ob-core: Add org-babel-uppercase-example-markers option

* lisp/ob-core.el (org-babel-capitalize-example-region-markers): Mark
as obsolete.
(org-babel-uppercase-example-markers): New defcustom to replace defvar
org-babel-capitalize-example-region-markers.
(org-babel-examplify-region): Use new option.

Rather than moving org-babel-capitalize-example-region-markers to a
defcustom, give the option a new name that makes it clearer that all
characters, not just the first, will be in upper case.

Suggested-by: Vicente Vera <vicentemvp@gmail.com>
<http://permalink.gmane.org/gmane.emacs.orgmode/111656>

etc/ORG-NEWS

@@ -218,6 +218,13 @@ document with ~org-mark-ring-goto~ (default binding =C-c &=).
 *** ~org-get-heading~ accepts two more optional arguments
 
 See docstring for details.
+
+*** New option ~org-babel-uppercase-example-markers~
+
+This variable is a ~defcustom~ and replaces the variable
+~org-babel-capitalize-example-region-markers~, which is a ~defvar~ and
+is now obselete.
+
 * Version 9.0
 
 ** Incompatible changes

lisp/ob-core.el

@@ -179,6 +179,14 @@ This string must include a \"%s\" which will be replaced by the results."
   :package-version '(Org . "9.0")
   :safe #'booleanp)
 
+(defcustom org-babel-uppercase-example-markers nil
+  "When non-nil, begin/end example markers will be inserted in upper case."
+  :group 'org-babel
+  :type 'boolean
+  :version "26.1"
+  :package-version '(Org . "9.1")
+  :safe #'booleanp)
+
 (defun org-babel-noweb-wrap (&optional regexp)
   (concat org-babel-noweb-wrap-start
 	  (or regexp "\\([^ \t\n].+?[^ \t]\\|[^ \t\n]\\)")
@@ -2435,15 +2443,12 @@ file's directory then expand relative links."
 	      result)
 	    (if description (concat "[" description "]") ""))))
 
-(defvar org-babel-capitalize-example-region-markers nil
-  "Make true to capitalize begin/end example markers inserted by code blocks.")
-
 (defun org-babel-examplify-region (beg end &optional results-switches inline)
   "Comment out region using the inline `==' or `: ' org example quote."
   (interactive "*r")
   (let ((maybe-cap
 	 (lambda (str)
-	   (if org-babel-capitalize-example-region-markers (upcase str) str))))
+	   (if org-babel-uppercase-example-markers (upcase str) str))))
     (if inline
 	(save-excursion
 	  (goto-char beg)

lisp/org-compat.el

@@ -195,6 +195,9 @@ Counting starts at 1."
   'org-agenda-today-p "Org 9.0")
 (define-obsolete-function-alias 'org-babel-examplize-region
   'org-babel-examplify-region "Org 9.0")
+(define-obsolete-variable-alias 'org-babel-capitalize-example-region-markers
+  'org-babel-uppercase-example-markers "Org 9.1")
+
 (define-obsolete-function-alias 'org-babel-trim 'org-trim "Org 9.0")
 (define-obsolete-variable-alias 'org-html-style 'org-html-head "24.4")
 (define-obsolete-function-alias 'org-insert-columns-dblock