ob-core: Display babel execution time

* lisp/ob-core.el (org-babel-execute-src-block,
org-babel-format-result): Record the babel execution time, and then
supplement the "Code block evaluation complete." (etc.) messages with
the execution time when >0.05s.

Author: tecosaur

lisp/ob-core.el

@@ -789,7 +789,7 @@ guess will be made."
 		       (make-directory d 'parents)
 		       d))))
 		 (cmd (intern (concat "org-babel-execute:" lang)))
-		 result)
+		 result exec-start-time)
 	    (unless (fboundp cmd)
 	      (error "No org-babel-execute function for %s!" lang))
 	    (message "executing %s %s %s..."
@@ -804,7 +804,8 @@ guess will be made."
 		       (if name
                            (format "(%s)" name)
                          (format "at position %d" (nth 5 info)))))
-	    (setq result
+	    (setq exec-start-time (current-time)
+                  result
 		  (let ((r (funcall cmd body params)))
 		    (if (and (eq (cdr (assq :result-type params)) 'value)
 			     (or (member "vector" result-params)
@@ -847,7 +848,8 @@ guess will be made."
 	      (if (member "none" result-params)
 		  (message "result silenced")
 	        (org-babel-insert-result
-	         result result-params info new-hash lang)))
+	         result result-params info new-hash lang
+                 (time-subtract (current-time) exec-start-time))))
 	    (run-hooks 'org-babel-after-execute-hook)
 	    result)))))))
 
@@ -2258,15 +2260,16 @@ If the path of the link is a file path it is expanded using
       ;; scalar result
       (funcall echo-res result))))
 
-(defun org-babel-insert-result (result &optional result-params info hash lang)
+(defun org-babel-insert-result (result &optional result-params info hash lang exec-time)
   "Insert RESULT into the current buffer.
 
 By default RESULT is inserted after the end of the current source
 block.  The RESULT of an inline source block usually will be
 wrapped inside a `results' macro and placed on the same line as
 the inline source block.  The macro is stripped upon export.
 Multiline and non-scalar RESULTS from inline source blocks are
-not allowed.  With optional argument RESULT-PARAMS controls
+not allowed.  When EXEC-TIME is provided it may be included in a
+generated message.  With optional argument RESULT-PARAMS controls
 insertion of results in the Org mode file.  RESULT-PARAMS can
 take the following values:
 
@@ -2571,11 +2574,18 @@ INFO may provide the values of these header arguments (in the
 			   (not (and (listp result)
 				     (member "append" result-params))))
 		  (indent-rigidly beg end indent))
-		(if (null result)
-		    (if (member "value" result-params)
-			(message "Code block returned no value.")
-		      (message "Code block produced no output."))
-		  (message "Code block evaluation complete.")))
+                (let ((time-info
+                       ;; Only show the time when something other than
+                       ;; 0s will be shown, i.e. check if the time is at
+                       ;; least half of the displayed precision.
+                       (if (and exec-time (> (float-time exec-time) 0.05))
+                           (format " (took %.1fs)" (float-time exec-time))
+                         "")))
+                  (if (null result)
+                      (if (member "value" result-params)
+                          (message "Code block returned no value%s." time-info)
+                        (message "Code block produced no output%s." time-info))
+                    (message "Code block evaluation complete%s." time-info))))
 	    (set-marker end nil)
 	    (when outside-scope (narrow-to-region visible-beg visible-end))
 	    (set-marker visible-beg nil)