Re: [O] export to org, header args disappear

[Aaron Ecay]

Hello Bastien and Brady,

The babel/export interface does not attempt to manage the header args
when it rewrites source blocks.  I think this code is pretty subtle.
Check out the (let (... (replacement ...)) ...) code in
‘org-babel-exp-process-buffer’ and the attached patch which fixes the
problem (superficially; I’m not sure if it’s the correct fundamental
approach).

>From 7faf58afa659cf63042464dbd15ad62239416832 Mon Sep 17 00:00:00 2001
From: Aaron Ecay <address@hidden>
Date: Wed, 21 May 2014 01:58:18 -0400
Subject: [PATCH] ox-org: fix export of source blocks with header args

---
 lisp/ob-exp.el              | 52 +++++++++++++++++++++++++--------------------
 testing/lisp/test-ob-exp.el |  6 +++---
 2 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/lisp/ob-exp.el b/lisp/ob-exp.el
index 220a3c3..ce45d84 100644
--- a/lisp/ob-exp.el
+++ b/lisp/ob-exp.el
@@ -311,7 +311,7 @@ The function respects the value of the :exports header 
argument."
             (org-babel-exp-code info)))))
 
 (defcustom org-babel-exp-code-template
-  "#+BEGIN_SRC %lang%switches%flags\n%body\n#+END_SRC"
+  "#+BEGIN_SRC %lang%switches%params\n%body\n#+END_SRC"
   "Template used to export the body of code blocks.
 This template may be customized to include additional information
 such as the code block name, or the values of particular header
@@ -322,7 +322,7 @@ and the following %keys may be used.
  name ------ the name of the code block
  body ------ the body of the code block
  switches -- the switches associated to the code block
- flags ----- the flags passed to the code block
+ params ---- the parameters passed to the code block
 
 In addition to the keys mentioned above, every header argument
 defined for the code block may be used as a key and will be
@@ -332,27 +332,33 @@ replaced with its value."
 
 (defun org-babel-exp-code (info)
   "Return the original code block formatted for export."
-  (setf (nth 1 info)
-       (if (string= "strip-export" (cdr (assoc :noweb (nth 2 info))))
-           (replace-regexp-in-string
-            (org-babel-noweb-wrap) "" (nth 1 info))
-         (if (org-babel-noweb-p (nth 2 info) :export)
-             (org-babel-expand-noweb-references
-              info org-babel-exp-reference-buffer)
-           (nth 1 info))))
-  (org-fill-template
-   org-babel-exp-code-template
-   `(("lang"  . ,(nth 0 info))
-     ("body"  . ,(org-escape-code-in-string (nth 1 info)))
-     ("switches" . ,(let ((f (nth 3 info)))
-                     (and (org-string-nw-p f) (concat " " f))))
-     ("flags" . ,(let ((f (assq :flags (nth 2 info))))
-                  (and f (concat " " (cdr f)))))
-     ,@(mapcar (lambda (pair)
-                (cons (substring (symbol-name (car pair)) 1)
-                      (format "%S" (cdr pair))))
-              (nth 2 info))
-     ("name"  . ,(or (nth 4 info) "")))))
+  ;; Here we assume that point is in the source block, an assumption
+  ;; we inherit from `org-babel-exp-src-block'.
+  (let* ((sb (org-element-at-point))
+        (params (org-element-property :parameters sb)))
+    (setf (nth 1 info)
+         (if (string= "strip-export" (cdr (assoc :noweb (nth 2 info))))
+             (replace-regexp-in-string
+              (org-babel-noweb-wrap) "" (nth 1 info))
+           (if (org-babel-noweb-p (nth 2 info) :export)
+               (org-babel-expand-noweb-references
+                info org-babel-exp-reference-buffer)
+             (nth 1 info))))
+    (org-fill-template
+     org-babel-exp-code-template
+     `(("lang"  . ,(nth 0 info))
+       ("body"  . ,(org-escape-code-in-string (nth 1 info)))
+       ("switches" . ,(let ((f (nth 3 info)))
+                       (and (org-string-nw-p f) (concat " " f))))
+       ("flags" . ,(let ((f (assq :flags (nth 2 info))))
+                    (and f (concat " " (cdr f)))))
+       ("params" . ,(when (and params (not (string= params "")))
+                     (concat " " params)))
+       ,@(mapcar (lambda (pair)
+                  (cons (substring (symbol-name (car pair)) 1)
+                        (format "%S" (cdr pair))))
+                (nth 2 info))
+       ("name"  . ,(or (nth 4 info) ""))))))
 
 (defun org-babel-exp-results (info type &optional silent hash)
   "Evaluate and return the results of the current code block for export.
diff --git a/testing/lisp/test-ob-exp.el b/testing/lisp/test-ob-exp.el
index 1fe810b..b5738d5 100644
--- a/testing/lisp/test-ob-exp.el
+++ b/testing/lisp/test-ob-exp.el
@@ -289,7 +289,7 @@ Here is one at the end of a line. =2=
 : 2
 
 #+NAME: src1
-#+BEGIN_SRC emacs-lisp
+#+BEGIN_SRC emacs-lisp :exports both
 \(+ 1 1)
 #+END_SRC"
     (org-test-with-temp-text
@@ -316,9 +316,9 @@ Here is one at the end of a line. =2=
   "Test exporting a source block with a flag."
   (should
    (string-match
-    "\\`#\\+BEGIN_SRC emacs-lisp -some-flag$"
+    "\\`#\\+BEGIN_SRC emacs-lisp -x$"
     (org-test-with-temp-text
-       "#+BEGIN_SRC emacs-lisp :flags -some-flag\n\(+ 1 1)\n#+END_SRC"
+       "#+BEGIN_SRC emacs-lisp -x\n\(+ 1 1)\n#+END_SRC"
       (org-export-execute-babel-code)
       (buffer-string)))))
 
-- 
1.9.3

--
Aaron Ecay