From f92e14f62bade2c1988b34c21b78017eca8b0670 Mon Sep 17 00:00:00 2001
From: Nathaniel Nicandro <nathanielnicandro@gmail.com>
Date: Sun, 13 Dec 2020 16:18:20 -0600
Subject: [PATCH] Add `jupyter-restart-kernel`

---
 jupyter-client.el        | 8 ++++++++
 jupyter-kernel.el        | 7 +++++--
 jupyter-server-kernel.el | 7 +++++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/jupyter-client.el b/jupyter-client.el
index b2338fd..55c313a 100644
--- a/jupyter-client.el
+++ b/jupyter-client.el
@@ -473,6 +473,14 @@ longer connected to a kernel."
         (jupyter-publish 'shutdown))
       (jupyter-disconnect client))))
 
+(cl-defmethod jupyter-restart-kernel ((client jupyter-kernel-client))
+  "Restart the kernel CLIENT is connected to."
+  (when (jupyter-connected-p client)
+    (pcase-let ((`(,_ ,kaction-sub) (oref client io)))
+      (jupyter-run-with-io kaction-sub
+        (jupyter-publish 'restart))
+      (jupyter-disconnect client))))
+
 (cl-defmethod jupyter-interrupt-kernel ((client jupyter-kernel-client))
   "Interrupt the kernel CLIENT is connected to."
   (when (jupyter-connected-p client)
diff --git a/jupyter-kernel.el b/jupyter-kernel.el
index e9f910d..db3d544 100644
--- a/jupyter-kernel.el
+++ b/jupyter-kernel.el
@@ -125,8 +125,11 @@ nil."
   "Notify that the kernel launched."
   (message "%s kernel shutdown...done" (jupyter-kernel-name kernel)))
 
-(defun jupyter-restart (kernel)
-  "Shutdown then re-launch KERNEL."
+(cl-defgeneric jupyter-restart ((kernel jupyter-kernel))
+  "Restart KERNEL.
+
+The default implementation shuts down and then re-launches
+KERNEL."
   (jupyter-shutdown kernel)
   (jupyter-launch kernel))
 
diff --git a/jupyter-server-kernel.el b/jupyter-server-kernel.el
index e9a3b81..407ea8e 100644
--- a/jupyter-server-kernel.el
+++ b/jupyter-server-kernel.el
@@ -282,6 +282,8 @@ this case FN will be evaluated on KERNEL."
                  (jupyter-shutdown kernel)
                  (websocket-close ws)
                  (setq shutdown t))
+                ('restart
+                 (jupyter-restart kernel))
                 (`(action ,fn)
                  (funcall fn kernel))))))))
 
@@ -333,6 +335,11 @@ using its SPEC."
     (when session
       (jupyter-api-shutdown-kernel server id))))
 
+(cl-defmethod jupyter-restart ((kernel jupyter-server-kernel))
+  (pcase-let (((cl-struct jupyter-server-kernel server id session) kernel))
+    (when session
+      (jupyter-api-restart-kernel server id))))
+
 (cl-defmethod jupyter-interrupt ((kernel jupyter-server-kernel))
   (pcase-let (((cl-struct jupyter-server-kernel server id) kernel))
     (jupyter-api-interrupt-kernel server id)))