Re: [PATCH] Allow tangling to a list of files

[Jacopo De Simoi <wilderjds@protonmail.com>]

On Tuesday, July 6, 2021 11:27:18 PM EDT Vladimir Lomov wrote:
> Hello Jacopo.
>
> ** Jacopo De Simoi <wilderjds@protonmail.com> [2021-07-06 11:24:40 -0400]:
> > Dear Vladimir,
> >
> >  thanks for your reply.
> >
> > Let me show you two examples; they are both WIP and incomplete, but you'll
> > get the gist.
> >
> > - Example 1
> >
> > https://gist.github.com/85c9b9c9ab151c5fd35bd761ef6ef569
> >
> > This is my literate config for .zshrc; as you can see different blocks are
> > tangled to different set of files; hence the output files differ (as some
> > blocks are present and other are not)
>
> I couldn't find in Org manual how tangling should work if there are several
> source code blocks with the same file name for ':tangle'. The Org manual
> section "15.8 Extracting Source Code" is a bit obscure. There are these two
> sentences
>
>   When Org tangles code blocks, it expands, merges, and transforms
>   them.  Then Org recomposes them into one or more separate files, as
>   configured through the options.
>
> The second sentence assumes that it might be possible to tangle to more than
> one file but possible options for ':tangle' don't give certain answer:
>
>   yes’
>
>        Export the code block to source file.  The file name for the source
>        file is derived from the name of the Org file, and the file extension
> is derived from the source code language identifier.
>        Example: ‘:tangle yes’.
>
>   FILENAME
>
>        Export the code block to source file whose file name is derived from
>        any string passed to the ‘tangle’ header argument.  Org derives the
>        file name as being relative to the directory of the Org file’s
>        location.  Example: ‘:tangle FILENAME’.
>
> If I understand first choice correctly then the only source block ("the code
> block") will be tangled (exported) to a source file. What Org will do if
> there are several source blocks? Concatenate them or write to a file only
> last one? (I didn't test that).
>
> The same applies to 'FILENAME' case: what Org will do if there are several
> source code blocks with the same 'FILENAME' for ':tangle'.
>
> I would say that you use here undocumented feature and you workflow could be
> broken if in some future Org version developers decide to implement only
> documented features.

I am quite sure that if more than one blocks are tangled to the same file, then
the blocks must be concatenated.  There is at least one test in the test suite
which is designed to check precisely this behavior.

>
> > - Example 2
> >
> > https://gist.github.com/2bce5d6df3f04c934fb4beda0c6560ad
> >
> > This is my literate config for xkb maps; I have several keyboards, and
> > some of them require slightly different maps.
> >
> > Once again, likely all this can be accomplished by some noweb magic, but I
> > find my approach much less intrusive (particularly the initial bit in the
> > .zshrc, which I am still refactoring, where the list of tangle targets is
> > inferred from the headline tags)
>
> I found you way of doing things a bit strange. As I already told I use
> 'noweb' feature a lot. I won't advise you to use it or not to use it but I
> find it very powerful.
>
> > Thanks again for your comments. I'd really like to see how to do the same
> > with noweb and compare my approach with the "standard" one. Once more, I
> > hope these examples clarify my point of view.
>

Thanks, I will certainly have a good look.

> If you don't distract by foreign language (Russian) you could look how I use
> 'noweb' feature for scripts (one example):
>
> https://git.sr.ht/~vp1981/scripts/tree/master/item/docs/scripts/misc.org
>
> for shell configurations:
>
> https://git.sr.ht/~vp1981/scripts/tree/master/item/docs/shell/bash.org
>
> and for Emacs configuration:
>
> https://git.sr.ht/~vp1981/scripts/tree/master/item/docs/emacs/emacs.org
>
> > Best
> >
> >  Jacopo
>
> [...]
>
> ---
> WBR, Vladimir Lomov