Re: ob-calc duplicate stack-element issue

[Marco Wahl <marcowahlsoft@gmail.com>]

Heiko Schmidt <Heiko.Schmidt@webbedtables.de> writes:

> - problem: When evaluating the calc snippets the top of stack element
>    is dropped. Because every "begin/end_src calc" block drops the top
>    of stack, one can't reuse the result in following blocks.

> Number of cars (PKW) in germany:
>
> #+begin_src calc :exports both
> 45e6
> #+end_src
>
>
> #+RESULTS:
> : 45000000.
>
> Yearly mileage in [km/y]
>
> #+begin_src calc :exports both
> 15000
> #+end_src
>
>
> #+RESULTS:
> : 15000
>
> Calculate amount of complete km per year
>
> #+begin_src calc :exports both
> '*
> #+end_src
>
>
> #+RESULTS:
> : 675000000000.

> - problem: babel removes the resulting top stack element from the
>    stack
>
> - tried solution: duplicate the last stack-element on evaluation with
>    "' " (emulate <space> press to duplicate the top element of the
>    stack in calc)

> ** hope for a solution or work around from the community
>
> - preferred: Is there a way to leave the top of stack from one snippet
>    to the next (which I don't know)?
> - alternative: Is there a way to duplicate the top of stack element
>    between begin/end_src calc blocks?
> - any advice is appreciated.

Okay.  I take here the "any advice is appreciated" part.

AFAICS at the org babel calc evaluation the last value of the calc stack
gets dropped.

So your workaround is okay, I think.  You can just write any dummy
element at the bottom of each block e.g. just 0.  No need of
duplication.  Looks a bit hackish to me but so what?

Another approach could be "noweb".  Example (you would just evaluate the
block at the bottom):

--8<---------------cut here---------------start------------->8---
Number of cars (PKW) in germany:

#+name: numcars
#+begin_src calc :exports both
45e6
#+end_src

Yearly mileage in [km/y]

#+name: mileage
#+begin_src calc :exports both
15000
#+end_src

Calculate amount of complete km per year

#+begin_src calc :noweb yes
<<numcars>>
<<mileage>>
'*
#+end_src
--8<---------------cut here---------------end--------------->8---


HTH,
-- Marco