adding a function for inspecting code block information e.g., header arguments

* lisp/ob.el (org-babel-view-src-block-info): New function to inspect code blocks.
* lisp/ob-keys.el (org-babel-key-bindings): Key bindings for org-babel-view-src-block-info.
* doc/orgcard.tex: Documentation of new Babel function.

doc/orgcard.tex

@@ -445,6 +445,7 @@ formula, \kbd{:=} a field formula.
 \key{open results of code block at point}{C-c C-o}
 \key{check code block at point for errors}{C-c C-v c}
 \key{view expanded body of code block at point}{C-c C-v v}
+\key{view information about code block at point}{C-c C-v I}
 \key{go to named code block}{C-c C-v g}
 \key{go to named result}{C-c C-v r}
 \key{go to the head of the current code block}{C-c C-v u}

lisp/ob-keys.el

@@ -79,6 +79,8 @@ functions which are assigned key bindings, and see
     ("l" . org-babel-load-in-session)
     ("\C-i" . org-babel-lob-ingest)
     ("i" . org-babel-lob-ingest)
+    ("\C-I" . org-babel-view-src-block-info)
+    ("I" . org-babel-view-src-block-info)
     ("\C-z" . org-babel-switch-to-session)
     ("z" . org-babel-switch-to-session-with-code)
     ("\C-a" . org-babel-sha1-hash)

lisp/ob.el

@@ -250,6 +250,34 @@ then run `org-babel-execute-src-block'."
 	(progn (org-babel-eval-wipe-error-buffer)
 	       (org-babel-execute-src-block current-prefix-arg info) t) nil)))
 
+;;;###autoload
+(defun org-babel-view-src-block-info ()
+  "Display information on the current source block.
+This includes header arguments, language and name, and is largely
+a window into the `org-babel-get-src-block-info' function."
+  (interactive)
+  (let ((info (org-babel-get-src-block-info 'light)))
+    (flet ((full (it) (> (length it) 0))
+	   (printf (fmt &rest args) (princ (apply #'format fmt args))))
+      (when info
+	(with-help-window (help-buffer)
+	  (let ((name        (nth 4 info))
+		(lang        (nth 0 info))
+		(switches    (nth 3 info))
+		(header-args (nth 2 info)))
+	    (when name            (printf "Name: %s\n"     name))
+	    (when lang            (printf "Lang: %s\n"     lang))
+	    (when (full switches) (printf "Switches: %s\n" switches))
+	    (printf "Header Arguments:\n")
+	    (dolist (pair (sort header-args
+				(lambda (a b) (string< (symbol-name (car a))
+						  (symbol-name (car b))))))
+	      (when (full (cdr pair))
+		(printf "\t%S%s\t%s\n"
+			(car pair)
+			(if (> (length (format "%S" (car pair))) 7) "" "\t")
+			(cdr pair))))))))))
+
 ;;;###autoload
 (defun org-babel-expand-src-block-maybe ()
   "Conditionally expand a source block.