* Prevent creating empty lines with trailing spaces when tangling noweb
@ 2017-05-06 6:30 Kaushal Modi
2017-05-06 6:54 ` Kaushal Modi
2017-05-06 7:23 ` Nicolas Goaziou
0 siblings, 2 replies; 4+ messages in thread
From: Kaushal Modi @ 2017-05-06 6:30 UTC (permalink / raw)
To: emacs-org list
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Hello,
I have this MWE:
#+TITLE: Org babel tangle and noweb
#+PROPERTY: header-args:shell :shebang "#!/usr/bin/env bash"
* Shell Script
#+BEGIN_SRC shell :noweb yes :tangle code.sh
exec emacs -Q "$@" \
--eval '(progn
<<elisp>>
)' 2>/dev/null </dev/tty
#+END_SRC
* Emacs Configuration
#+BEGIN_SRC emacs-lisp :noweb-ref elisp :noweb-sep "\\n\\n"
(menu-bar-mode -1)
#+END_SRC
Some comment.
#+BEGIN_SRC emacs-lisp :noweb-ref elisp
(line-number-mode 1)
#+END_SRC
When tangled (C-c C-v t), it generates:
[image: image.png]
Notice that the empty line is created between noweb segments as expected
because of ":noweb-sep "\\n\\n"". But what was unexpected to me was the
creation of empty line with spaces inserted to match the indentation.
Is this by design?
If it is by design, I would propose to have a new switch called something
like ":noweb-notrailingspc" (would like a better suggestion for this switch
name).
So the src block where noweb expansion needs to happen will look like this:
#+BEGIN_SRC shell :noweb yes :tangle code.sh :noweb-notrailingspc yes
exec emacs -Q "$@" \
--eval '(progn
<<elisp>>
)' 2>/dev/null </dev/tty
#+END_SRC
Now, tangling will generate
[image: image.png]
Here is a diff (without whitespace differences) of the change I made to
ob-core locally to get this:
diff --git a/lisp/ob-core.el b/lisp/ob-core.el
index cb332ffea92..0f04d8b85e1 100644
--- a/lisp/ob-core.el
+++ b/lisp/ob-core.el
@@ -2730,9 +2730,7 @@ block but are passed literally to the
\"example-block\"."
(funcall nb-add (buffer-substring index (point)))
(goto-char (match-end 0))
(setq index (point))
- (funcall
- nb-add
- (with-current-buffer parent-buffer
+ (let ((body-str (with-current-buffer parent-buffer
(save-restriction
(widen)
(mapconcat ;; Interpose PREFIX between every line.
@@ -2794,6 +2792,9 @@ block but are passed literally to the
\"example-block\"."
"`org-babel-noweb-error-langs')"))
"")))
"[\n\r]") (concat "\n" prefix))))))
+ (when (string= "yes" (cdr (assq :noweb-notrailingspc (nth 2 info))))
+ (setq body-str (replace-regexp-in-string "^[ \n\r]*\n" "\n" body-str)))
+ (funcall nb-add body-str)))
(funcall nb-add (buffer-substring index (point-max))))
new-body))
Questions:
1. If the above empty lines with prefix number of spaces are not expected,
the fix would be simpler.. to just throw in that (setq body-str
(replace-regexp-in-string "^[ \n\r]*\n" "\n" body-str)) form in-between.
2a. If the spacey empty lines are as per design, then does this diff look
good? Should I work on a proper patch?
2b. What would be a better/more intuitive switch name than
":noweb-notrailingspc"?
--
Kaushal Modi
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: Prevent creating empty lines with trailing spaces when tangling noweb
2017-05-06 6:30 Prevent creating empty lines with trailing spaces when tangling noweb Kaushal Modi
@ 2017-05-06 6:54 ` Kaushal Modi
2017-05-06 7:23 ` Nicolas Goaziou
1 sibling, 0 replies; 4+ messages in thread
From: Kaushal Modi @ 2017-05-06 6:54 UTC (permalink / raw)
To: emacs-org list
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On Sat, May 6, 2017 at 2:30 AM Kaushal Modi <kaushal.modi@gmail.com> wrote:
> + (setq body-str (replace-regexp-in-string "^[ \n\r]*\n" "\n"
> body-str)))
>
>
Just one correction to this regexp so that two or more consecutive empty
lines in the source block get retained:
(setq body-str (replace-regexp-in-string "^[ ]+\n" "\n" body-str))
Here's the draft diff again:
diff --git a/lisp/ob-core.el b/lisp/ob-core.el
index cb332ffea92..96628f44ab4 100644
--- a/lisp/ob-core.el
+++ b/lisp/ob-core.el
@@ -2730,9 +2730,7 @@ block but are passed literally to the
\"example-block\"."
(funcall nb-add (buffer-substring index (point)))
(goto-char (match-end 0))
(setq index (point))
- (funcall
- nb-add
- (with-current-buffer parent-buffer
+ (let ((body-str (with-current-buffer parent-buffer
(save-restriction
(widen)
(mapconcat ;; Interpose PREFIX between every line.
@@ -2794,6 +2792,9 @@ block but are passed literally to the
\"example-block\"."
"`org-babel-noweb-error-langs')"))
"")))
"[\n\r]") (concat "\n" prefix))))))
+ (when (string= "yes" (cdr (assq :noweb-notrailingspc (nth 2 info))))
+ (setq body-str (replace-regexp-in-string "^[ ]+\n" "\n" body-str)))
+ (funcall nb-add body-str)))
(funcall nb-add (buffer-substring index (point-max))))
new-body))
--
Kaushal Modi
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: Prevent creating empty lines with trailing spaces when tangling noweb
2017-05-06 6:30 Prevent creating empty lines with trailing spaces when tangling noweb Kaushal Modi
2017-05-06 6:54 ` Kaushal Modi
@ 2017-05-06 7:23 ` Nicolas Goaziou
2017-05-06 12:59 ` Kaushal Modi
1 sibling, 1 reply; 4+ messages in thread
From: Nicolas Goaziou @ 2017-05-06 7:23 UTC (permalink / raw)
To: Kaushal Modi; +Cc: emacs-org list
Hello,
Kaushal Modi <kaushal.modi@gmail.com> writes:
> Notice that the empty line is created between noweb segments as expected
> because of ":noweb-sep "\\n\\n"". But what was unexpected to me was the
> creation of empty line with spaces inserted to match the indentation.
>
> Is this by design?
I lean towards "yes".
> If it is by design, I would propose to have a new switch called something
> like ":noweb-notrailingspc" (would like a better suggestion for this switch
> name).
I don't think this is necessary. This is but a corner-case. That doesn't
require a dedicated switch.
I'd rather clean every empty line upon tangling, or let the user do it
with `org-babel-post-tangle-hook'.
Regards,
--
Nicolas Goaziou
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Prevent creating empty lines with trailing spaces when tangling noweb
2017-05-06 7:23 ` Nicolas Goaziou
@ 2017-05-06 12:59 ` Kaushal Modi
0 siblings, 0 replies; 4+ messages in thread
From: Kaushal Modi @ 2017-05-06 12:59 UTC (permalink / raw)
To: Nicolas Goaziou; +Cc: emacs-org list
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On Sat, May 6, 2017, 3:23 AM Nicolas Goaziou <mail@nicolasgoaziou.fr> wrote:
> Hello,
>
> Kaushal Modi <kaushal.modi@gmail.com> writes:
>
> I'd rather clean every empty line upon tangling, or let the user do it
> with `org-babel-post-tangle-hook'.
I just tried this again and it worked this time!
(add-hook 'org-babel-post-tangle-hook #'delete-trailing-whitespace)
(add-hook 'org-babel-post-tangle-hook #'save-buffer :append)
Thanks!
Some back-story on what led me to modify ob-core.el:
I did try changing the hook earlier, but that did not work. So this was my
next attempt[1], and that led me to try this approach of preventing white
spaces in the first place.
Earlier I was also trying to tangle using ox-publish with this element in
org-publish-project-alist:
("foo"
:base-directory "/some/dir"
:publishing-function org-babel-tangle-publish
:publishing-directory "/some/dir")
Probably the base directory and publishing directory being the same caused
some issue with saving the buffer after delete-trailing-whitespace. So I
ended up having to manually save the tangled file after each publish step.
Or probably I somehow didn't have the hooks right.
After that I switched to calling just the below separately instead of
tangling through publish step:
(org-babel-tangle file FILE)
And now with the above hook modifications, the deletion of whitespaces is
working exactly as I wanted.
Well, that was an interesting journey.
[1]:
https://github.com/kaushalmodi/eless/blob/aa060eaede906e6bd4205f997074e7048c0c810c/build/build.el#L28-L47
--
Kaushal Modi
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-05-06 6:30 Prevent creating empty lines with trailing spaces when tangling noweb Kaushal Modi
2017-05-06 6:54 ` Kaushal Modi
2017-05-06 7:23 ` Nicolas Goaziou
2017-05-06 12:59 ` Kaushal Modi
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