Re: Shouldn't ob-shell's org-babel-expand-src-block prepend the :shebang value?

[Vladimir Nikishkin]

Well, why exactly Racket people decided to introduce the #lang
directive in such a way that it looks like a shell comment or a
shebang line seems to elude my understanding.
(declare :lang 'whatever), at least to me, seems much more lispy, and
even (read) able by a standard reader (which could later be switched
to a different mode).

>because the shebang line will not actually be included when executing the code

How so? I never had problems using shebangs in my code. They seem to
be prepended to the autogenerated files in /tmp/org-* just fine (in
some other function).


>due to the addition of a prologue section

When does this happen? :prologue seems to be already included in the
'expanded variable.

>It also becomes necessary to remove the shebang line from the edit buffer

C-c C-v C-v does not make an edit buffer. It expands the buffer for a
preview. I never suggested to prepend a shebang to the C-' buffer. In
fact, saving the C-c C-v C-v buffer is the only reasonable thing you
can do to it. Editing it makes no direct sense, because expansion is a
many-to-one process, and you cannot "unexpand" the buffer (without
evil diff trickery at least).

>the need to keep what will be run by org babel in line

This actually _is_ about keeping the two things in line. When
evaluating a noweb-enabled block, and in fact, any block, org already
prepends the :shebang value. I'm just suggesting to make the preview
consistent


On Thu, 10 Sep 2020 at 15:11, Tom Gillespie <tgbugs@gmail.com> wrote:
>
> Hi Vladimir,
>    I have encountered similar issues with wanting to have a racket
> #lang line included in a tangled block while also allowing org to know
> exactly which #lang it is working with. I haven't found a good
> solution. One issue with embedding the shebang when editing a buffer
> is that it is very likely to cause confusion because the shebang line
> will not actually be included when executing the code, or if it was
> included then there is a reasonable possibility that in some cases it
> would not be included as the first line due to the addition of a
> prologue section. It also becomes necessary to remove the shebang line
> from the edit buffer, which means you have to know which shebang lines
> were added automatically and which were not. Further, the need to keep
> what will be run by org babel in line with what is shown via these
> various views makes it seem unlikely that this should be implemented
> as default behavior. I have a long email that touches on these issues
> in the works for after the 9.4 release, so thank you for providing an
> excellent example. It seems like one possible solution for your
> workflow would be to advise org-babel-expand-src-block to insert the
> shebang. Best,
> Tom
>
> On Wed, Sep 9, 2020 at 11:53 PM Vladimir Nikishkin <lockywolf@gmail.com> 
> wrote:
> >
> > So, my point is the following. A shebang is an almost universally
> > accepted way to specify which interpreter should be used for code
> > evaluation.
> >
> > In the ob-core.el, at line 787, the function called
> > org-babel-expand-src-block makes a buffer out of the noweb-expanded
> > code.
> > (I am working with org 20200907)
> >
> > The sexp is looking like this:
> >
> > (org-edit-src-code
> >      expanded (concat "*Org-Babel Preview " (buffer-name) "[ " lang " ]*"))
> >
> > I suggest replacing this sexp with
> >
> > (org-edit-src-code
> >      (seq-concatenate 'string (or (alist-get :shebang params) "") "\n"
> > expanded) (concat "*Org-Babel Preview " (buffer-name) "[ " lang "
> > ]*"))
> >
> > This way the expanded buffer would respect the shebang, and the
> > resulting buffer would be saveable as a runnable file.
> >
> > I suspect that the second branch of the (if) should be left as it is,
> > because non-interactive usage probably means that the code will be
> > used later as a part of something, and therefore does not need a
> > shebang.
> >
> > Vlad
> >
> > On Sat, 5 Sep 2020 at 15:13, Bastien <bzg@gnu.org> wrote:
> > >
> > > Vladimir Nikishkin <lockywolf@gmail.com> writes:
> > >
> > > > I'll try to do one this week, but I can't submit a patch officially
> > > > because of my employer being staunchly against signing the copyright
> > > > disclaimer.
> > >
> > > :/
> > >
> > > So please just give directions on what to modify and how, and that'd
> > > be enough for someone (probably me) to get started.
> > >
> > > Thanks!
> > >
> > > --
> > >  Bastien
> >
> >
> >
> > --
> > Yours sincerely, Vladimir Nikishkin
> >



-- 
Yours sincerely, Vladimir Nikishkin