Clean up various org-babel-*-maybe commands

* lisp/ob-core.el (org-babel-when-in-src-block): New macro.
  (org-babel-execute-src-block-maybe)
  (org-babel-expand-src-block-maybe)
  (org-babel-load-in-session-maybe, org-babel-pop-to-session-maybe):
  Use it.

org-babel-get-src-block-info is a potentially expensive operation, which
is why its ‘light’ argument exists.  But in any case, it is overkill to
query the whole info, if all that is needed is whether point is in a
block or not.  Factor the simplified common code out into a macro.

lisp/ob-core.el

@@ -351,15 +351,25 @@ of potentially harmful code."
   (or (org-babel-execute-src-block-maybe)
       (org-babel-lob-execute-maybe)))
 
+(defmacro org-babel-when-in-src-block (&rest body)
+  "Execute BODY if point is in a source block and return t.
+
+Otherwise do nothing and return nil."
+  `(if (or (org-babel-where-is-src-block-head)
+           (org-babel-get-inline-src-block-matches))
+       (progn
+	 ,@body
+	 t)
+     nil))
+
 (defun org-babel-execute-src-block-maybe ()
   "Conditionally execute a source block.
 Detect if this is context for a Babel src-block and if so
 then run `org-babel-execute-src-block'."
   (interactive)
-  (let ((info (org-babel-get-src-block-info)))
-    (if info
-	(progn (org-babel-eval-wipe-error-buffer)
-	       (org-babel-execute-src-block current-prefix-arg info) t) nil)))
+  (org-babel-when-in-src-block
+   (org-babel-eval-wipe-error-buffer)
+   (org-babel-execute-src-block current-prefix-arg)))
 
 ;;;###autoload
 (defun org-babel-view-src-block-info ()
@@ -395,10 +405,8 @@ a window into the `org-babel-get-src-block-info' function."
 Detect if this is context for a org-babel src-block and if so
 then run `org-babel-expand-src-block'."
   (interactive)
-  (let ((info (org-babel-get-src-block-info)))
-    (if info
-	(progn (org-babel-expand-src-block current-prefix-arg info) t)
-      nil)))
+  (org-babel-when-in-src-block
+   (org-babel-expand-src-block current-prefix-arg)))
 
 ;;;###autoload
 (defun org-babel-load-in-session-maybe ()
@@ -406,10 +414,8 @@ then run `org-babel-expand-src-block'."
 Detect if this is context for a org-babel src-block and if so
 then run `org-babel-load-in-session'."
   (interactive)
-  (let ((info (org-babel-get-src-block-info)))
-    (if info
-	(progn (org-babel-load-in-session current-prefix-arg info) t)
-      nil)))
+  (org-babel-when-in-src-block
+   (org-babel-load-in-session current-prefix-arg)))
 
 (add-hook 'org-metaup-hook 'org-babel-load-in-session-maybe)
 
@@ -419,8 +425,8 @@ then run `org-babel-load-in-session'."
 Detect if this is context for a org-babel src-block and if so
 then run `org-babel-pop-to-session'."
   (interactive)
-  (let ((info (org-babel-get-src-block-info)))
-    (if info (progn (org-babel-pop-to-session current-prefix-arg info) t) nil)))
+  (org-babel-when-in-src-block
+   (org-babel-switch-to-session current-prefix-arg)))
 
 (add-hook 'org-metadown-hook 'org-babel-pop-to-session-maybe)