Re: [O] [BUG] R src blocks untabify literal constant TABs

[Charles C. Berry]

On Wed, 7 Oct 2015, Nicolas Goaziou wrote:

> Hello,
>
> "Charles C. Berry" <address@hidden> writes:
>
> > Attached is a patch.
>
> Thank you.
>
> > I think it is an improvement, but `org-src-preserve-indentation'
> > behaves differently according to context, which makes it hard to
> > document succinctly.
>
> There's something suspicious here.
>
> This variable is supposed to only replace tab characters used in
> indentation, not anywhere else. However, it seems that your
> documentation patch suggests otherwise. It may be a bug then.

More than one bug, I am afraid.

> Do you have any such example?

Sure, make sure that the whitespace in the `> <' below is a TAB
character (C-q C-i). Running the src block replaces the TAB when
`org-src-preserve-indentation' is nil.

Also, use `org-edit-src-code' with point in the block and immediately exist,
i.e. =C-c ' C-c '=, and the embedded tab disappears.

#+BEGIN_SRC emacs-lisp
  "this is a TAB-->     <--"
  #+END_SRC

`untabify' is called by some functions that honor (in some way)
`org-src-preserve-indentation' which explains some of this. FWIW, here
is a summary of functions that use the variable:


|---------------------------------------+-----------------------+---------------------------|
| function                              | protect-leading space | effect on 
tabs            |
|---------------------------------------+-----------------------+---------------------------|
| org-babel-exp-process-buffer          | yes or no             | ignore (+/- 
to indent)    |
| org-export-unravel-code               | yes or no             | ignore        
            |
| org-element-src-block-interpreter     | contents only or not  | ignore        
            |
| org-element-example-block-interpreter | contents only or not  | ignore        
            |
| org-fixup-indentation                 | contents only or not  | ignore (+/- 
to indent)    |
| org-babel-parse-src-block-match       | yes or no             | keep or 
remove            |
| org-babel-haskell-export-to-lhs       | yes or no             | keep or 
remove            |
| org-babel-spec-to-string              | yes or no             | keep or 
remove lead+trail |
| org-src--edit-element                 | yes or no             | keep or 
remove            |
| org-edit-src-code                     | yes or no             | keep or 
remove            |
|---------------------------------------+-----------------------+---------------------------|

the '(+/- to indent)' means that leading tabs may be added or removed
with org-metaright and friends. `keep or remove lead+trail' == "keep
or remove leading or trailing TABs only". 'contents only or not' means
there is no effect on `#+BEGIN...' etc.

HTH,

Chuck