Luke Gorrie's (luke@bluetail.com) patches for implementing C-p and C-…

…n in

Goatee.

Goatee/buffer.lisp

@@ -85,6 +85,18 @@
   (dbl-insert-after (make-buffer-line obj :tick (incf (tick obj))) (lines
 								    obj)))
 
+(defgeneric first-line-p (line)
+  (:documentation "Returns true if line is the first line in a buffer"))
+
+(defmethod first-line-p ((line buffer-line))
+  (not (typep (prev line) 'buffer-line)))
+
+(defgeneric last-line-p (line)
+  (:documentation "Returns true if line is the last line in a buffer"))
+
+(defmethod last-line-p ((line buffer-line))
+  (null (next line)))
+
 (defgeneric char-ref (buffer position))
 
 (defmethod char-ref ((buf basic-buffer) position)

Goatee/editable-area.lisp

@@ -22,7 +22,11 @@
 		  :documentation "buffer pointer to line in buffer
   that's at the bottom of the area.  The bp is not necessarily at the
   beginning of the line.")
-   (last-line :accessor last-line :initarg :last-line :initform nil))
+   (last-line :accessor last-line :initarg :last-line :initform nil)
+   (last-command :accessor last-command :initform nil)
+   (goal-column :accessor goal-column :initform nil
+		:documentation "Goal column for next-line command when
+  moving over a short line"))
   (:documentation "An abstract superclass for the on-screen area
   devoted to Goatee editing.  Roughly equivalent to a window in GNU Emacs."))
 

Goatee/editable-buffer.lisp

@@ -242,6 +242,25 @@
 (defmethod end-of-buffer* ((buf editable-buffer))
   (location* (buffer-end buf)))
 
+(defgeneric next-line (buffer &optional n &key position line pos)
+  (:documentation "Return the line N places from LINE, and a POS in it.
+If LINE is not given, uses the BUFFER's current line.
+If N is negative, goes backwards.
+POS is the position in the line to return as the second value (trimmed
+if beyond the actual line's maximum)."))
+
+(defmethod next-line ((buf editable-buffer) &optional (n 1)
+		      &key (position (point buf)) line (pos 0))
+  (let ((line (or line (location* position)))
+	(forward (> n 0))
+	(times (abs n)))
+    (loop for i upto times
+	  for cur-line = line then (if forward (next line) (prev line))
+	  when (or (not (typep cur-line 'buffer-line)) (null cur-line))
+	    do (error 'buffer-bounds-error :buffer buf :line line)
+	  finally
+	  (return (values cur-line (min pos (line-last-point cur-line)))))))
+
 ;;; These iteration constructs need a bit more thought.
 ;;; map-over-region in its current state may not do the right thing if
 ;;; the buffer is modified in the region, but what is the right thing?

Goatee/goatee-command.lisp

@@ -79,7 +79,8 @@
 					       (print c *debug-io*)
 					       (beep)
 					       (return-from error-out nil)))))
-	      (funcall command :input-gesture gesture)))
+	      (funcall command :input-gesture gesture)
+	      (setf (last-command area) command)))
 	  (redisplay-area area)))))
 
 (defun insert-character (&key input-gesture &allow-other-keys)
@@ -119,6 +120,24 @@
 	  (delete-char *buffer*)
 	  (delete-char *buffer* (- last-point pos))))))
 
+;; Line motion
+
+(defun up-line (&key &allow-other-keys)
+  (move-lines -1))
+
+(defun down-line (&key &allow-other-keys)
+  (move-lines 1))
+
+(defun move-lines (n)
+  (unless (goal-column-preserving-p (last-command *area*))
+    (setf (goal-column *area*) (pos (point *buffer*))))
+  (setf (point* *buffer*)
+	(next-line *buffer* n :pos (goal-column *area*))))
+
+(defun goal-column-preserving-p (cmd)
+  (member cmd '(up-line down-line)))
+
+
 (loop for i from (char-code #\space) to (char-code #\~)
       do (add-gesture-command-to-table (code-char i)
 				       'insert-character
@@ -163,6 +182,15 @@
 (add-gesture-command-to-table '(#\u :control)
 			      'clear-input-buffer
 			      *simple-area-gesture-table*)
+
+(add-gesture-command-to-table '(#\p :control)
+			      'up-line
+			      *simple-area-gesture-table*)
+
+(add-gesture-command-to-table '(#\n :control)
+			      'down-line
+			      *simple-area-gesture-table*)
+
 ;;; Debugging fun
 
 (defun goatee-break (&key &allow-other-keys)