Passing values by reference to src-blocks

Passing values by reference to src-blocks

[Thorsten Jolitz]

Hi List, 

this does not work, although I would think it should (at least if there
is no typo or so):

,----
| #+name: project-root
| #+header: :var buf-file=(buffer-file-name)
| #+begin_src emacs-lisp
| (file-name-directory
|  (directory-file-name
|   (file-name-directory buf-file)))
| #+end_src
`----

#+results: project-root
: /home/tj/News/drafts/

,----
| #+name: project-name
| #+header: :exports none
| #+header: :var root-dir=project-root(buf-file=(buffer-file-name))
| #+begin_src emacs-lisp
|   (mapconcat
|    'capitalize
|    (split-string
|     (file-name-nondirectory root-dir)
|     "-" 'OMIT-NULLS)
|    " ")
| #+end_src
`----

#+results: project-name

Wrong usage of :var or limitations of header arguments?

-- 
cheers,
Thorsten

Re: Passing values by reference to src-blocks

[Eric Schulte]

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Thorsten Jolitz <tjolitz@gmail.com> writes:

> Hi List, 
>
> this does not work, although I would think it should (at least if there
> is no typo or so):
>

I think everything is doing what it is supposed to from an Org-mode
perspective, see below (with different functions).


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#+name: plus-foo
#+header: :var buf-file=(buffer-file-name)
#+begin_src emacs-lisp
(concat buf-file "+foo")
#+end_src

#+RESULTS: plus-foo
: /tmp/example.org+foo

#+name: project-name
#+header: :exports none
#+header: :var root-dir=plus-foo(buf-file=(buffer-file-name))
#+begin_src emacs-lisp
(concat root-dir "+bar")
#+end_src

#+RESULTS: project-name
: /tmp/example.org+foo+bar

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>
> ,----
> | #+name: project-root
> | #+header: :var buf-file=(buffer-file-name)
> | #+begin_src emacs-lisp
> | (file-name-directory
> |  (directory-file-name
> |   (file-name-directory buf-file)))
> | #+end_src
> `----
>
> #+results: project-root
> : /home/tj/News/drafts/
>
> ,----
> | #+name: project-name
> | #+header: :exports none
> | #+header: :var root-dir=project-root(buf-file=(buffer-file-name))
> | #+begin_src emacs-lisp
> |   (mapconcat
> |    'capitalize
> |    (split-string
> |     (file-name-nondirectory root-dir)
> |     "-" 'OMIT-NULLS)
> |    " ")
> | #+end_src
> `----
>
> #+results: project-name
>
> Wrong usage of :var or limitations of header arguments?

This is to be expected.  The two blocks above compose to something like

    #+begin_src emacs-lisp
      (file-name-nondirectory
       (file-name-directory
        (directory-file-name
         (file-name-directory
          (buffer-file-name)))))
    #+end_src

Calling `file-name-nondirectory' on the results of `file-name-directory'
seems like it should give you an empty string.

Best,

-- 
Eric Schulte
https://cs.unm.edu/~eschulte
PGP: 0x614CA05D (see https://u.fsf.org/yw)

Re: Passing values by reference to src-blocks

[Thorsten Jolitz]

Eric Schulte <schulte.eric@gmail.com> writes:

>> Wrong usage of :var or limitations of header arguments?
>
> This is to be expected.  The two blocks above compose to something like
>
>     #+begin_src emacs-lisp
>       (file-name-nondirectory
>        (file-name-directory
>         (directory-file-name
>          (file-name-directory
>           (buffer-file-name)))))
>     #+end_src
>
> Calling `file-name-nondirectory' on the results of `file-name-directory'
> seems like it should give you an empty string.

Yes, I figured that out myself before I saw your post, there was a
mistake in my code. 

Thanks anyway. 

-- 
cheers,
Thorsten

Re: Passing values by reference to src-blocks

[Thorsten Jolitz]

Thorsten Jolitz <tjolitz@gmail.com> writes:

> Hi List, 
>
> this does not work, although I would think it should (at least if there
> is no typo or so):
>
> ,----
> | #+name: project-root
> | #+header: :var buf-file=(buffer-file-name)
> | #+begin_src emacs-lisp
> | (file-name-directory
> |  (directory-file-name
> |   (file-name-directory buf-file)))
> | #+end_src
> `----
>
> #+results: project-root
> : /home/tj/News/drafts/
>
> ,----
> | #+name: project-name
> | #+header: :exports none
> | #+header: :var root-dir=project-root(buf-file=(buffer-file-name))
> | #+begin_src emacs-lisp
> |   (mapconcat
> |    'capitalize
> |    (split-string
> |     (file-name-nondirectory root-dir)
> |     "-" 'OMIT-NULLS)
> |    " ")
> | #+end_src
> `----
>
> #+results: project-name
>
> Wrong usage of :var or limitations of header arguments?

This works

,----
| #+name: project-root
| #+header: :var buf-file=(buffer-file-name)
| #+begin_src emacs-lisp
| (file-name-directory
|  (directory-file-name
|   (file-name-directory buf-file)))
| #+end_src
| 
| #+name: project-name
| #+header: :exports none
| #+header: :var root=project-root
| #+begin_src emacs-lisp
|   (mapconcat
|    'capitalize
|    (split-string
|     (file-name-nondirectory
|     (directory-file-name root))
|     "-" 'OMIT-NULLS)
|    " ")
| #+end_src
`----

so it was just wrong usage ... sorry for the noise

-- 
cheers,
Thorsten