Re: source blocks DAG evaluation

["Thomas S. Dye" <tsd@tsdye.online>]

Aloha c4to,

I would be tempted to use noweb expansion here.

#+name: libB
#+begin_src scheme :results none :noweb yes
<<libA>>
(define greetings (string-append hi ", " "to all the people!"))
#+end_src

#+begin_src scheme :session example :results output :noweb yes
<<libB>>
(display greetings)
#+end_src

Does this do what you want?

All the best,
Tom

c4t0 writes:

> Hi,
>
> Is it possible to have a dependency hierarchy of source blocks?
>
> i.e.: in C, if you use libA from a compilation unit and that 
> library needs libB, you don't need to include it in main.c
>
> -> main.c
> #include "libB.h"
> -> libB.c
> #include "libA.h"
>
> you don't need to:
> -> main.c
> #include "libB.h"
> #include "libA.h"
>
> because library headers are closed under inclusion.
>
> I haven't succeeded in doing the same in org-mode. Even after 
> populating org-babel-library-of-babel.
>
> Using #+call just doesn't work. Using :var is better, evaluates 
> all, but there appears to lack session support, it doesn't check 
> for cycles and it feels a little hacky
>
> With #+call I need to do it like this:
>
> #+name: libA
> #+begin_src scheme :results none
> (define hi "hello")
> #+end_src
>
> #+name: libB
> #+begin_src scheme :results none
> (define greetings (string-append hi ", " "to all the people!"))
> #+end_src
>
> here is my "main" I need to C-c C-c in each #+call line and 
> write the :session that the code block uses in each one, and do 
> it in the correct order. If I C-c C-c in libB first it won't 
> eval because 'hi' is not defined.
>
> #+call: libB[:session example]
> #+call: libA[:session example]
> #+begin_src scheme :session example :results output
> (display greetings)
> #+end_src
>
> source blocks can be #+call(ed) but aren't closed under #+call 
> (a source block can be called but then the callee won't)
>
> instead I would like to :
>
> #+name: libA
> #+begin_src scheme :results none
> (define hi "hello")
> #+end_src
>
> #+call: libA
> #+name: libB
> #+begin_src scheme :results none
> (define greetings (string-append hi ", " "to all the people!"))
> #+end_src
>
> #+call: libB
> #+begin_src scheme :session example :results output
> (display greetings)
> #+end_src
>
> - there shouldn't be needed to C-c C-c in the #+call line, 
> evaluating the source block alone should suffice.
> - there shouldn't be a need to write the :session
>   - it should use the session of the user evaled block, unless 
>   specified otherwise
>
> In the other hand, using :var with a dummy variable:
>
> #+name: libA
> #+begin_src scheme :results none
> (define hi "hello")
> #+end_src
>
> #+name: libB
> #+begin_src scheme :results none :var _=libA
> (define greetings (string-append hi ", " "to all the people!"))
> #+end_src
>
> #+HEADER: :var _=libB
> #+begin_src scheme :session example :results output
> (display greetings)
> #+end_src
>
> It evals libA then libB and finally the (display greetings) 
> code.
> But it fails, because the :session example is ignored. Even if I 
> add a :session example to every source block (which would be 
> really bad, sessión must be decided by the consumer) it doesn't 
> work. I think that is because :var expects a value, so it just 
> opens a new session to evaluate code every time.
>
> Besides if there are any dependency cycles, it just fails with: 
> Lisp nesting exceeds ‘max-lisp-eval-depth’
>
> So if I'm right and there is not an implemented way to do this, 
> how can we do it? Adding session support for :var? constructing 
> a DAG of #+calls and then evaluating in order? maybe using a new 
> header?
>
> COD.


--
Thomas S. Dye
https://tsdye.online/tsdye