Re: [O] [PATCH] * lisp/ob-core.el (org-babel-execute-src-block): insert hash for silent results

[Sebastien Vauban]

Achim, Eric,

Achim Gratz wrote:
> Eric Schulte writes:
>> A hash marks a *result* with an indication of what was used to generate
>> it (code block & parameters).  The point of a hash is to allow the
>> result to be returned without having to re-execute.  For this reason, I
>> think that the hash should live with the result.
>
> Here Babel is assuming a very specific execution model, namely a
> functional one (a function with the same parameters always delivers the
> same results, so if you see the same function invoked with the same
> parameters you can just substitute the result from an earlier
> invocation).  Babel isn't a functional language however, so it is both
> possible and done in practice to use it for side-effects or even
> side-effects only.
>
> But back to my earlier remark about the hash value actually being a
> signature of the source block and not the result.  If I use noweb
> references, the reference text is cached, not its expansion.

Well seen... I wouldn't have thought of that...

A more general question: shouldn't cache be unusable (generate an error) when
there is a session?  In the presence of a session, I've the impression that
caching results is always wrong. Who knows its contents before executing the
code, in the next Emacs session?

Best regards,
  Seb

-- 
Sebastien Vauban