[org] create async tangle command

init.org

@@ -1362,6 +1362,7 @@ _u_: next word       ^_l_: edit lines^      _s_: next whole symbol
   ("b" cp-org-block/body "source block")
   ("t" cp-org-set-tags "tags")
   ("n" cp-org-nav/body "navigation")
+  ("B" contrapunctus-async-tangle "babel-tangle")
 
   ("0" delete-window "delete this" :color red)
   ("1" delete-other-windows "delete others" :color red)
@@ -1445,6 +1446,7 @@ _u_: next word       ^_l_: edit lines^      _s_: next whole symbol
   ("j" xref-find-definitions "Jump to definition")
   ("J" org-babel-tangle-jump-to-org "Jump to definition (Org)")
   ("t" (contrapunctus-el-test/body) "Test")
+  ("B" contrapunctus-async-tangle "babel-tangle")
 
   ("0" delete-window "delete this" :color red)
   ("1" delete-other-windows "delete others" :color red)
@@ -2712,6 +2714,29 @@ pjb suggested a different approach [[http://paste.lisp.org/display/10157][here]]
   :commands explain-pause-mode
   :init (explain-pause-mode))
 #+END_SRC
+**** async-tangle
+#+BEGIN_SRC emacs-lisp
+(defun contrapunctus-async-tangle (&optional prefix)
+  (interactive "P")
+  (let ((proc-buffer (get-buffer-create "*async-tangle-process*"))
+        (file-name (buffer-file-name))
+        (file-name-no-ext (file-name-sans-extension
+                           (buffer-file-name)))
+        (old-win (selected-window))
+        (new-win (split-window-below)))
+    (start-process
+     "async-tangle" proc-buffer "emacs" "-q" "-Q" "--batch"
+     "--eval=(require 'ob-tangle)"
+     (format "--eval=(org-babel-tangle-file \"%s\")"
+             file-name file-name-no-ext))
+    ;; to avoid messing up my usual two-windows-same-buffer setup
+    (select-window new-win)
+    (switch-to-buffer proc-buffer)
+    ;; so I can access my Hydra to switch back
+    (boon-mode)
+    (select-window old-win)))
+
+#+END_SRC
 *** Common Lisp
 #+BEGIN_SRC emacs-lisp
 (use-package redshank