Re: Babel, Python and UTF-8

[Vincent Beffara <vbeffara@ens-lyon.fr>]

Hi,

>> (and it would be excellent to allow for a code block as a preamble,
>> instead of a string in the header or as an alternative, because
>> preambles once they are allowed tend to grow uncontrollably ;->)
>
> This is currently possible using the `sbe' function.  Arbitrary emacs
> lisp can be placed inside of header arguments, and the `sbe' take the
> name of a code block and returns its result.

Very cool ! That does all I want, thanks for the info. For multi-line it
is a bit heavy to write, with lots of \n and preamble .= "lskjd", but I
can live with that. Unless there is a way already to write something
like this ?

--8<---------------cut here---------------start------------->8---
#+source: my-preamble
#+begin_src python :return preamble
  # -*- coding: utf-8 -*-"
  import os,sys,whatever
#+end_src

#+begin_src python :preamble (org-babel-get-and-expand-source-code-body my-preamble) :return s
  s = "é"
#+end_src
--8<---------------cut here---------------end--------------->8---

There is org-babel-get-src-block-info but it looks at the block around
(point), not by name ... so I guess it would not be too hard to write
the extraction method, but it might be somewhere in the code already.

>> One naive question : why is the code path different for tangling and
>> evaluation ? One would think that a natural way for evaluation would be
>> to tangle the current block (plus included noweb stuff etc) into a
>> temporary file and eval that file ... and that would enable shebang for
>> evaluation as well. There must be something I am missing here.
>
> Tangling works for *any* programming language, even those which have yet
> to be created and have no explicit Emacs or Org-mode support, this is
> because on tangling the code block is simply treated as text.

As far as I understood from testing, tangling does adapt to the language
(at least to implement :var in a suitable way), so I was under the
impression that evaluating could be implemented as some kind of wrapping
around the tangled output - and obviously the wrapping would have to be
language-specific even if for the most part the tanglong is not.

I am just discovering all of this, sorry if I have horrible
misconceptions about the thing ...

Regards,

        /v