally, add an option to prevent adding a new history entry for
each call of 'eww-readable' (bug#68254).

* lisp/net/eww.el (eww-readable-adds-to-history): New option.
(eww-readable): Toggle "readable" mode interactively, like with a minor
mode.  Consult 'eww-readable-adds-to-history'.

* doc/misc/eww.texi (Basics): Describe the new behavior.

* etc/NEWS: Announce this change.
---
 doc/misc/eww.texi |  5 +++++
 etc/NEWS          | 12 ++++++++++++
 lisp/net/eww.el   | 46 ++++++++++++++++++++++++++++++++++++----------
 3 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/doc/misc/eww.texi b/doc/misc/eww.texi
index d31fcf1802b..bec58da3e21 100644
--- a/doc/misc/eww.texi
+++ b/doc/misc/eww.texi
@@ -146,6 +146,11 @@ Basics
 which part of the document contains the ``readable'' text, and will
 only display this part.  This usually gets rid of menus and the like.
 
+When called interactively, this command toggles the display of the
+readable parts.  With a positive prefix argument, always display the
+readable parts, and with a zero or negative prefix, display the full
+page.
+
 @findex eww-toggle-fonts
 @vindex shr-use-fonts
 @kindex F
diff --git a/etc/NEWS b/etc/NEWS
index b02712dd21c..b23754fb17f 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1054,6 +1054,18 @@ entries newer than the current page.  To change the behavior when
 browsing from "historical" pages, you can customize
 'eww-before-browse-history-function'.
 
++++
+*** 'eww-readable' now toggles display of the readable parts of a web page.
+When called interactively, 'eww-readable' toggles whether to display
+only the readable parts of a page or the full page.  With a positive
+prefix argument, always display the readable parts, and with a zero or
+negative prefix, always display the full page.
+
+---
+*** New option 'eww-readable-adds-to-history'.
+When non-nil (the default), calling 'eww-readable' adds a new entry to
+the EWW page history.
+
 ** go-ts-mode
 
 +++
diff --git a/lisp/net/eww.el b/lisp/net/eww.el
index 54847bdf396..305357f8f2f 100644
--- a/lisp/net/eww.el
+++ b/lisp/net/eww.el
@@ -275,6 +275,11 @@ eww-url-transformers
   :type '(repeat function)
   :version "29.1")
 
+(defcustom eww-readable-adds-to-history t
+  "If non-nil, calling `eww-readable' adds a new entry to the history."
+  :type 'boolean
+  :version "30.1")
+
 (defface eww-form-submit
   '((((type x w32 ns haiku pgtk android) (class color))	; Like default mode line
      :box (:line-width 2 :style released-button)
@@ -1055,14 +1060,31 @@ eww-toggle-paragraph-direction
                "automatic"
              bidi-paragraph-direction)))
 
-(defun eww-readable ()
-  "View the main \"readable\" parts of the current web page.
+(defun eww-readable (&optional arg)
+  "Toggle display of only the main \"readable\" parts of the current web page.
 This command uses heuristics to find the parts of the web page that
-contains the main textual portion, leaving out navigation menus and
-the like."
-  (interactive nil eww-mode)
+contains the main textual portion, leaving out navigation menus and the
+like.
+
+If called interactively, toggle the display of the readable parts.  If
+the prefix argument is positive, display the readable parts, and if it
+is zero or negative, display the full page.
+
+If called from Lisp, toggle the display of the readable parts if ARG is
+`toggle'.  Display the readable parts if ARG is nil, omitted, or is a
+positive number.  Display the full page if ARG is a negative number."
+  (interactive (list (if current-prefix-arg
+                         (prefix-numeric-value current-prefix-arg)
+                       'toggle))
+               eww-mode)
   (let* ((old-data eww-data)
-	 (dom (with-temp-buffer
+	 (make-readable (cond
+                         ((eq arg 'toggle)
+                          (not (plist-get old-data :readable)))
+                         ((and (numberp arg) (< arg 1))
+                          nil)
+                         (t t)))
+         (dom (with-temp-buffer
 		(insert (plist-get old-data :source))
 		(condition-case nil
 		    (decode-coding-region (point-min) (point-max) 'utf-8)
@@ -1071,14 +1093,18 @@ eww-readable
 		(libxml-parse-html-region (point-min) (point-max))))
          (base (plist-get eww-data :url)))
     (eww-score-readability dom)
-    (eww-save-history)
-    (eww--before-browse)
+    (when eww-readable-adds-to-history
+      (eww-save-history)
+      (eww--before-browse))
     (eww-display-html nil nil
-                      (list 'base (list (cons 'href base))
-                            (eww-highest-readability dom))
+                      (if make-readable
+                          (list 'base (list (cons 'href base))
+                                (eww-highest-readability dom))
+                        dom)
 		      nil (current-buffer))
     (dolist (elem '(:source :url :title :next :previous :up :peer))
       (plist-put eww-data elem (plist-get old-data elem)))
+    (plist-put eww-data :readable make-readable)
     (eww--after-page-change)))
 
 (defun eww-score-readability (node)
-- 
2.25.1