org-babel prepends <<noweb>> expansions with the prefix of the <<tag>>? Can this be turned off?

org-babel prepends <<noweb>> expansions with the prefix of the <<tag>>? Can this be turned off?

[Vladimir Nikishkin]

Hello, everyone

I have the following case:

#+name: test1
#+begin_src shell
LINE to comment
LINE to not comment
#+end_src

#+begin_src shell
  #<<test1>>
#+end_src

When I expand it, I get:
#LINE to comment
#LINE to not comment

That's not entirely what I want. Can this behaviour be switched off somehow?

-- 
Yours sincerely, Vladimir Nikishkin

Re: org-babel prepends <<noweb>> expansions with the prefix of the <<tag>>? Can this be turned off?

[Johannes Dahl]

Hi,

That's a fun coincidence, I ran into this behaviour a couple of days
ago as well. For anyone wondering why one would want to comment out
their noweb tags but still expect them to result in uncommented code
expansion: if one is to edit a source block containing Noweb tags, the
emacs mode for that programming language might interpret those tags in
an unexpected way and give a messy result, e.g. in my case with
LilyPond, mess up the indentation of the rest of the code block.

Luckily, Noweb tag syntax is configurable using
org-babel-noweb-wrap-start and org-babel-noweb-wrap-end. Thus, the way
I worked around this was to define, for the file containing LilyPond
code blocks, org-babel-noweb-wrap-start as "%<<", % being LilyPond's
comment symbol. But I still wonder if there is a better way.

Cheers,
Johannes

On Tue, 25 Feb 2020 at 04:10, Vladimir Nikishkin <lockywolf@gmail.com> wrote:
>
> Hello, everyone
>
> I have the following case:
>
> #+name: test1
> #+begin_src shell
> LINE to comment
> LINE to not comment
> #+end_src
>
> #+begin_src shell
>   #<<test1>>
> #+end_src
>
> When I expand it, I get:
> #LINE to comment
> #LINE to not comment
>
> That's not entirely what I want. Can this behaviour be switched off somehow?
>
> --
> Yours sincerely, Vladimir Nikishkin
>

Re: org-babel prepends <<noweb>> expansions with the prefix of the <<tag>>? Can this be turned off?

[Johannes Dahl]

Having re-read Vladimir's original question, it looks like I may have
misunderstood it at first. Now I'm wondering: What's the use case for
referencing a code block but commenting out the first line?


On Tue, 25 Feb 2020 at 09:00, Johannes Dahl <muusik@gmail.com> wrote:
>
> Hi,
>
> That's a fun coincidence, I ran into this behaviour a couple of days
> ago as well. For anyone wondering why one would want to comment out
> their noweb tags but still expect them to result in uncommented code
> expansion: if one is to edit a source block containing Noweb tags, the
> emacs mode for that programming language might interpret those tags in
> an unexpected way and give a messy result, e.g. in my case with
> LilyPond, mess up the indentation of the rest of the code block.
>
> Luckily, Noweb tag syntax is configurable using
> org-babel-noweb-wrap-start and org-babel-noweb-wrap-end. Thus, the way
> I worked around this was to define, for the file containing LilyPond
> code blocks, org-babel-noweb-wrap-start as "%<<", % being LilyPond's
> comment symbol. But I still wonder if there is a better way.
>
> Cheers,
> Johannes
>
> On Tue, 25 Feb 2020 at 04:10, Vladimir Nikishkin <lockywolf@gmail.com> wrote:
> >
> > Hello, everyone
> >
> > I have the following case:
> >
> > #+name: test1
> > #+begin_src shell
> > LINE to comment
> > LINE to not comment
> > #+end_src
> >
> > #+begin_src shell
> >   #<<test1>>
> > #+end_src
> >
> > When I expand it, I get:
> > #LINE to comment
> > #LINE to not comment
> >
> > That's not entirely what I want. Can this behaviour be switched off somehow?
> >
> > --
> > Yours sincerely, Vladimir Nikishkin
> >

Re: org-babel prepends <<noweb>> expansions with the prefix of the <<tag>>? Can this be turned off?

[Bastien]

Hi Vladimir,

Vladimir Nikishkin <lockywolf@gmail.com> writes:

> That's not entirely what I want.

What do you want instead?  It's not clear to me from your example.

Thanks,

-- 
 Bastien

Re: org-babel prepends <<noweb>> expansions with the prefix of the <<tag>>? Can this be turned off?

[Vladimir Nikishkin]

Hello, Bastien,

Thanks for getting back to me.
In ob-core.el, function org-babel-expand-noweb-references, line 2747,
there is a 'mapconcat, that is commented as ";; Interpose PREFIX
between every line."
It prepends the "prefix", that is the content of the block to be
expanded from the beginning of the line where a <<noweb>> reference is
encountered to the beginning of the reference itself, that is to the
first "<".

My point is that this is not the most obvious way to do the expansion.
It does work if the "prefix" is a line comment character, similar to C++ "//"

However, consider the following example:

```
# -*- mode: org; -*-

* test
  :PROPERTIES:
  :header-args:    :noweb yes
  :END:

#+name: block1
#+begin_src shell
printf "test1 \n"
printf "test2 \n"
printf "test3 \n"

#+end_src

#+begin_src shell :shebang "#!/bin/chibi-scheme"
#<<block1>> <<block1>>

#+end_src
```

Expanding this example gives:

```
#printf "test1 \n"
#printf "test2 \n"
#printf "test3 \n"
# printf "test1 \n"
#<<block1>> printf "test2 \n"
#<<block1>> printf "test3 \n"
#<<block1>>
```

Not a very obvious interpretation!
At least I would expect the following instead:

```
#printf "test1 \n"
printf "test2 \n"
printf "test3 \n" printf "test1 \n"
printf "test2 \n"
printf "test3 \n"
```

Because at least it wouldn't leave anything resembling a "<<noweb>>"
block in the expansion result.

Thanks for looking at this issue.

Vlad

On Mon, 7 Sep 2020 at 12:33, Bastien <bzg@gnu.org> wrote:
>
> Hi Vladimir,
>
> Vladimir Nikishkin <lockywolf@gmail.com> writes:
>
> > That's not entirely what I want.
>
> What do you want instead?  It's not clear to me from your example.
>
> Thanks,
>
> --
>  Bastien



-- 
Yours sincerely, Vladimir Nikishkin