Re: Org src-blocks not shown correctly

[Thorsten Jolitz <tjolitz@gmail.com>]

Eric S Fraga <e.fraga@ucl.ac.uk> writes:

> On Thursday, 21 Aug 2014 at 21:09, Thorsten Jolitz wrote:
>
> [...]
>
>> hmm ... I don't even know "who" is rendering/fontifying these blocks in
>> article mode. I'm not really up-to-date with gnus, but fairly up-to-date
>> with Org - is Org at all involved here?
>
> Good questions.  I know that I used to have, a very long time ago now,
> my own customisations for viewing org snippets with fontification but
> there is no sign of any such customisations in my files any
> longer.  Gnus itself must be taking care of it.  So, from the git log of
> gnus: 
>
> ,----
> | commit 3313cd8482c0ac34077ae1ca4721bb6af8b0e0b6
> | Author: Lars Ingebrigtsen <larsi@gnus.org>
> | Date:   Sat Jan 28 20:33:23 2012 +0100
> | 
> |     Make fontification of org modes work again
> |     
> |     * mm-view.el (mm-display-inline-fontify): Bind
> | font-lock-support-mode'
> |     instead of setting it locally, since the latter doesn't seem to have
> |     any effect (most of the time).
> `----
>
> Maybe have a look at mm-view.el, specifically mm-display-inline-fontify?

Yes, this is the function doing the job:

,----[ C-h f mm-display-inline-fontify RET ]
| mm-display-inline-fontify is a Lisp function in `mm-view.el'.
| 
| (mm-display-inline-fontify HANDLE &optional MODE)
| 
| Insert HANDLE inline fontifying with MODE.
| If MODE is not set, try to find mode automatically.
`----

It looks alright to me, the only problem is that 'handle, i.e. the
org-element src-block in this case, lacks a trailing linefeed:

,----
| Result: "#+BEGIN_SRC emacs-lisp\n  (- 2 2)\n#+END_SRC\n"
`----

now we need only to find out the place where 'handle' is parsed (I could
not find it in mm-view.el in reasonable time) then we would see the
cause of the problem. 

If this uses the new parser, this is parsed:

,----[ C-h f org-element-src-block-parser RET ]
| org-element-src-block-parser is a compiled Lisp function in
| `org-element.el'.
| [...]
| Return a list whose CAR is `src-block' and CDR is a plist
| containing `:language', `:switches', `:parameters', `:begin',
| `:end', `:number-lines', `:retain-labels', `:use-labels',
| `:label-fmt', `:preserve-indent', `:value', `:post-blank' and
| `:post-affiliated' keywords.
`----

but the interpreter

,----[ C-h f org-element-src-block-interpreter RET ]
| org-element-src-block-interpreter is a compiled Lisp function in
| `org-element.el'.
| 
| (org-element-src-block-interpreter SRC-BLOCK CONTENTS)
| 
| Interpret SRC-BLOCK element as Org syntax.
| CONTENTS is nil.
`----

uses only these properties, thus the :post-blank's are lost. 

,----
| (:language :switches :parameters :value :preserve-indent)
`----

Otherwise, with old-school regexp-matching, the trailing blank
line isn't part of the match either.

-- 
cheers,
Thorsten