Use 'match' to match on all the magic commands.

* guix-jupyter-kernel.scm (reply-execute-request): Use 'match' to
dispatch among all the magic, getting rid of (guix jupyter magic).

guix-jupyter-kernel.scm

@@ -44,7 +44,6 @@
              (guix jupyter logging)
              (guix jupyter proxy)
              (guix jupyter kernel)
-             (guix jupyter magic)
              (guix jupyter environment))
 
 (define session-id (random (* 255 255)
@@ -216,76 +215,71 @@ to KERNEL as a reply to MESSAGE, and return STATE suitably adjusted."
 (define (reply-execute-request kernel kind message state)
   (let* ((content (message-content message))
          (code    (assoc-ref (json-string->scm content) "code"))
-         (magic   (get-magic-line code))
+         (line    (string-take code
+                               (or (string-index code #\newline)
+                                   (string-length code))))
          (count   (proxy-state-execution-count state)))
-    (cond
-     ((magic-env? code)
-      (pub-busy kernel message)
-      (match (string-tokenize magic)
-        ((_ "environment" name "<-" specs ...)
-         (match (lookup-proxied name state)
-           (#f
-            (create-environment name specs state
-                                #:kernel kernel
-                                #:message message))
-           ((? kernel? proxy)
-            (format/log "terminating existing '~a' environment~%"
-                        name)
-            (unmonitor-client proxy)
-            (terminate-proxied-kernel proxy)
-            (create-environment name specs
-                                (unregister-proxied name state)
-                                #:kernel kernel
-                                #:message message))))
-        ((_ "environment" name)
-         (match (lookup-proxied name state)
-           (#f
-            (reply-html kernel message
-                        (sxml->html-string
-                         `(bold "Unknown environment "
-                                (code ,name) "."))
-                        count)
-            (increment-execution-count state))
-           ((? kernel? proxy)
-            (format/log "evaluating code in container ~s (PID ~s)~%"
-                        name (kernel-pid proxy))
-            (send-message proxy message)
-            (let ((state (increment-execution-count state)))
-              (set-proxy-state-default-environment state name)))))
-        ((lst ...)
-         (reply-html kernel message
-                     (sxml->html-string
-                      `(bold "Invalid " (code "guix environment")
-                             " magic."))
-                     count)
-         (increment-execution-count state))))
-     ((magic-html? code)
-      (reply-html kernel message (delete-magic code) count)
-      (increment-execution-count state))
-     ((proxy-state-default-environment state)
-      =>
-      (lambda (environment)
-        (let ((proxied (lookup-proxied environment state)))
-          (format/log "evaluating code in environment ~s (PID ~s)~%"
-                      environment (kernel-pid proxied))
-          (send-message proxied message
-                        #:kernel-socket kind)
-          (increment-execution-count state))))
-     (else
-      (reply-html kernel message
-                  (sxml->html-string
-                   `(div "You have not selected an execution environment
+    (pub-busy kernel message)
+    (match (string-tokenize line)
+      ((";;guix" "environment" name "<-" specs ...)
+       (match (lookup-proxied name state)
+         (#f
+          (create-environment name specs state
+                              #:kernel kernel
+                              #:message message))
+         ((? kernel? proxy)
+          (format/log "terminating existing '~a' environment~%"
+                      name)
+          (unmonitor-client proxy)
+          (terminate-proxied-kernel proxy)
+          (create-environment name specs
+                              (unregister-proxied name state)
+                              #:kernel kernel
+                              #:message message))))
+      ((";;guix" "environment" name)
+       (match (lookup-proxied name state)
+         (#f
+          (reply-html kernel message
+                      (sxml->html-string
+                       `(bold "Unknown environment "
+                              (code ,name) "."))
+                      count)
+          (increment-execution-count state))
+         ((? kernel? proxy)
+          (format/log "evaluating code in container ~s (PID ~s)~%"
+                      name (kernel-pid proxy))
+          (send-message proxy message)
+          (let ((state (increment-execution-count state)))
+            (set-proxy-state-default-environment state name)))))
+      ((";;guix" _ ...)
+       (reply-html kernel message
+                   (sxml->html-string
+                    `(bold "Invalid " (code "guix") " magic."))
+                   count)
+       (increment-execution-count state))
+      (_
+       (match (proxy-state-default-environment state)
+         ((? string? environment)
+          (let ((proxied (lookup-proxied environment state)))
+            (format/log "evaluating code in environment ~s (PID ~s)~%"
+                        environment (kernel-pid proxied))
+            (send-message proxied message #:kernel-socket kind)
+            (increment-execution-count state)))
+         (#f
+          (reply-html kernel message
+                      (sxml->html-string
+                       `(div "You have not selected an execution environment
 yet.  You can create one by entering a “magic command” in a cell as follows:"
-                         (p (code ";;guix environment my-environment <- \
+                             (p (code ";;guix environment my-environment <- \
 python-ipython python-ipykernel"))
-                         "You can then select a kernel and hand it code
+                             "You can then select a kernel and hand it code
 to execute:"
-                         (p (pre
-                             (code
-                              ";;guix kernel my-environment ipython\n"
-                              "2 + 2")))))
-                  count)
-      state))))
+                             (p (pre
+                                 (code
+                                  ";;guix kernel my-environment ipython\n"
+                                  "2 + 2")))))
+                      count)
+          state))))))
 
 (define (shutdown kernel kind message state)
   (format/log "shutting down ~a containers~%"