From 6aef0678f12c31e43d1584cf0b32bfcffc7156c0 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 18:45:01 +0200
Subject: [PATCH 01/14] Refactor ein:notebook-execute-current-cell

---
 ein-cell.el                | 15 ++++++-----
 tests/test-ein-notebook.el | 53 +++++++++++++++++++++-----------------
 2 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/ein-cell.el b/ein-cell.el
index 78f14a2..7de64d5 100644
--- a/ein-cell.el
+++ b/ein-cell.el
@@ -780,13 +780,14 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
   (ein:cell-set-input-prompt cell "*")
   (ein:cell-running-set cell t)
   (oset cell :dynamic t)
-  (let* ((callbacks
-          (list
-           :execute_reply  (cons #'ein:cell--handle-execute-reply  cell)
-           :output         (cons #'ein:cell--handle-output         cell)
-           :clear_output   (cons #'ein:cell--handle-clear-output   cell)
-           :set_next_input (cons #'ein:cell--handle-set-next-input cell))))
-    (apply #'ein:kernel-execute kernel code callbacks args)))
+  (apply #'ein:kernel-execute kernel code (ein:cell-make-callbacks cell) args))
+
+(defmethod ein:cell-make-callbacks ((cell ein:codecell))
+  (list
+   :execute_reply  (cons #'ein:cell--handle-execute-reply  cell)
+   :output         (cons #'ein:cell--handle-output         cell)
+   :clear_output   (cons #'ein:cell--handle-clear-output   cell)
+   :set_next_input (cons #'ein:cell--handle-set-next-input cell)))
 
 (defmethod ein:cell--handle-execute-reply ((cell ein:codecell) content)
   (ein:cell-set-input-prompt cell (plist-get content :execution_count))
diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 882af6c..4a3f029 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -70,6 +70,27 @@
 (defun eintest:notebook-enable-mode (buffer)
   (with-current-buffer buffer (ein:notebook-plain-mode) buffer))
 
+(defun eintest:kernel-fake-execute-reply (kernel msg-id execution-count)
+  (let* ((payload nil)
+         (content (list :execution_count 1 :payload payload))
+         (packet (list :header (list :msg_type "execute_reply")
+                       :parent_header (list :msg_id msg-id)
+                       :content content)))
+    (ein:kernel--handle-shell-reply kernel (json-encode packet))))
+
+(defun eintest:kernel-fake-stream (kernel msg-id data)
+  (let* ((content (list :data data
+                        :name "stdout"))
+         (packet (list :header (list :msg_type "stream")
+                       :parent_header (list :msg_id msg-id)
+                       :content content)))
+    (ein:kernel--handle-iopub-reply kernel (json-encode packet))))
+
+(defun eintest:search-forward-from (string start)
+  (save-excursion
+    (goto-char start)
+    (search-forward string nil t)))
+
 
 ;; from-json
 
@@ -332,15 +353,11 @@ some text
            (cell (ein:notebook-get-current-cell))
            (kernel (ein:$notebook-kernel ein:notebook))
            (msg-id "DUMMY-MSG-ID")
-           (callbacks
-            (list
-             :execute_reply  (cons #'ein:cell--handle-execute-reply  cell)
-             :output         (cons #'ein:cell--handle-output         cell)
-             :clear_output   (cons #'ein:cell--handle-clear-output   cell)
-             :set_next_input (cons #'ein:cell--handle-set-next-input cell))))
+           (callbacks (ein:cell-make-callbacks cell)))
       (should (ein:$kernel-p kernel))
       (should (ein:codecell-p cell))
       (should (ein:$kernel-p (oref cell :kernel)))
+      ;; Execute
       (insert text)
       (mocker-let ((ein:kernel-execute
                     (kernel code callbacks kwd-silent silent)
@@ -350,25 +367,13 @@ some text
                     ((:input (list kernel) :output t))))
         (ein:notebook-execute-current-cell))
       (ein:kernel-set-callbacks-for-msg kernel msg-id callbacks)
-      (save-excursion
-        (goto-char (point-min))
-        (should-not (search-forward "In [1]:" nil t)))
-      (let* ((payload nil)
-             (content (list :execution_count 1 :payload payload))
-             (packet (list :header (list :msg_type "execute_reply")
-                           :parent_header (list :msg_id msg-id)
-                           :content content)))
-        (ein:kernel--handle-shell-reply kernel (json-encode packet)))
+      ;; Execute reply
+      (should-not (eintest:search-forward-from "In [1]:" (point-min)))
+      (eintest:kernel-fake-execute-reply kernel msg-id 1)
       (should (= (oref cell :input-prompt-number) 1))
-      (save-excursion
-        (goto-char (point-min))
-        (should (search-forward "In [1]:" nil t)))
-      (let* ((content (list :data "'Hello World'"
-                            :name "stdout"))
-             (packet (list :header (list :msg_type "stream")
-                           :parent_header (list :msg_id msg-id)
-                           :content content)))
-        (ein:kernel--handle-iopub-reply kernel (json-encode packet)))
+      (should (eintest:search-forward-from "In [1]:" (point-min)))
+      ;; Stream output
+      (eintest:kernel-fake-stream kernel msg-id "'Hello World'")
       (should (= (ein:cell-num-outputs cell) 1))
       (save-excursion
         (goto-char (point-min))

From 74a433dd7b108a778aad9e6817fbcf4341f9c0f3 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 18:51:56 +0200
Subject: [PATCH 02/14] Refactor ein:notebook-execute-current-cell more

---
 tests/test-ein-notebook.el | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 4a3f029..088ae6b 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -346,6 +346,16 @@ some text
 
 ;; Kernel related things
 
+(defun eintest:notebook-fake-execution (kernel text msg-id callbacks)
+  (mocker-let ((ein:kernel-execute
+                (kernel code callbacks kwd-silent silent)
+                ((:input (list kernel text callbacks :silent nil))))
+               (ein:kernel-ready-p
+                (kernel)
+                ((:input (list kernel) :output t))))
+    (ein:notebook-execute-current-cell))
+  (ein:kernel-set-callbacks-for-msg kernel msg-id callbacks))
+
 (ert-deftest ein:notebook-execute-current-cell ()
   (with-current-buffer (eintest:notebook-make-empty)
     (ein:notebook-insert-cell-below-command)
@@ -359,14 +369,7 @@ some text
       (should (ein:$kernel-p (oref cell :kernel)))
       ;; Execute
       (insert text)
-      (mocker-let ((ein:kernel-execute
-                    (kernel code callbacks kwd-silent silent)
-                    ((:input (list kernel text callbacks :silent nil))))
-                   (ein:kernel-ready-p
-                    (kernel)
-                    ((:input (list kernel) :output t))))
-        (ein:notebook-execute-current-cell))
-      (ein:kernel-set-callbacks-for-msg kernel msg-id callbacks)
+      (eintest:notebook-fake-execution kernel text msg-id callbacks)
       ;; Execute reply
       (should-not (eintest:search-forward-from "In [1]:" (point-min)))
       (eintest:kernel-fake-execute-reply kernel msg-id 1)

From c0839fa79515823a1bbef76f3a4b035d3973a497 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 18:58:27 +0200
Subject: [PATCH 03/14] Refactor ein:notebook-execute-current-cell more (2)

---
 tests/test-ein-notebook.el | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 088ae6b..4bdd446 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -346,6 +346,11 @@ some text
 
 ;; Kernel related things
 
+(defun eintest:notebook-check-kernel-and-codecell (kernel cell)
+  (should (ein:$kernel-p kernel))
+  (should (ein:codecell-p cell))
+  (should (ein:$kernel-p (oref cell :kernel))))
+
 (defun eintest:notebook-fake-execution (kernel text msg-id callbacks)
   (mocker-let ((ein:kernel-execute
                 (kernel code callbacks kwd-silent silent)
@@ -364,9 +369,7 @@ some text
            (kernel (ein:$notebook-kernel ein:notebook))
            (msg-id "DUMMY-MSG-ID")
            (callbacks (ein:cell-make-callbacks cell)))
-      (should (ein:$kernel-p kernel))
-      (should (ein:codecell-p cell))
-      (should (ein:$kernel-p (oref cell :kernel)))
+      (eintest:notebook-check-kernel-and-codecell kernel cell)
       ;; Execute
       (insert text)
       (eintest:notebook-fake-execution kernel text msg-id callbacks)

From 35c3e9bd7b26fa9a8cf0e95f964c4ef55988a660 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 19:00:44 +0200
Subject: [PATCH 04/14] Fix ein:notebook-execute-current-cell

"Hellow World" for eintest:kernel-fake-stream had unnecessary single
quotes.
---
 tests/test-ein-notebook.el | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 4bdd446..05fde5d 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -379,13 +379,13 @@ some text
       (should (= (oref cell :input-prompt-number) 1))
       (should (eintest:search-forward-from "In [1]:" (point-min)))
       ;; Stream output
-      (eintest:kernel-fake-stream kernel msg-id "'Hello World'")
+      (eintest:kernel-fake-stream kernel msg-id "Hello World")
       (should (= (ein:cell-num-outputs cell) 1))
       (save-excursion
         (goto-char (point-min))
         (should (search-forward "In [1]:" nil t))
         (should (search-forward "print 'Hello World'" nil t))
-        (should (search-forward "Hello World" nil t)) ; stream output
+        (should (search-forward "\nHello World\n" nil t)) ; stream output
         (should-not (search-forward "Hello World" nil t))))))
 
 

From 1127de66a710f722d385089041d26cc23195f50c Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 20:11:51 +0200
Subject: [PATCH 05/14] Add two tests for undo in notebook

---
 tests/test-ein-notebook.el | 77 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 05fde5d..5f3da2e 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -388,6 +388,83 @@ some text
         (should (search-forward "\nHello World\n" nil t)) ; stream output
         (should-not (search-forward "Hello World" nil t))))))
 
+
+;; Notebook undo
+
+(ert-deftest ein:notebook-undo-after-execution ()
+  (with-current-buffer (eintest:notebook-make-empty)
+    (ein:notebook-insert-cell-below-command)
+    (let* ((text "print 'Hello World'")
+           (output-text "Hello World\n")
+           (cell (ein:notebook-get-current-cell))
+           (kernel (ein:$notebook-kernel ein:notebook))
+           (msg-id "DUMMY-MSG-ID")
+           (callbacks (ein:cell-make-callbacks cell))
+           (check-output
+            (lambda ()
+              (save-excursion
+                (goto-char (point-min))
+                (should (search-forward (concat "\n" output-text) nil t))
+                (should-not (search-forward "Hello World" nil t))))))
+      (eintest:notebook-check-kernel-and-codecell kernel cell)
+      ;; Execute
+      (insert text)
+      (undo-boundary)
+      (eintest:notebook-fake-execution kernel text msg-id callbacks)
+      (ein:kernel-set-callbacks-for-msg kernel msg-id callbacks)
+      ;; Stream output
+      (eintest:kernel-fake-stream kernel msg-id output-text)
+      (funcall check-output)
+      ;; Undo
+      (should (equal (ein:cell-get-text cell) text))
+      (undo)
+      (should (equal (ein:cell-get-text cell) ""))
+      ;; FIXME: Known bug. (it must succeed.)
+      (should-error (funcall check-output)))))
+
+(ert-deftest ein:notebook-undo-after-execution-2-cells ()
+  (with-current-buffer (eintest:notebook-make-empty)
+    (ein:notebook-insert-cell-below-command)
+    (ein:notebook-insert-cell-above-command)
+    (let* ((text "print 'Hello World\\n' * 10")
+           (next-text "something")
+           (output-text
+            (apply #'concat (loop repeat 10 collect "Hello World\n")))
+           (cell (ein:notebook-get-current-cell))
+           (next-cell (ein:cell-next cell))
+           (kernel (ein:$notebook-kernel ein:notebook))
+           (msg-id "DUMMY-MSG-ID")
+           (callbacks (ein:cell-make-callbacks cell))
+           (check-output
+            (lambda ()
+              (save-excursion
+                (goto-char (point-min))
+                (should (search-forward (concat "\n" output-text) nil t))
+                (should-not (search-forward "Hello World" nil t))))))
+      (eintest:notebook-check-kernel-and-codecell kernel cell)
+      ;; Execute
+      (insert text)
+      (undo-boundary)
+      (let ((pos (point)))
+        ;; Do not use `save-excursion' because it does not record undo.
+        (ein:notebook-goto-next-input-command)
+        (insert next-text)
+        (undo-boundary)
+        (goto-char pos))
+      (eintest:notebook-fake-execution kernel text msg-id callbacks)
+      (ein:kernel-set-callbacks-for-msg kernel msg-id callbacks)
+      ;; Stream output
+      (eintest:kernel-fake-stream kernel msg-id output-text)
+      (funcall check-output)
+      ;; Undo
+      (should (equal (ein:cell-get-text cell) text))
+      (should (equal (ein:cell-get-text next-cell) next-text))
+      (undo)
+      (should (equal (ein:cell-get-text cell) text))
+      ;; FIXME: Known bug. (these two must succeed.)
+      (should-error (should (equal (ein:cell-get-text next-cell) "")))
+      (should-error (funcall check-output)))))
+
 
 ;; Notebook mode
 

From 4f3695c4cf184f13e3ddb7c360072b05a4789995 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 20:41:27 +0200
Subject: [PATCH 06/14] Refactor ein:notebook-undo-after-execution*

.. and ein:notebook-execute-current-cell.
---
 tests/test-ein-notebook.el | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 5f3da2e..5cbada4 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -86,10 +86,16 @@
                        :content content)))
     (ein:kernel--handle-iopub-reply kernel (json-encode packet))))
 
-(defun eintest:search-forward-from (string start)
+(defun eintest:check-search-forward-from (start string &optional null-string)
+  "Search STRING from START and check it is found.
+When non-`nil' NULL-STRING is given, it is searched from the
+position where the search of the STRING ends and check that it
+is not found."
   (save-excursion
     (goto-char start)
-    (search-forward string nil t)))
+    (should (search-forward string nil t))
+    (when null-string
+      (should-not (search-forward null-string nil t)))))
 
 
 ;; from-json
@@ -374,10 +380,10 @@ some text
       (insert text)
       (eintest:notebook-fake-execution kernel text msg-id callbacks)
       ;; Execute reply
-      (should-not (eintest:search-forward-from "In [1]:" (point-min)))
+      (should-error (eintest:check-search-forward-from (point-min) "In [1]:"))
       (eintest:kernel-fake-execute-reply kernel msg-id 1)
       (should (= (oref cell :input-prompt-number) 1))
-      (should (eintest:search-forward-from "In [1]:" (point-min)))
+      (eintest:check-search-forward-from (point-min) "In [1]:")
       ;; Stream output
       (eintest:kernel-fake-stream kernel msg-id "Hello World")
       (should (= (ein:cell-num-outputs cell) 1))
@@ -402,10 +408,8 @@ some text
            (callbacks (ein:cell-make-callbacks cell))
            (check-output
             (lambda ()
-              (save-excursion
-                (goto-char (point-min))
-                (should (search-forward (concat "\n" output-text) nil t))
-                (should-not (search-forward "Hello World" nil t))))))
+              (eintest:check-search-forward-from
+               (point-min) (concat "\n" output-text) "Hello World"))))
       (eintest:notebook-check-kernel-and-codecell kernel cell)
       ;; Execute
       (insert text)
@@ -437,10 +441,8 @@ some text
            (callbacks (ein:cell-make-callbacks cell))
            (check-output
             (lambda ()
-              (save-excursion
-                (goto-char (point-min))
-                (should (search-forward (concat "\n" output-text) nil t))
-                (should-not (search-forward "Hello World" nil t))))))
+              (eintest:check-search-forward-from
+               (point-min) (concat "\n" output-text) "Hello World"))))
       (eintest:notebook-check-kernel-and-codecell kernel cell)
       ;; Execute
       (insert text)

From 7bf8acd484c65e6b6def1cdcf2fdc9a0e937c0e1 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 20:42:14 +0200
Subject: [PATCH 07/14] Rename to ein:notebook-undo-after-execution-1-cell

---
 tests/test-ein-notebook.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 5cbada4..43658ce 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -397,7 +397,7 @@ some text
 
 ;; Notebook undo
 
-(ert-deftest ein:notebook-undo-after-execution ()
+(ert-deftest ein:notebook-undo-after-execution-1-cell ()
   (with-current-buffer (eintest:notebook-make-empty)
     (ein:notebook-insert-cell-below-command)
     (let* ((text "print 'Hello World'")

From 5b06f8fcd8f37692ec8fd9b090ae7ebbebb5b5d6 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 21:04:47 +0200
Subject: [PATCH 08/14] More precise check in undo tests

---
 ein-cell.el                |  4 +++-
 tests/test-ein-notebook.el | 11 +++++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/ein-cell.el b/ein-cell.el
index 7de64d5..7d006a3 100644
--- a/ein-cell.el
+++ b/ein-cell.el
@@ -543,7 +543,9 @@ Called from ewoc pretty printer via `ein:cell-pp'."
 
 (defmethod ein:cell-location ((cell ein:basecell) &optional elm end)
   "Return the starting location of CELL.
-ELM is a name (keyword) of element in the `:element-names' slot of CELL.
+ELM is a name (keyword) of element that `ein:cell-element-get'
+understands.  Note that you can't use `:output' since it returns
+a list.  Use `:after-input' instead.
 If END is non-`nil', return the location of next element."
   (unless elm (setq elm :prompt))
   (let ((element (oref cell :element)))
diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 43658ce..9f02737 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -97,6 +97,11 @@ is not found."
     (when null-string
       (should-not (search-forward null-string nil t)))))
 
+(defun eintest:cell-check-output (cell regexp)
+  (save-excursion
+    (goto-char (ein:cell-location cell :after-input))
+    (should (looking-at-p (concat "\\=" regexp "\n")))))
+
 
 ;; from-json
 
@@ -408,8 +413,7 @@ some text
            (callbacks (ein:cell-make-callbacks cell))
            (check-output
             (lambda ()
-              (eintest:check-search-forward-from
-               (point-min) (concat "\n" output-text) "Hello World"))))
+              (eintest:cell-check-output cell output-text))))
       (eintest:notebook-check-kernel-and-codecell kernel cell)
       ;; Execute
       (insert text)
@@ -441,8 +445,7 @@ some text
            (callbacks (ein:cell-make-callbacks cell))
            (check-output
             (lambda ()
-              (eintest:check-search-forward-from
-               (point-min) (concat "\n" output-text) "Hello World"))))
+              (eintest:cell-check-output cell output-text))))
       (eintest:notebook-check-kernel-and-codecell kernel cell)
       ;; Execute
       (insert text)

From 311151fdc83984c1c02099908f497a34ee430253 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 21:05:22 +0200
Subject: [PATCH 09/14] Inhibit undo in pretty printer

---
 ein-notebook.el | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/ein-notebook.el b/ein-notebook.el
index e1b46a8..1192abb 100644
--- a/ein-notebook.el
+++ b/ein-notebook.el
@@ -306,7 +306,14 @@ See `ein:notebook-open' for more information."
 
 (defun ein:notebook-pp (ewoc-data)
   (let ((path (ein:$node-path ewoc-data))
-        (data (ein:$node-data ewoc-data)))
+        (data (ein:$node-data ewoc-data))
+        (inhibit-read-only t)
+        (buffer-undo-list t))         ; disable undo recording
+    ;; FIXME: Having `inhibit-read-only' and `buffer-undo-list' should
+    ;;        make some of the same statements in ein-notebook/cell.el
+    ;;        removable.  These must be removed after careful review
+    ;;        and maybe adding more tests.  I will just let them be
+    ;;        there since it is harmless.
     (case (car path)
       (cell (ein:cell-pp (cdr path) data)))))
 

From 363b63de04d414cfcd3f3a520b4b1735a66d6443 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 21:35:16 +0200
Subject: [PATCH 10/14] Make undo in notebook configurable

Note that ein:notebook-empty-undo-maybe is called in:
* ein:notebook-pp
* ein:notebook-delete-cell
---
 ein-notebook.el | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/ein-notebook.el b/ein-notebook.el
index 1192abb..cae5b6d 100644
--- a/ein-notebook.el
+++ b/ein-notebook.el
@@ -54,6 +54,34 @@
 
 ;;; Configuration
 
+(defcustom ein:notebook-enable-undo 'yes
+  "Configure undo in notebook buffers.
+
+`no' : symbol
+    Do not use undo in notebook buffers.  It is the safest option.
+`yes' : symbol
+    Enable undo in notebook buffers.  You can't undo after
+    modification of cell (execution, add, remove, etc.).  This
+    is default.
+`full' : symbol
+    Enable full undo in notebook buffers.  It is powerful but
+    sometime (typically after the cell specific commands) undo
+    mess up notebook buffer.  Use it on your own risk.  When the
+    buffer is messed up, you can just redo and continue editing,
+    or save it once and reopen it if you want to be careful.
+
+You need to reopen the notebook buffer to reflect the change of
+this value."
+  :type '(choice (const :tag "No" no)
+                 (const :tag "Yes" yes)
+                 (const :tag "Full" full))
+  :group 'ein)
+
+(defun ein:notebook-empty-undo-maybe ()
+  "Empty `buffer-undo-list' if `ein:notebook-enable-undo' is `yes'."
+  (when (eq ein:notebook-enable-undo 'yes)
+    (setq buffer-undo-list nil)))
+
 (defcustom ein:notebook-discard-output-on-save 'no
   "Configure if the output part of the cell should be saved or not.
 
@@ -295,6 +323,8 @@ See `ein:notebook-open' for more information."
   (assert ein:notebook)  ; make sure in a notebook buffer
   (ein:notebook-from-json ein:notebook (ein:$notebook-data ein:notebook))
   (setq buffer-undo-list nil)  ; clear undo history
+  (when (eq ein:notebook-enable-undo 'no)
+    (setq buffer-undo-list t))
   (ein:notebook-mode)
   (setf (ein:$notebook-notification ein:notebook)
         (ein:notification-setup (current-buffer)))
@@ -315,7 +345,8 @@ See `ein:notebook-open' for more information."
     ;;        and maybe adding more tests.  I will just let them be
     ;;        there since it is harmless.
     (case (car path)
-      (cell (ein:cell-pp (cdr path) data)))))
+      (cell (ein:cell-pp (cdr path) data))))
+  (ein:notebook-empty-undo-maybe))
 
 
 ;;; Initialization.
@@ -392,7 +423,8 @@ See `ein:notebook-open' for more information."
     (apply #'ewoc-delete
            (ein:$notebook-ewoc notebook)
            (ein:cell-all-element cell)))
-  (setf (ein:$notebook-dirty notebook) t))
+  (setf (ein:$notebook-dirty notebook) t)
+  (ein:notebook-empty-undo-maybe))
 
 (defun ein:notebook-delete-cell-command ()
   "Delete a cell.  \(WARNING: no undo!)

From 0c13bc4234bc6c77b10ea379f97f5f31eea8d60b Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 22:14:20 +0200
Subject: [PATCH 11/14] Modifying undo in PP is wrong

Previous change was not complete since the test does NOT fail.
The test must fail because the test was for `full' undo but
actually it was tested against normal undo.

It turned out let binding of buffer-undo-list in ein-cell.el
was the right way to do it, since EWOC does some buffer
modification outside of the pretty printer.  Therefore, setting
inhibit-read-only and buffer-undo-list in the pretty printer
makes no sense.  Thus, they are removed from ein:notebook-pp.

This means that wrapping EWOC functions with let binding of
buffer-undo-list is essential.  Meaning that what I wrote in
the FIXME ein:notebook-pp was wrong.  Therefore,
ein:notebook-empty-undo-maybe cannot be called in ein:notebook-pp
and ein:notebook-empty-undo-maybe must be called in every single
functions that modifies buffer via EWOC.

Tests for three cases of undo configuration are added.
These test still fail:
ein:notebook-undo-after-execution-1-cell/yes
ein:notebook-undo-after-execution-2-cells/yes
---
 ein-notebook.el            | 26 +++++++++----------
 tests/test-ein-notebook.el | 52 ++++++++++++++++++++++++++++++--------
 2 files changed, 54 insertions(+), 24 deletions(-)

diff --git a/ein-notebook.el b/ein-notebook.el
index cae5b6d..4f3823d 100644
--- a/ein-notebook.el
+++ b/ein-notebook.el
@@ -336,17 +336,9 @@ See `ein:notebook-open' for more information."
 
 (defun ein:notebook-pp (ewoc-data)
   (let ((path (ein:$node-path ewoc-data))
-        (data (ein:$node-data ewoc-data))
-        (inhibit-read-only t)
-        (buffer-undo-list t))         ; disable undo recording
-    ;; FIXME: Having `inhibit-read-only' and `buffer-undo-list' should
-    ;;        make some of the same statements in ein-notebook/cell.el
-    ;;        removable.  These must be removed after careful review
-    ;;        and maybe adding more tests.  I will just let them be
-    ;;        there since it is harmless.
+        (data (ein:$node-data ewoc-data)))
     (case (car path)
-      (cell (ein:cell-pp (cdr path) data))))
-  (ein:notebook-empty-undo-maybe))
+      (cell (ein:cell-pp (cdr path) data)))))
 
 
 ;;; Initialization.
@@ -514,6 +506,7 @@ Prefixes are act same as the normal `yank' command."
         (ein:cell-insert-below base-cell cell))
        (t (error (concat "`base-cell' is `nil' but ncells != 0.  "
                          "There is something wrong..."))))
+      (ein:notebook-empty-undo-maybe)
       (ein:cell-goto cell)
       (setf (ein:$notebook-dirty notebook) t))
     cell))
@@ -544,6 +537,7 @@ when the prefix argument is given."
             (ein:cell-enter-first cell))))
        (t (error (concat "`base-cell' is `nil' but ncells > 1.  "
                          "There is something wrong..."))))
+      (ein:notebook-empty-undo-maybe)
       (ein:cell-goto cell)
       (setf (ein:$notebook-dirty notebook) t))
     cell))
@@ -576,6 +570,7 @@ directly."
       (let ((new (ein:cell-convert-inplace cell type)))
         (when (ein:codecell-p new)
           (oset new :kernel (ein:$notebook-kernel ein:notebook)))
+        (ein:notebook-empty-undo-maybe)
         (ein:cell-goto new)))))
 
 (defun ein:notebook-change-cell-type ()
@@ -599,7 +594,8 @@ Prompt will appear in the minibuffer."
         (when (ein:codecell-p new)
           (oset new :kernel (ein:$notebook-kernel ein:notebook)))
         (when level
-          (ein:cell-change-level new type))))))
+          (ein:cell-change-level new type))
+        (ein:notebook-empty-undo-maybe)))))
 
 (defun ein:notebook-split-cell-at-point (&optional no-trim)
   "Split cell at current position. Newlines at the splitting
@@ -702,6 +698,7 @@ If prefix is given, merge current cell into previous cell."
 
 (defun ein:notebook-toggle-output (notebook cell)
   (ein:cell-toggle-output cell)
+  (ein:notebook-empty-undo-maybe)
   (setf (ein:$notebook-dirty notebook) t))
 
 (defun ein:notebook-toggle-output-command ()
@@ -715,6 +712,7 @@ This does not alter the actual data stored in the cell."
   (mapc (lambda (c)
           (when (ein:codecell-p c) (ein:cell-set-collapsed c collapsed)))
         (ein:notebook-get-cells notebook))
+  (ein:notebook-empty-undo-maybe)
   (setf (ein:$notebook-dirty notebook) t))
 
 (defun ein:notebook-set-collapsed-all-command (&optional show)
@@ -729,7 +727,8 @@ Do not clear input prompt when the prefix argument is given."
   (ein:notebook-with-cell #'ein:codecell-p
     (ein:cell-clear-output cell t t t)
     (unless preserve-input-prompt
-      (ein:cell-set-input-prompt cell))))
+      (ein:cell-set-input-prompt cell))
+    (ein:notebook-empty-undo-maybe)))
 
 (defun ein:notebook-clear-all-output-command (&optional preserve-input-prompt)
   "Clear output from all cells.
@@ -740,7 +739,8 @@ Do not clear input prompts when the prefix argument is given."
           do (when (ein:codecell-p cell)
                (ein:cell-clear-output cell t t t)
                (unless preserve-input-prompt
-                 (ein:cell-set-input-prompt cell))))
+                 (ein:cell-set-input-prompt cell))
+               (ein:notebook-empty-undo-maybe)))
     (ein:log 'error "Not in notebook buffer!")))
 
 
diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index 9f02737..a3885eb 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -402,7 +402,7 @@ some text
 
 ;; Notebook undo
 
-(ert-deftest ein:notebook-undo-after-execution-1-cell ()
+(defun eintest:notebook-undo-after-execution-1-cell ()
   (with-current-buffer (eintest:notebook-make-empty)
     (ein:notebook-insert-cell-below-command)
     (let* ((text "print 'Hello World'")
@@ -425,12 +425,15 @@ some text
       (funcall check-output)
       ;; Undo
       (should (equal (ein:cell-get-text cell) text))
-      (undo)
-      (should (equal (ein:cell-get-text cell) ""))
-      ;; FIXME: Known bug. (it must succeed.)
-      (should-error (funcall check-output)))))
+      (if (eq ein:notebook-enable-undo 'full)
+          (undo)
+        (should-error (undo)))
+      (when (eq ein:notebook-enable-undo 'full)
+        (should (equal (ein:cell-get-text cell) ""))
+        ;; FIXME: Known bug. (it must succeed.)
+        (should-error (funcall check-output))))))
 
-(ert-deftest ein:notebook-undo-after-execution-2-cells ()
+(defun eintest:notebook-undo-after-execution-2-cells ()
   (with-current-buffer (eintest:notebook-make-empty)
     (ein:notebook-insert-cell-below-command)
     (ein:notebook-insert-cell-above-command)
@@ -464,11 +467,38 @@ some text
       ;; Undo
       (should (equal (ein:cell-get-text cell) text))
       (should (equal (ein:cell-get-text next-cell) next-text))
-      (undo)
-      (should (equal (ein:cell-get-text cell) text))
-      ;; FIXME: Known bug. (these two must succeed.)
-      (should-error (should (equal (ein:cell-get-text next-cell) "")))
-      (should-error (funcall check-output)))))
+      (if (eq ein:notebook-enable-undo 'full)
+          (undo)
+        (should-error (undo)))
+      (when (eq ein:notebook-enable-undo 'full)
+        (should (equal (ein:cell-get-text cell) text))
+        ;; FIXME: Known bug. (these two must succeed.)
+        (should-error (should (equal (ein:cell-get-text next-cell) "")))
+        (should-error (funcall check-output))))))
+
+(ert-deftest ein:notebook-undo-after-execution-1-cell/no ()
+  (let ((ein:notebook-enable-undo 'no))
+    (eintest:notebook-undo-after-execution-1-cell)))
+
+(ert-deftest ein:notebook-undo-after-execution-1-cell/yes ()
+  (let ((ein:notebook-enable-undo 'yes))
+    (eintest:notebook-undo-after-execution-1-cell)))
+
+(ert-deftest ein:notebook-undo-after-execution-1-cell/full ()
+  (let ((ein:notebook-enable-undo 'full))
+    (eintest:notebook-undo-after-execution-1-cell)))
+
+(ert-deftest ein:notebook-undo-after-execution-2-cells/no ()
+  (let ((ein:notebook-enable-undo 'no))
+    (eintest:notebook-undo-after-execution-2-cells)))
+
+(ert-deftest ein:notebook-undo-after-execution-2-cells/yes ()
+  (let ((ein:notebook-enable-undo 'yes))
+    (eintest:notebook-undo-after-execution-2-cells)))
+
+(ert-deftest ein:notebook-undo-after-execution-2-cells/full ()
+  (let ((ein:notebook-enable-undo 'full))
+    (eintest:notebook-undo-after-execution-2-cells)))
 
 
 ;; Notebook mode

From 6b5b54c965dea22dcb36afe4a2bcc6dd12533a8b Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sat, 16 Jun 2012 23:33:58 +0200
Subject: [PATCH 12/14] Trigger ein:notebook-empty-undo-maybe via event

Previous tests were failed because undo was not reset after the
execution callbacks modified the buffer.  This is fixed by calling
ein:notebook-empty-undo-maybe via event in all the callbacks.
---
 ein-cell.el                | 16 ++++++++++------
 ein-events.el              |  4 +++-
 ein-notebook.el            |  4 ++++
 tests/test-ein-notebook.el |  3 +--
 4 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/ein-cell.el b/ein-cell.el
index 7d006a3..7321606 100644
--- a/ein-cell.el
+++ b/ein-cell.el
@@ -794,12 +794,15 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
 (defmethod ein:cell--handle-execute-reply ((cell ein:codecell) content)
   (ein:cell-set-input-prompt cell (plist-get content :execution_count))
   (ein:cell-running-set cell nil)
-  (ein:events-trigger
-   (oref cell :events) 'set_dirty.Notebook '(:value t)))
+  (let ((events (oref cell :events)))
+    (ein:events-trigger events 'set_dirty.Notebook '(:value t))
+    (ein:events-trigger events 'maybe_reset_undo.Notebook)))
 
 (defmethod ein:cell--handle-set-next-input ((cell ein:codecell) text)
-  (ein:events-trigger
-   (oref cell :events) 'set_next_input.Notebook (list :cell cell :text text)))
+  (let ((events (oref cell :events)))
+    (ein:events-trigger events 'set_next_input.Notebook
+                        (list :cell cell :text text))
+    (ein:events-trigger events 'maybe_reset_undo.Notebook)))
 
 
 
@@ -826,7 +829,7 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
        (plist-put json :traceback (plist-get content :traceback))))
     (ein:cell-append-output cell json t)
     ;; (oset cell :dirty t)
-    ))
+    (ein:events-trigger (oref cell :events) 'maybe_reset_undo.Notebook)))
 
 
 (defun ein:output-area-convert-mime-types (json data)
@@ -848,7 +851,8 @@ Called from ewoc pretty printer via `ein:cell-insert-output'."
   (ein:cell-clear-output cell
                          (plist-get content :stdout)
                          (plist-get content :stderr)
-                         (plist-get content :other)))
+                         (plist-get content :other))
+  (ein:events-trigger (oref cell :events) 'maybe_reset_undo.Notebook))
 
 
 ;;; Misc.
diff --git a/ein-events.el b/ein-events.el
index 1db3bc6..8c7aa70 100644
--- a/ein-events.el
+++ b/ein-events.el
@@ -62,7 +62,9 @@
 When EVENT-TYPE is triggered on the event handler EVENTS,
 CALLBACK is called.  CALLBACK must take two arguments:
 ARG as the first argument and DATA, which is passed via
-`ein:events-trigger', as the second."
+`ein:events-trigger', as the second.  When calling the function,
+current buffer is set to the configured buffer.  `ein:events-new'
+is used to configure the buffer."
   (assert (symbolp event-type))
   (let* ((table (oref events :callbacks))
          (cbs (gethash event-type table)))
diff --git a/ein-notebook.el b/ein-notebook.el
index 4f3823d..faa0249 100644
--- a/ein-notebook.el
+++ b/ein-notebook.el
@@ -356,6 +356,10 @@ See `ein:notebook-open' for more information."
                    (setf (ein:$notebook-dirty notebook)
                          (plist-get data :value)))
                  notebook)
+  (ein:events-on events
+                 'maybe_reset_undo.Notebook
+                 (lambda (&rest -ignore-)
+                   (ein:notebook-empty-undo-maybe)))
   ;; Bind events for sub components:
   (mapc (lambda (cell) (oset cell :events (ein:$notebook-events notebook)))
         (ein:notebook-get-cells notebook))
diff --git a/tests/test-ein-notebook.el b/tests/test-ein-notebook.el
index a3885eb..5ddc575 100644
--- a/tests/test-ein-notebook.el
+++ b/tests/test-ein-notebook.el
@@ -49,8 +49,7 @@
     (with-current-buffer (ein:notebook-request-open-callback
                           (ein:notebook-new "DUMMY-URL" notebook-id)
                           :data (ein:json-read-from-string json-string))
-      (let ((events (ein:events-new (current-buffer))))
-        (setf (ein:$notebook-events ein:notebook) events)
+      (let ((events (ein:$notebook-events ein:notebook)))
         (setf (ein:$notebook-kernel ein:notebook)
               (ein:kernel-new 8888 "/kernels" events)))
       (current-buffer))))

From dc21cd2f386afe65cf724fbb1cf61ec704dbb7fa Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sun, 17 Jun 2012 00:19:00 +0200
Subject: [PATCH 13/14] Update README and doc

Once this branch is merged, EIN will be "ready for release" state.
---
 README.rst           | 5 +++--
 doc/source/index.rst | 1 +
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/README.rst b/README.rst
index fce92ac..ecd2895 100644
--- a/README.rst
+++ b/README.rst
@@ -2,8 +2,9 @@
  Emacs IPython Notebook (and more)
 ===================================
 
-.. warning:: This is **very** early version.
-             Make sure you have backup!
+.. note:: It is stable enough for my day to day work, but I can't
+          grantee the safety for your notebook data.  So please make
+          sure you have backup.
 
 Screenshot
 ==========
diff --git a/doc/source/index.rst b/doc/source/index.rst
index 3d7b244..0481668 100644
--- a/doc/source/index.rst
+++ b/doc/source/index.rst
@@ -208,6 +208,7 @@ Notebook list
 Notebook
 ^^^^^^^^
 
+.. el:variable:: ein:notebook-enable-undo
 .. el:variable:: ein:notebook-discard-output-on-save
 .. el:variable:: ein:notebook-modes
 .. el:variable:: ein:notebook-kill-buffer-ask

From 1ef27808c52834bc9fbe17e3ee41551f47015954 Mon Sep 17 00:00:00 2001
From: Takafumi Arakaki <aka.tkf@gmail.com>
Date: Sun, 17 Jun 2012 01:12:13 +0200
Subject: [PATCH 14/14] Add dummy for maybe_reset_undo.Notebook in shared
 output

---
 ein-shared-output.el | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/ein-shared-output.el b/ein-shared-output.el
index 455b657..455a1af 100644
--- a/ein-shared-output.el
+++ b/ein-shared-output.el
@@ -109,8 +109,9 @@
       ein:@shared-output)))
 
 (defun ein:shared-output-bind-events (events)
-  (ein:events-on events 'set_dirty.Notebook
-                 (lambda (&rest ignore))))
+  "Add dummy event handlers."
+  (ein:events-on events 'set_dirty.Notebook (lambda (&rest ignore)))
+  (ein:events-on events 'maybe_reset_undo.Notebook (lambda (&rest ignore))))
 
 (defun ein:shared-output-get-cell ()
   "Get the singleton shared output cell.