[Orgmode] [PATCH] Allow no stripping of blank lines from code

[Dan Davison]

Now that we can issue TAB in a code block and have it act according to
language [see org-src-tab-acts-natively], the following is a minor
frustration: if you try to insert a blank line at the beginning/end of
the block (perhaps to introduce a new first/last line), then on TAB it
disappears because org-edit-src-exit strips leading and trailing blank
lines. This patch introduces a variable that turns off that behaviour.

The default is still to strip lines. I am slightly wondering what the
reason for that default was. I can see it could be useful for
artist-mode, but for genuine code blocks should the default be to give
the user responsibility for curating leading/trailing blank lines?

Dan

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commit 84503c83d143b40bded8122e45ffba703c4035a1
Author: Dan Davison <address@hidden>
Date:   Sun Sep 5 18:55:06 2010 -0400

    Optionally prevent stripping of blank lines from code blocks
    
        * org-src.el (org-edit-src-exit): Only strip leading and
        trailing blank lines if
        `org-src-strip-leading-and-trailing-blank-lines' is non-nil
        (org-src-strip-leading-and-trailing-blank-lines): New variable

diff --git a/lisp/org-src.el b/lisp/org-src.el
index f11eec2..d877925 100644
--- a/lisp/org-src.el
+++ b/lisp/org-src.el
@@ -109,6 +109,12 @@ editing it with \\[org-edit-src-code].  Has no effect if
   :group 'org-edit-structure
   :type 'integer)
 
+(defcustom org-src-strip-leading-and-trailing-blank-lines t
+  "If non-nil, blank lines are removed when exiting the code edit
+buffer."
+  :group 'org-edit-structure
+  :type 'boolean)
+
 (defcustom org-edit-src-persistent-message t
   "Non-nil means show persistent exit help message while editing src examples.
 The message is shown in the header-line, which will be created in the
@@ -577,11 +583,12 @@ the language, a switch telling if the content should be 
in a single line."
         (delta 0) code line col indent)
     (when allow-write-back-p
       (unless preserve-indentation (untabify (point-min) (point-max)))
-      (save-excursion
-       (goto-char (point-min))
-       (if (looking-at "[ \t\n]*\n") (replace-match ""))
-       (unless macro
-         (if (re-search-forward "\n[ \t\n]*\\'" nil t) (replace-match "")))))
+      (if org-src-strip-leading-and-trailing-blank-lines
+         (save-excursion
+           (goto-char (point-min))
+           (if (looking-at "[ \t\n]*\n") (replace-match ""))
+           (unless macro
+             (if (re-search-forward "\n[ \t\n]*\\'" nil t) (replace-match 
""))))))
     (setq line (if (org-bound-and-true-p org-edit-src-force-single-line)
                   1
                 (org-current-line))
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