Re: [O] #+header: :post -> Symbol's value as variable is void: *this*

[Thorsten Jolitz]

Aaron Ecay <address@hidden> writes:

Hi Aaron,

> 2014ko uztailak 27an, Thorsten Jolitz-ek idatzi zuen:
>> 
>> Thorsten Jolitz <address@hidden> writes:
>> 
>>> Hi List, 
>>> 
>>> whats wrong with this :post header arg:
>>> 
>>> #+header: :post (format "#+attr_latex :float :placement
>>> {c}{scale=.6}\n%s" *this*)
>>> #+begin_src emacs-lisp 
>>> (+ 2 2)
>>> #+end_src
>>> 
>>> When I understand 
>>> 
>>> ,----
>>> | http://orgmode.org/manual/post.html
>>> `----
>>> 
>>> correctly, *this* should hold the block results, but I get 
>>> 
>>> ,----
>>> | Symbol's value as variable is void: *this*
>>> `----
>> 
>> 
>> This works:
>> 
>> #+name: myconcat
>> #+header: :var x=""
>> #+begin_src emacs-lisp
>>  (format "Do %sx then quit" x)
>> #+end_src
>> 
>> 
>> #+header: :post myconcat(x=*this*)
>> #+begin_src emacs-lisp 
>>  (+ 2 2)
>> #+end_src
>> 
>> #+results:
>> : Do 4x then quit
>> 
>> 
>> but how do I interpret the following sentence from the manual:
>> 
>> ,----
>> | This variable [*this*] may then be included in header argument forms
>> | such as those used in var header argument specifications allowing
>> | passing of results to other code blocks, or direct execution via Emacs
>> | Lisp.
>> `----
>> 
>> What is meant by 'direct execution via Emacs Lisp' here? I think the
>> above construct with two src-blocks is a bit heavy for the rather small
>> task and hoped I could just give an Emacs Lisp expression containing
>> *this* as value to the :post header arg, but apparently not?
>> 
>> #+header: :post (format "Do %sx then quit" *this*)
>> #+begin_src emacs-lisp 
>>  (+ 2 2)
>> #+end_src
>> 
>> -> eval: Symbol's value as variable is void: *this*
>
> The value of :post should be a babel call (in the same format as e.g. a
> #+call line), not an elisp form.  If babel sees something that looks
> like elisp, it will attempt to ‘eval’ it when parsing the src block,
> before *this* is bound (which happens only upon execution, after
> parsing).

Thats 

 #+CALL: <name>(<arguments>)

then, and looks like the headerline of the working example above:

#+header: :post myconcat(x=*this*)

Then there is no way to achieve what I had in mind. Thx. 

-- 
cheers,
Thorsten