org-eww.el: Special kill in eww for Org for keeping the links

* contrib/lisp/org-eww.el(org-eww-copy-for-org-mode): Realization of
  the kill.
  (org-eww-goto-next-url-property-change,
  org-eww-no-next-link-p, org-eww-url-below-point): Auxiliaries
  for accessing a eww buffer
  (org-eww-extend-eww-keymap): Add the new kill to eww keymap

The code has emerged from the very similar org-w3m.el.

contrib/lisp/org-eww.el

@@ -1,4 +1,4 @@
-;;; org-eww.el --- Storing link in eww-mode for Org-mode
+;;; org-eww.el --- Store url and kill from Eww mode for Org
 
 ;; Copyright (C) 2014 Free Software Foundation, Inc.
 
@@ -27,17 +27,27 @@
 ;; When this module is active `org-store-link' (often on key C-c l) in
 ;; a eww buffer stores a link to the current url of the eww buffer.
 
-;; `org-eww-store-link' below is almost the same as
-;; `org-w3m-store-link' of the org-w3m module.
+;; In an eww buffer function `org-eww-copy-for-org-mode' kills either
+;; a region or the whole buffer if no region is set and transforms the
+;; text on the fly so that it can be pasted into an org-mode buffer
+;; with hot links.
 
-;; Hint: There are further features in module org-w3m which might be
-;; interesting for org-eww also.
+;; C-c C-x C-w (and also C-c C-x M-w) trigger
+;; `org-eww-copy-for-org-mode'.
+
+;; Hint: A lot of code of this module comes from module org-w3m which
+;; has been written by Andy Steward based on the idea of Richard
+;; Riley.  Thanks!
+
+;; Potential: Since the code for w3m and eww is so similar one could
+;; try to refactor.
 
 
 ;;; Code:
-
 (require 'org)
 
+
+;; Store Org-link in eww-mode buffer
 (add-hook 'org-store-link-functions 'org-eww-store-link)
 (defun org-eww-store-link ()
   "Store a link to the url of a eww buffer."
@@ -48,6 +58,99 @@
      :url (url-view-url t)
      :description (or eww-current-title eww-current-url))))
 
+
+;; Some auxiliary functions concerning links in eww buffers
+(defun org-eww-goto-next-url-property-change ()
+  "Move cursor to the start of next link if exists.  Else no
+move.  Return point."
+  (goto-char
+   (or (next-single-property-change (point) 'shr-url)
+       (point))))
+
+(defun org-eww-no-next-link-p ()
+  "Whether there is no next link after the cursor.
+Return t if there is no next link; otherwise, return nil."
+  (save-excursion
+    (and (eq (point) (org-eww-goto-next-url-property-change)) t)))
+
+(defun org-eww-url-below-point ()
+  "Return the url below point if there is an url; otherwise, return nil."
+  (get-text-property (point) 'shr-url))
+
+
+(defun org-eww-copy-for-org-mode ()
+  "Copy current buffer content or active region with `org-mode' style links.
+This will encode `link-title' and `link-location' with
+`org-make-link-string', and insert the transformed test into the kill ring,
+so that it can be yanked into an Org-mode buffer with links working correctly."
+  (interactive)
+  (let* ((regionp (org-region-active-p))
+         (transform-start (point-min))
+         (transform-end (point-max))
+         return-content
+         link-location link-title
+         temp-position out-bound)
+    (when regionp
+      (setq transform-start (region-beginning))
+      (setq transform-end (region-end))
+      ;; Deactivate mark if current mark is activate.
+      (if (fboundp 'deactivate-mark) (deactivate-mark)))
+    (message "Transforming links...")
+    (save-excursion
+      (goto-char transform-start)
+      (while (and (not out-bound)                 ; still inside region to copy
+                  (not (org-eww-no-next-link-p))) ; there is a next link
+        ;; store current point before jump next anchor
+        (setq temp-position (point))
+        ;; move to next anchor when current point is not at anchor
+        (or (org-eww-url-below-point)
+	    (org-eww-goto-next-url-property-change))
+	(assert (org-eww-url-below-point) t
+                "program logic error: point must have an url below but it hasn't")
+	(if (<= (point) transform-end)  ; if point is inside transform bound
+	    (progn
+	      ;; get content between two links.
+	      (if (> (point) temp-position)
+		  (setq return-content (concat return-content
+					       (buffer-substring
+						temp-position (point)))))
+	      ;; get link location at current point.
+	      (setq link-location (org-eww-url-below-point))
+	      ;; get link title at current point.
+	      (setq link-title
+		    (buffer-substring
+		     (point)
+		     (org-eww-goto-next-url-property-change)))
+              ;; concat `org-mode' style url to `return-content'.
+              (setq return-content (concat return-content
+                                           (org-make-link-string
+                                            link-location link-title))))
+	  (goto-char temp-position)     ; reset point before jump next anchor
+	  (setq out-bound t)            ; for break out `while' loop
+	  ))
+      ;; add the rest until end of the region to be copied
+      (if (< (point) transform-end)
+          (setq return-content
+                (concat return-content
+                        (buffer-substring (point) transform-end))))
+      (org-kill-new return-content)
+      (message "Transforming links...done, use C-y to insert text into Org-mode file"))))
+
+
+;; Additional keys for eww-mode
+
+(defun org-eww-extend-eww-keymap ()
+  (define-key eww-mode-map "\C-c\C-x\M-w" 'org-eww-copy-for-org-mode)
+  (define-key eww-mode-map "\C-c\C-x\C-w" 'org-eww-copy-for-org-mode))
+
+(when (and (boundp 'eww-mode-map)
+           (keymapp eww-mode-map)) ; eww is already up.
+  (org-eww-extend-eww-keymap))
+
+(add-hook
+ 'eww-mode-hook
+ (lambda () (org-eww-extend-eww-keymap)))
+
 
 (provide 'org-eww)