Re: question about chaining function calls in org-babel

From: Dan Davison <davison@stats.ox.ac.uk>
To: Inquisitive Scientist <inquisitive.scientist@gmail.com>
Cc: emacs-orgmode@gnu.org
Subject: Re: question about chaining function calls in org-babel
Date: Wed, 04 Aug 2010 22:08:36 -0400	[thread overview]
Message-ID: <87tyn9erq3.fsf@stats.ox.ac.uk> (raw)
In-Reply-To: <AANLkTin--bVLyjM_eQH+9n3MnHk5ONQCA8YV+2OS2C05@mail.gmail.com> (Inquisitive Scientist's message of "Wed, 4 Aug 2010 20:19:16 -0400")

Hi I.S.,

Inquisitive Scientist <inquisitive.scientist@gmail.com> writes:

> Dear Experts,
>
> I think org-babel is awesome but I'm having some trouble chaining
> together multiple function calls.
>
> Specifically, I would like to do something like the following
> #+tblname: fancier
> | mean   |
> |--------|
> | #ERROR |
> #+TBLFM: @2$1='(sbe "python-mean" (x (sbe "tbl-example-data" (seed 4) (size
> (sbe "square" (x 4))))))
> but it doesn't work.

OK, first off, personally I would use a dedicated src block to construct
the complex chain of calls. So your most complex example can be done with

#+tblname:
|          mean |
|---------------|
| 7.52617964952 |
#+TBLFM: @2$1='(sbe "chain")

#+srcname: chain
#+begin_src emacs-lisp :var x=python-mean(x=tbl-example-data(seed=4, size=square(x=4)))
x
#+end_src

[...]

> Try to do something even fancier and it doesn't work:
> #+tblname: fancier
> | mean |
> |------|
> |      |
> #+TBLFM: @2$1='(sbe "python-mean" (x "tbl-example-data(seed=4,size=square(4))"))

This one works if we name the argument to square:

#+tblname: fancier
|          mean |
|---------------|
| 7.52617964952 |
#+TBLFM: @2$1='(sbe "python-mean" (x "tbl-example-data(seed=4,size=square(x=4))"))

Beyond that, your examples feature one sbe nested inside another. For
example

| mean   |
|--------|
| #ERROR |
#+TBLFM: @2$1='(sbe "python-mean" (x (sbe "tbl-example-data" (seed 4) (size 16))))

I *believe* that there is no expectation for this to work, because sbe
is an elisp function (well, a macro), and not a source block. In other
words, the first sbe is expecting a source block reference, whereas what
it gets is this lisp form:

(sbe "tbl-example-data" (seed 4) (size 16))

My guess is that sbe does not undertake to evaluate a lisp form
occurring in that context. But I admit that I still find these
complicated macros more or less incomprehensible, so we could do with
Eric's input here.

As for debugging, all I know of is to place print statements inside the
macro.

The docstring says

Dan

>
> Try to do something even fancier with sbe and it doesn't work.
> #+tblname: fancier
> | mean |
> |------|
> |      |
> #+TBLFM: @2$1='(sbe "python-mean" (x (sbe "tbl-example-data" (seed 4) (size
> square(4)))))
>
> One more try:
> #+tblname: fancier
> | mean   |
> |--------|
> | #ERROR |
> #+TBLFM: @2$1='(sbe "python-mean" (x (sbe "tbl-example-data" (seed 4) (size
> (sbe "square" (x 4))))))
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