X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=elopher.el;h=0dab9d37a3341e3f76db2db821113fcda84267a0;hb=656ccc1872169c9a8de6870a075ae5865f1725ef;hp=96cd641252de05d4d5b6dc8a9c9996d025b41904;hpb=a2908980269da9ee2fea47b1065fd71eb2596902;p=elpher.git

diff --git a/elopher.el b/elopher.el
index 96cd641..0dab9d3 100644
--- a/elopher.el
+++ b/elopher.el
@@ -1,312 +1,636 @@
-;;; elopher.el --- gopher client
+;;; elopher.el --- elisp gopher client
 
 ;;; Commentary:
 
-;; Simple gopher client in elisp.
+;; An elisp gopher client.
 
 ;;; Code:
 
+;;; Global constants
+;;
+
+(defconst elopher-version "1.0.0"
+  "Current version of elopher.")
+
+(defconst elopher-margin-width 6
+  "Width of left-hand margin used when rendering indicies.")
+
+(defconst elopher-start-index
+  (mapconcat
+   'identity
+   (list "i\tfake\tfake\t1"
+         "i--------------------------------------------\tfake\tfake\t1"
+         "i          Elopher Gopher Client             \tfake\tfake\t1"
+         (format "i              version %s\tfake\tfake\t1" elopher-version)
+         "i--------------------------------------------\tfake\tfake\t1"
+         "i\tfake\tfake\t1"
+         "iBasic usage:\tfake\tfake\t1"
+         "i\tfake\tfake\t1"
+         "i - tab/shift-tab: next/prev directory entry on current page\tfake\tfake\t1"
+         "i - RET/mouse-1: open directory entry under cursor\tfake\tfake\t1"
+         "i - u: return to parent directory entry\tfake\tfake\t1"
+         "i - g: go to a particular page\tfake\tfake\t1"
+         "i - r: redraw current page (using cached contents if available)\tfake\tfake\t1"
+         "i - R: reload current page (regenerates cache)\tfake\tfake\t1"
+         "i - d: download directory entry under cursor\tfake\tfake\t1"
+         "i - w: display the raw server response for the current page\tfake\tfake\t1"
+         "i\tfake\tfake\t1"
+         "iPlaces to start exploring Gopherspace:\tfake\tfake\t1"
+         "i\tfake\tfake\t1"
+         "1Floodgap Systems Gopher Server\t\tgopher.floodgap.com\t70"
+         "i\tfake\tfake\t1"
+         "iAlternatively, select the following item and enter some\tfake\tfake\t1"
+         "isearch terms:\tfake\tfake\t1"
+         "i\tfake\tfake\t1"
+         "7Veronica-2 Gopher Search Engine\t/v2/vs\tgopher.floodgap.com\t70"
+         ".")
+   "\r\n")
+  "Source for elopher start page.")
+
+
 ;;; Customization group
 ;;
 
 (defgroup elopher nil
-  "A simple gopher client."
+  "A gopher client."
   :group 'applications)
 
-(defcustom elopher-index-face '(foreground-color . "cyan")
+(defface elopher-index
+  '((((background dark)) :foreground "deep sky blue")
+    (((background light)) :foreground "blue"))
   "Face used for index records.")
-(defcustom elopher-text-face '(foreground-color . "white")
+
+(defface elopher-text
+  '((((background dark)) :foreground "white")
+    (((background light)) :weight bold))
   "Face used for text records.")
-(defcustom elopher-info-face '(foreground-color . "gray")
+
+(defface elopher-info '()
   "Face used for info records.")
-(defcustom elopher-image-face '(foreground-color . "green")
+
+(defface elopher-image
+  '((((background dark)) :foreground "green")
+    (t :foreground "dark green"))
   "Face used for image records.")
-(defcustom elopher-unknown-face '(foreground-color . "red")
+
+(defface elopher-search
+  '((((background light)) :foreground "orange")
+    (((background dark)) :foreground "dark orange"))
+  "Face used for search records.")
+
+(defface elopher-url
+  '((((background dark)) :foreground "yellow")
+    (((background light)) :foreground "dark red"))
+  "Face used for url records.")
+
+(defface elopher-binary
+  '((t :foreground "magenta"))
+  "Face used for binary records.")
+
+(defface elopher-unknown
+  '((t :foreground "red"))
   "Face used for unknown record types.")
 
+(defface elopher-margin-key
+  '((((background dark)) :foreground "white"))
+  "Face used for margin key.")
+
+(defface elopher-margin-brackets
+  '((t :foreground "blue"))
+  "Face used for brackets around margin key.")
+
+(defcustom elopher-open-urls-with-eww nil
+  "If non-nil, open URL selectors using eww.
+Otherwise, use the system browser via the BROWSE-URL function."
+  :type '(boolean))
+
 ;;; Model
 ;;
 
-(defun elopher-make-node (parent address &optional content)
-  (list parent address cache))
+;; Address
 
-(defun elopher-node-parent (node)
-  (car node))
+(defun elopher-make-address (selector host port)
+  "Create an address of a gopher object with SELECTOR, HOST and PORT."
+  (list selector host port))
 
-(defun elopher-node-address (node)
-  (cadr node))
+(defun elopher-address-selector (address)
+  "Retrieve selector from ADDRESS."
+  (car address))
 
-(defun elopher-node-content (node)
-  (caddr node))
+(defun elopher-address-host (address)
+  "Retrieve host from ADDRESS."
+  (cadr address))
 
-(defun elopher-reload-node (node after)
-  ())
+(defun elopher-address-port (address)
+  "Retrieve port from ADDRESS."
+  (caddr address))
 
-;;; Global constants
-;;
+;; Node
 
-(defconst elopher-version "1.0.0"
-  "Current version of elopher.")
+(defun elopher-make-node (parent address getter &optional content pos)
+  "Create a node in the gopher page hierarchy.
 
-(defconst elopher-margin-width 6
-  "Width of left-hand margin used when rendering indicies.")
+PARENT specifies the parent of the node, ADDRESS specifies the address of
+the gopher page, GETTER provides the getter function used to obtain this
+page.
 
-(defconst elopher-start-page
-  (concat "i\tfake\tfake\t1\r\n"
-          "i--------------------------------------------\tfake\tfake\t1\r\n"
-          "i          Elopher Gopher Client             \tfake\tfake\t1\r\n"
-          (format "i              version %s\tfake\tfake\t1\r\n" elopher-version)
-          "i--------------------------------------------\tfake\tfake\t1\r\n"
-          "i\tfake\tfake\t1\r\n"
-          "iBasic usage:\tfake\tfake\t1\r\n"
-          "i - tab/shift-tab: next/prev directory entry\tfake\tfake\t1\r\n"
-          "i - RET/mouse-1: open directory entry\tfake\tfake\t1\r\n"
-          "i - u: return to parent directory entry\tfake\tfake\t1\r\n"
-          "i - g: go to a particular site\tfake\tfake\t1\r\n"
-          "i\tfake\tfake\t1\r\n"
-          "iPlaces to start exploring Gopherspace:\tfake\tfake\t1\r\n"
-          "1Floodgap Systems Gopher Server\t\tgopher.floodgap.com\t70\r\n"
-          "1Super-Dimensional Fortress\t\tsdf.org\t70\r\n"
-          "i\tfake\tfake\t1\r\n"
-          "iTest entries:\tfake\tfake\t1\r\n"
-          "pXKCD comic image\t/fun/xkcd/comics/2130/2137/text_entry.png\tgopher.floodgap.com\t70\r\n"))
+The optional arguments CONTENT and POS can be used to fill the cached
+content and cursor position fields of the node."
+  (list parent address getter content pos))
 
-;;; Mode and keymap
-;;
+(defun elopher-node-parent (node)
+  "Retrieve the parent node of NODE."
+  (elt node 0))
 
-(setq elopher-mode-map
-  (let ((map (make-sparse-keymap)))
-    (define-key map (kbd "<tab>") 'elopher-next-link)
-    (define-key map (kbd "<S-tab>") 'elopher-prev-link)
-    (define-key map (kbd "u") 'elopher-pop-history)
-    (define-key map (kbd "g") 'elopher-go)
-    (define-key map (kbd "r") 'elopher-reload)
-    (when (require 'evil nil t)
-      (evil-define-key 'normal map
-        (kbd "C-]") 'elopher-follow-closest-link
-        (kbd "C-t") 'elopher-pop-history
-        (kbd "u") 'elopher-pop-history
-        (kbd "g") 'elopher-go
-        (kbd "r") 'elopher-reload))
-    map))
-  ;; "Keymap for gopher client.")
+(defun elopher-node-address (node)
+  "Retrieve the address of NODE."
+  (elt node 1))
 
-(define-derived-mode elopher-mode special-mode "elopher"
-  "Major mode for elopher, an elisp gopher client.")
+(defun elopher-node-getter (node)
+  "Retrieve the preferred getter function of NODE."
+  (elt node 2))
+
+(defun elopher-node-content (node)
+  "Retrieve the cached content of NODE, or nil if none exists."
+  (elt node 3))
+
+(defun elopher-node-pos (node)
+  "Retrieve the cached cursor position for NODE, or nil if none exists."
+  (elt node 4))
+
+(defun elopher-set-node-content (node content)
+  "Set the content cache of NODE to CONTENT."
+  (setcar (nthcdr 3 node) content))
+
+(defun elopher-set-node-pos (node pos)
+  "Set the cursor position cache of NODE to POS."
+  (setcar (nthcdr 4 node) pos))
+
+(defun elopher-save-pos ()
+  "Save the current position of point to the current node."
+  (when elopher-current-node
+    (elopher-set-node-pos elopher-current-node (point))))
+
+(defun elopher-restore-pos ()
+  "Restore the position of point to that cached in the current node."
+  (let ((pos (elopher-node-pos elopher-current-node)))
+    (if pos
+        (goto-char pos)
+      (goto-char (point-min)))))
+
+;; Node graph traversal
+
+(defvar elopher-current-node)
+
+(defun elopher-visit-node (node &optional getter)
+  "Visit NODE using its own getter or GETTER, if non-nil."
+  (elopher-save-pos)
+  (elopher-process-cleanup)
+  (setq elopher-current-node node)
+  (if getter
+      (funcall getter)
+    (funcall (elopher-node-getter node))))
+
+(defun elopher-visit-parent-node ()
+  "Visit the parent of the current node."
+  (let ((parent-node (elopher-node-parent elopher-current-node)))
+    (when parent-node
+      (elopher-visit-node parent-node))))
+      
+(defun elopher-reload-current-node ()
+  "Reload the current node, discarding any existing cached content."
+  (elopher-set-node-content elopher-current-node nil)
+  (elopher-visit-node elopher-current-node))
+
+;;; Buffer preparation
+;;
 
+(defmacro elopher-with-clean-buffer (&rest args)
+  "Evaluate ARGS with a clean *elopher* buffer as current."
+  (list 'progn
+        '(switch-to-buffer "*elopher*")
+        '(elopher-mode)
+        (append (list 'let '((inhibit-read-only t))
+                      '(erase-buffer))
+                args)))
 
 ;;; Index rendering
 ;;
 
 (defun elopher-insert-index (string)
-  "Inserts the index corresponding to STRING into the current buffer."
+  "Insert the index corresponding to STRING into the current buffer."
   (dolist (line (split-string string "\r\n"))
-    (elopher-insert-index-record line)))
+    (unless (= (length line) 0)
+      (elopher-insert-index-record line))))
 
 (defun elopher-insert-margin (&optional type-name)
+  "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
   (if type-name
-      (insert (format (concat "%" (number-to-string elopher-margin-width) "s"
-                              (concat
-                               (propertize "[" 'face '(foreground-color . "blue"))
-                               (propertize type-name 'face '(foreground-color . "white"))
-                               (propertize "]" 'face '(foreground-color . "blue"))))))
+      (progn
+        (insert (format (concat "%" (number-to-string (- elopher-margin-width 1)) "s")
+                        (concat
+                         (propertize "[" 'face 'elopher-margin-brackets)
+                         (propertize type-name 'face 'elopher-margin-key)
+                         (propertize "]" 'face 'elopher-margin-brackets))))
+        (insert " "))
     (insert (make-string elopher-margin-width ?\s))))
 
+(defvar elopher-type-map
+  '((?0 elopher-get-text-node "T" elopher-text)
+    (?1 elopher-get-index-node "/" elopher-index)
+    (?g elopher-get-image-node "im" elopher-image)
+    (?p elopher-get-image-node "im" elopher-image)
+    (?I elopher-get-image-node "im" elopher-image)
+    (?4 elopher-get-node-download "B" elopher-binary)
+    (?5 elopher-get-node-download "B" elopher-binary)
+    (?9 elopher-get-node-download "B" elopher-binary)
+    (?7 elopher-get-search-node "?" elopher-search))
+  "Association list from types to getters, margin codes and index faces.")
+
 (defun elopher-insert-index-record (line)
-  "Inserts the index record corresponding to LINE into the current buffer."
+  "Insert the index record corresponding to LINE into the current buffer."
   (let* ((type (elt line 0))
          (fields (split-string (substring line 1) "\t"))
          (display-string (elt fields 0))
          (selector (elt fields 1))
-         (hostname (elt fields 2))
+         (host (elt fields 2))
          (port (elt fields 3))
-         (address (list selector hostname port)))
-    (pcase type
-      (?i (elopher-insert-margin)
-          (insert (propertize display-string
-                              'face elopher-info-face)))
-      (?0 (elopher-insert-margin "T")
-          (insert-text-button display-string
-                              'face elopher-text-face
-                              'link-getter #'elopher-get-text
-                              'link-address address
-                              'action #'elopher-click-link
-                              'follow-link t))
-      (?1 (elopher-insert-margin "/")
+         (address (elopher-make-address selector host port))
+         (type-map-entry (alist-get type elopher-type-map)))
+    (if type-map-entry
+        (let ((getter (car type-map-entry))
+              (margin-code (cadr type-map-entry))
+              (face (caddr type-map-entry)))
+          (elopher-insert-margin margin-code)
           (insert-text-button display-string
-                              'face elopher-index-face
-                              'link-getter #'elopher-get-index
-                              'link-address address
+                              'face face
+                              'elopher-node (elopher-make-node elopher-current-node
+                                                               address
+                                                               getter)
                               'action #'elopher-click-link
-                              'follow-link t))
-      (?p (elopher-insert-margin "img")
-          (insert-text-button display-string
-                             'face elopher-image-face
-                             'link-getter #'elopher-get-image
-                             'link-address address
-                             'action #'elopher-click-link
-                             'follow-link t))
-      (?.) ; Occurs at end of index, can safely ignore.
-      (tp (elopher-insert-margin (concat (char-to-string tp) "?"))
-          (insert (propertize display-string
-                              'face elopher-unknown-face))))
+                              'follow-link t
+                              'help-echo (format "mouse-1, RET: open %s on %s port %s"
+                                                 selector host port)))
+      (pcase type
+        (?i (elopher-insert-margin) ; Information
+            (insert (propertize display-string
+                                'face 'elopher-info)))
+        (?h (elopher-insert-margin "W") ; Web link
+            (let ((url (elt (split-string selector "URL:") 1)))
+              (insert-text-button display-string
+                                  'face 'elopher-url
+                                  'elopher-url url
+                                  'action #'elopher-click-url
+                                  'follow-link t
+                                  'help-echo (format "mouse-1, RET: open url %s" url))))
+        (?.) ; Occurs at end of index, can safely ignore.
+        (tp (elopher-insert-margin (concat (char-to-string tp) "?"))
+            (insert (propertize display-string
+                                'face 'elopher-unknown-face)))))
     (insert "\n")))
 
-;;; History management
-;;
-
-(defvar elopher-history nil
-  "List of pages in elopher history.")
-
-(defvar elopher-place-history nil
-  "List of objects describing how to access pages in history.")
-
-(defvar elopher-current-place nil
-  "How to access current page.")
-
-(defun elopher-push-history ()
-  "Add current contents of buffer, including point, to history."
-  (unless (string-empty-p (buffer-string))
-    (push
-     (list (buffer-string)
-           (point))
-     elopher-history)
-    (push
-     elopher-current-place
-     elopher-place-history)))
-
-(defun elopher-pop-history ()
-  "Restore most recent page from history."
-  (interactive)
-  (if (get-buffer "*elopher*")
-      (if elopher-history
-          (let* ((inhibit-read-only t)
-                 (prev-page (pop elopher-history))
-                 (page-string (car prev-page))
-                 (page-point (cadr prev-page)))
-            (switch-to-buffer "*elopher*")
-            (erase-buffer)
-            (insert page-string)
-            (goto-char page-point)
-            (setq elopher-current-place (pop elopher-place-history)))
-        (message "Already at start of history."))
-    (message "No elopher buffer found.")))
-
 
 ;;; Selector retrieval (all kinds)
 ;;
 
-(defun elopher-get-selector (selector host port filter &optional sentinel)
-  (switch-to-buffer "*elopher*")
-  (elopher-mode)
-  (elopher-push-history)
-  (let ((inhibit-read-only t))
-    (erase-buffer))
+(defun elopher-process-cleanup ()
+  "Immediately shut down any extant elopher process."
+  (let ((p (get-process "elopher-process")))
+    (if p (delete-process p))))
+
+(defvar elopher-selector-string)
+
+(defun elopher-get-selector (address after)
+  "Retrieve selector specified by ADDRESS, then execute AFTER.
+The result is stored as a string in the variable elopher-selector-string."
+  (setq elopher-selector-string "")
   (make-network-process
    :name "elopher-process"
-   :host host
-   :service (if port port 70)
-   :filter filter
-   :sentinel sentinel)
-  (process-send-string "elopher-process" (concat selector "\n")))
+   :host (elopher-address-host address)
+   :service (elopher-address-port address)
+   :filter (lambda (proc string)
+             (setq elopher-selector-string (concat elopher-selector-string string)))
+   :sentinel after)
+  (process-send-string "elopher-process"
+                       (concat (elopher-address-selector address) "\n")))
 
 ;; Index retrieval
 
-(defun elopher-index-filter (proc string)
-  (let ((marker (process-mark proc))
-        (inhibit-read-only t))
-    (if (not (marker-position marker))
-        (set-marker marker 0 (current-buffer)))
-    (save-excursion
-      (goto-char marker)
-      (elopher-render-complete-records string)
-      (set-marker marker (point)))))
-
-(defun elopher-get-index (selector host port)
-  (setq elopher-incomplete-record "")
-  (elopher-get-selector selector host port
-                        #'elopher-index-filter))
+(defun elopher-get-index-node ()
+  "Getter which retrieves the current node contents as an index."
+  (let ((content (elopher-node-content elopher-current-node))
+        (address (elopher-node-address elopher-current-node)))
+    (if content
+        (progn
+          (elopher-with-clean-buffer
+           (insert content))
+          (elopher-restore-pos))
+      (if address
+          (progn
+            (elopher-with-clean-buffer
+             (insert "LOADING DIRECTORY..."))
+            (elopher-get-selector address
+                                  (lambda (proc event)
+                                    (unless (string-prefix-p "deleted" event)
+                                      (elopher-with-clean-buffer
+                                       (elopher-insert-index elopher-selector-string))
+                                      (elopher-restore-pos)
+                                      (elopher-set-node-content elopher-current-node
+                                                                (buffer-string))))))
+        (progn
+          (elopher-with-clean-buffer
+           (elopher-insert-index elopher-start-index))
+          (elopher-restore-pos)
+          (elopher-set-node-content elopher-current-node
+                                    (buffer-string)))))))
 
 ;; Text retrieval
 
-(defun elopher-text-filter (proc string)
-  (let ((marker (process-mark proc))
-        (inhibit-read-only t))
-    (if (not (marker-position marker))
-        (set-marker marker 0 (current-buffer)))
-    (save-excursion
-      (goto-char marker)
-      (dolist (line (split-string string "\r"))
-        (insert line))
-      (set-marker marker (point)))))
-
-(defun elopher-get-text (selector host port)
-  (elopher-get-selector selector host port
-                        #'elopher-text-filter))
+(defconst elopher-url-regex
+  "\\(https?\\|gopher\\)://\\([a-zA-Z0-9.\-]+\\)\\(?3::[0-9]+\\)?\\(?4:/[^ \r\n\t(),]*\\)?"
+  "Regexp used to locate and buttinofy URLs in text files loaded by elopher.")
+
+(defun elopher-buttonify-urls (string)
+  "Turn substrings which look like urls in STRING into clickable buttons."
+  (with-temp-buffer
+    (insert string)
+    (goto-char (point-min))
+    (while (re-search-forward elopher-url-regex nil t)
+      (let ((url (match-string 0))
+            (protocol (downcase (match-string 1))))
+        (if (string= protocol "gopher")
+            (let* ((host (match-string 2))
+                   (port 70)
+                   (type-and-selector (match-string 4))
+                   (type (if (> (length type-and-selector) 1)
+                             (elt type-and-selector 1)
+                           ?1))
+                   (selector (if (> (length type-and-selector) 1)
+                                 (substring type-and-selector 2)
+                               ""))
+                   (address (elopher-make-address selector host port))
+                   (getter (car (alist-get type elopher-type-map))))
+              (make-text-button (match-beginning 0)
+                                (match-end 0)
+                                'elopher-node (elopher-make-node elopher-current-node
+                                                                 address
+                                                                 getter)
+                                'action #'elopher-click-link
+                                'follow-link t
+                                'help-echo (format "mouse-1, RET: open %s on %s port %s"
+                                                   selector host port)))
+          (make-text-button (match-beginning 0)
+                            (match-end 0)
+                            'elopher-url url
+                            'action #'elopher-click-url
+                            'follow-link t
+                            'help-echo (format "mouse-1, RET: open url %s" url)))))
+    (buffer-string)))
+
+(defun elopher-process-text (string)
+  "Remove CRs and trailing period from the gopher text document STRING."
+  (let* ((chopped-str (replace-regexp-in-string "\r\n\.\r\n$" "\r\n" string))
+         (cleaned-str (replace-regexp-in-string "\r" "" chopped-str)))
+    (elopher-buttonify-urls cleaned-str)))
+
+(defun elopher-get-text-node ()
+  "Getter which retrieves the current node contents as a text document."
+  (let ((content (elopher-node-content elopher-current-node))
+        (address (elopher-node-address elopher-current-node)))
+    (if content
+        (progn
+          (elopher-with-clean-buffer
+           (insert content))
+          (elopher-restore-pos))
+      (progn
+        (elopher-with-clean-buffer
+         (insert "LOADING TEXT..."))
+        (elopher-get-selector address
+                              (lambda (proc event)
+                                (unless (string-prefix-p "deleted" event)
+                                  (elopher-with-clean-buffer
+                                   (insert (elopher-process-text elopher-selector-string)))
+                                  (elopher-restore-pos)
+                                  (elopher-set-node-content elopher-current-node
+                                                            (buffer-string)))))))))
 
 ;; Image retrieval
 
-(defvar elopher-image-buffer "")
-
-(defun elopher-image-filter (proc string)
-  (setq elopher-image-buffer (concat elopher-image-buffer string)))
-
-(defun elopher-image-sentinel (proc event)
-  (let ((inhibit-read-only t))
-    (insert-image (create-image elopher-image-buffer))))
-
-(defun elopher-get-image (selector host port)
-  (setq elopher-image-buffer "")
-  (elopher-get-selector selector host port
-                        #'elopher-image-filter
-                        #'elopher-image-sentinel))
-
-;; Start page retrieval
-
-(defun elopher-get-start-page (&optional selector host port)
-  "Display start page.  SELECTOR, HOST and PORT are unused."
-  (let ((inhibit-read-only t))
-    (erase-buffer)
-    (save-excursion
-      (elopher-render-complete-records elopher-start-page))))
-
-;;; Navigation methods
+(defun elopher-get-image-node ()
+  "Getter which retrieves the current node contents as an image to view."
+  (let ((content (elopher-node-content elopher-current-node))
+        (address (elopher-node-address elopher-current-node)))
+    (if content
+        (progn
+          (elopher-with-clean-buffer
+           (insert-image content))
+          (setq cursor-type nil)
+          (elopher-restore-pos))
+      (progn
+        (elopher-with-clean-buffer
+         (insert "LOADING IMAGE..."))
+        (elopher-get-selector address
+                              (lambda (proc event)
+                                (unless (string-prefix-p "deleted" event)
+                                  (let ((image (create-image
+                                                (encode-coding-string elopher-selector-string
+                                                                      'no-conversion)
+                                                nil t)))
+                                    (elopher-with-clean-buffer
+                                     (insert-image image))
+                                    (setq cursor-type nil)
+                                    (elopher-restore-pos)
+                                    (elopher-set-node-content elopher-current-node
+                                                              image)))))))))
+
+;; Search retrieval
+
+(defun elopher-get-search-node ()
+  "Getter which submits a search query to the address of the current node."
+  (let ((content (elopher-node-content elopher-current-node))
+        (address (elopher-node-address elopher-current-node))
+        (aborted t))
+    (if content
+        (progn
+          (elopher-with-clean-buffer
+           (insert content))
+          (elopher-restore-pos)
+          (message "Displaying cached search results.  Reload to perform a new search."))
+      (unwind-protect
+          (let* ((query-string (read-string "Query: "))
+                 (query-selector (concat (elopher-address-selector address) "\t" query-string))
+                 (search-address (elopher-make-address query-selector
+                                                       (elopher-address-host address)
+                                                       (elopher-address-port address))))
+            (setq aborted nil)
+            (elopher-with-clean-buffer
+             (insert "LOADING RESULTS..."))
+            (elopher-get-selector search-address
+                                  (lambda (proc event)
+                                    (unless (string-prefix-p "deleted" event)
+                                      (elopher-with-clean-buffer
+                                       (elopher-insert-index elopher-selector-string))
+                                      (goto-char (point-min))
+                                      (elopher-set-node-content elopher-current-node
+                                                                (buffer-string))))))
+        (if aborted
+            (elopher-visit-parent-node))))))
+
+;; Raw server response retrieval
+
+(defun elopher-get-node-raw ()
+  "Getter which retrieves the raw server response for the current node."
+  (let* ((content (elopher-node-content elopher-current-node))
+         (address (elopher-node-address elopher-current-node)))
+    (elopher-with-clean-buffer
+     (insert "LOADING RAW SERVER RESPONSE..."))
+    (if address
+        (elopher-get-selector address
+                              (lambda (proc event)
+                                (unless (string-prefix-p "deleted" event)
+                                  (elopher-with-clean-buffer
+                                   (insert elopher-selector-string))
+                                  (goto-char (point-min)))))
+      (progn
+        (elopher-with-clean-buffer
+         (insert elopher-start-index))
+        (goto-char (point-min)))))
+  (message "Displaying raw server response.  Reload or redraw to return to standard view."))
+ 
+;; File export retrieval
+
+(defvar elopher-download-filename)
+
+(defun elopher-get-node-download ()
+  "Getter which retrieves the current node and writes the result to a file."
+  (let* ((address (elopher-node-address elopher-current-node))
+         (selector (elopher-address-selector address)))
+    (elopher-visit-parent-node) ; Do first in case of non-local exits.
+    (let* ((filename-proposal (file-name-nondirectory selector))
+           (filename (read-file-name "Save file as: "
+                                     nil nil nil
+                                     (if (> (length filename-proposal) 0)
+                                         filename-proposal
+                                       "gopher.file"))))
+      (message "Downloading...")
+      (setq elopher-download-filename filename)
+      (elopher-get-selector address
+                            (lambda (proc event)
+                              (let ((coding-system-for-write 'binary))
+                                (with-temp-file elopher-download-filename
+                                  (insert elopher-selector-string)
+                                  (message (format "Download complate, saved to file %s."
+                                                   elopher-download-filename)))))))))
+
+
+;;; Navigation procedures
 ;;
 
 (defun elopher-next-link ()
+  "Move point to the next link on the current page."
   (interactive)
   (forward-button 1))
 
 (defun elopher-prev-link ()
+  "Move point to the previous link on the current page."
   (interactive)
   (backward-button 1))
 
 (defun elopher-click-link (button)
-  (apply (button-get button 'link-getter) (button-get button 'link-address))
-  (setq elopher-current-place (list link-getter link-address)))
-
-(defun elopher-follow-closest-link ()
+  "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
+  (let ((node (button-get button 'elopher-node)))
+    (elopher-visit-node node)))
+
+(defun elopher-click-url (button)
+  "Function called when the url link BUTTON is activated (via mouse or keypress)."
+  (let ((url (button-get button 'elopher-url)))
+    (if elopher-open-urls-with-eww
+        (browse-web url)
+      (browse-url url))))
+
+(defun elopher-follow-current-link ()
+  "Open the link or url at point."
   (interactive)
   (push-button))
 
 (defun elopher-go ()
   "Go to a particular gopher site."
   (interactive)
-  (let* ((selector "")
-         (hostname (read-from-minibuffer "Gopher host: "))
-         (port 70)
+  (let* (
+         (hostname (read-string "Gopher host: "))
+         (selector (read-string "Selector (default none): " nil nil ""))
+         (port (read-string "Port (default 70): " nil nil 70))
          (address (list selector hostname port)))
-    (elopher-get-index "" (read-from-minibuffer "Gopher host: ") 70)i
-    (setq elopher-current-place (list #'elopher-get-index address))))
+    (elopher-visit-node
+     (elopher-make-node elopher-current-node
+                        address
+                        #'elopher-get-index-node))))
+
+(defun  elopher-redraw ()
+  "Redraw current page."
+  (interactive)
+  (elopher-visit-node elopher-current-node))
 
 (defun  elopher-reload ()
   "Reload current page."
   (interactive)
-  (if elopher-current-place
-      (let ((link-getter (car elopher-current-place))
-            (address (cadr elopher-current-place)))
-        (apply link-getter address))
-    (elopher-get-start-page)))
+  (elopher-reload-current-node))
+
+(defun elopher-view-raw ()
+  "View current page as plain text."
+  (interactive)
+  (elopher-visit-node elopher-current-node
+                      #'elopher-get-node-raw))
+
+(defun elopher-back ()
+  "Go to previous site."
+  (interactive)
+  (if (elopher-node-parent elopher-current-node)
+      (elopher-visit-parent-node)
+    (message "No previous site.")))
+
+(defun elopher-download ()
+  "Download the link at point."
+  (interactive)
+  (let ((button (button-at (point))))
+    (if button
+        (let ((node (button-get button 'elopher-node)))
+          (if node
+              (elopher-visit-node (button-get button 'elopher-node)
+                                  #'elopher-get-node-download)
+            (message "Can only download gopher links, not general URLs.")))
+      (message "No link selected."))))
+
+;;; Mode and keymap
+;;
+
+(defvar elopher-mode-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map (kbd "TAB") 'elopher-next-link)
+    (define-key map (kbd "<backtab>") 'elopher-prev-link)
+    (define-key map (kbd "u") 'elopher-back)
+    (define-key map (kbd "g") 'elopher-go)
+    (define-key map (kbd "r") 'elopher-redraw)
+    (define-key map (kbd "R") 'elopher-reload)
+    (define-key map (kbd "w") 'elopher-view-raw)
+    (define-key map (kbd "d") 'elopher-download)
+    (when (fboundp 'evil-define-key)
+      (evil-define-key 'normal map
+        (kbd "TAB") 'elopher-next-link
+        (kbd "C-]") 'elopher-follow-current-link
+        (kbd "C-t") 'elopher-back
+        (kbd "u") 'elopher-back
+        (kbd "g") 'elopher-go
+        (kbd "r") 'elopher-redraw
+        (kbd "R") 'elopher-reload
+        (kbd "w") 'elopher-view-raw
+        (kbd "d") 'elopher-download))
+    map)
+  "Keymap for gopher client.")
+
+(define-derived-mode elopher-mode special-mode "elopher"
+  "Major mode for elopher, an elisp gopher client.")
+
 
 ;;; Main start procedure
 ;;
@@ -314,12 +638,9 @@
 (defun elopher ()
   "Start elopher with default landing page."
   (interactive)
-  (switch-to-buffer "*elopher*")
-  (elopher-mode)
-  (setq elopher-history nil)
-  (setq elopher-place-history nil)
-  (setq elopher-current-place nil)
-  (elopher-get-start-page))
-
+  (setq elopher-current-node nil)
+  (let ((start-node (elopher-make-node nil nil #'elopher-get-index-node)))
+    (elopher-visit-node start-node))
+  "Started Elopher.") ; Otherwise (elopher) evaluates to start page string.
 
 ;;; elopher.el ends here