[Babel] Arguments...

[Babel] Arguments...

[Sébastien Vauban]

Hello,

Two small questions, with that minimal example:

#+begin_src org
,* Database
,
,** Back up the database
,
,Create a backup file of the existing database:
,
,#+srcname: backup-db(dbName, dbBackupFile)
,#+begin_src sql
,BACKUP DATABASE dbName TO DISK = 'dbBackupFile'
,go
,#+end_src
,
,** Back up the database
,
,Create a backup file of the existing database:
,
,#+srcname: backup-db :var dbName :var dbBackupFile
,#+begin_src sql
,BACKUP DATABASE dbName TO DISK = 'dbBackupFile'
,go
,#+end_src
#+end_src

1. I read on http://orgmode.org/manual/var.html that the second way to pass
   arguments is "more natural". Though, "nobody" "never" uses it in all the
   examples published on this ML. Why? Are there still subtle differences, or
   could such come in the future that would make one choose one over the
   other?

2. In both cases, the variables are not exported to HTML (and LaTeX?), making
   the readability of such a documented code a bit difficult. Feature or bug?

Best regards,
  Seb

-- 
Sébastien Vauban


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Re: [Babel] Arguments...

[Eric Schulte]

Sébastien Vauban <wxhgmqzgwmuf@spammotel.com> writes:

> Hello,
>
> Two small questions, with that minimal example:
>
> #+begin_src org
> ,* Database
> ,
> ,** Back up the database
> ,
> ,Create a backup file of the existing database:
> ,
> ,#+srcname: backup-db(dbName, dbBackupFile)
> ,#+begin_src sql
> ,BACKUP DATABASE dbName TO DISK = 'dbBackupFile'
> ,go
> ,#+end_src
> ,
> ,** Back up the database
> ,
> ,Create a backup file of the existing database:
> ,
> ,#+srcname: backup-db :var dbName :var dbBackupFile
> ,#+begin_src sql
> ,BACKUP DATABASE dbName TO DISK = 'dbBackupFile'
> ,go
> ,#+end_src
> #+end_src
>
> 1. I read on http://orgmode.org/manual/var.html that the second way to pass
>    arguments is "more natural". Though, "nobody" "never" uses it in all the
>    examples published on this ML. Why? Are there still subtle differences, or
>    could such come in the future that would make one choose one over the
>    other?
>

I think we are committed to maintaining both ways of defining variables
for code blocks for the foreseeable future.

>
> 2. In both cases, the variables are not exported to HTML (and LaTeX?), making
>    the readability of such a documented code a bit difficult. Feature or bug?
>

The variable names should be exported to both HTML and LaTeX (when
org-export-latex-listings is set to true) when the following declaration
schema is used (at least they are for me).

#+source: something(x=9)
#+begin_src emacs-lisp
  x
#+end_src

Best -- Eric

>
> Best regards,
>   Seb

Re: [Babel] Arguments...

[Sébastien Vauban]

Hi Eric,

"Eric Schulte" wrote:
> Sébastien Vauban <wxhgmqzgwmuf-geNee64TY+gS+FvcfC7Uqw@public.gmane.org> writes:
>> The variables are not exported to HTML (and LaTeX?), making the readability
>> of such a documented code a bit difficult. Feature or bug?
>
> The variable names should be exported to both HTML and LaTeX (when
> org-export-latex-listings is set to true) when the following declaration
> schema is used (at least they are for me).
>
> #+source: something(x=9)
> #+begin_src emacs-lisp
>   x
> #+end_src

I confirm that variable names are not exported when they don't get a value,
such as here:

#+source: add-column-in-table(table, column, type, nullability)
#+begin_src sql
-- add column `$column' (if column does not exist yet)
IF NOT EXISTS (SELECT *
               FROM INFORMATION_SCHEMA.COLUMNS
               WHERE TABLE_NAME = '$table'
               AND COLUMN_NAME = '$column')
BEGIN
    ALTER TABLE $table
    ADD $column $type $nullability
END
#+end_src

Best regards,
  Seb

-- 
Sébastien Vauban


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Re: Re: [Babel] Arguments...

[Eric Schulte]

Sébastien Vauban <wxhgmqzgwmuf@spammotel.com> writes:

> Hi Eric,
>
> "Eric Schulte" wrote:
>> Sébastien Vauban <wxhgmqzgwmuf@spammotel.com> writes:
>>> The variables are not exported to HTML (and LaTeX?), making the readability
>>> of such a documented code a bit difficult. Feature or bug?
>>
>> The variable names should be exported to both HTML and LaTeX (when
>> org-export-latex-listings is set to true) when the following declaration
>> schema is used (at least they are for me).
>>
>> #+source: something(x=9)
>> #+begin_src emacs-lisp
>>   x
>> #+end_src
>
> I confirm that variable names are not exported when they don't get a value,
> such as here:
>
> #+source: add-column-in-table(table, column, type, nullability)
> #+begin_src sql
> -- add column `$column' (if column does not exist yet)
> IF NOT EXISTS (SELECT *
>                FROM INFORMATION_SCHEMA.COLUMNS
>                WHERE TABLE_NAME = '$table'
>                AND COLUMN_NAME = '$column')
> BEGIN
>     ALTER TABLE $table
>     ADD $column $type $nullability
> END
> #+end_src
>

Ah, That is the problem.

Babel currently only support variable names *with* default values.  This
simplifies our internal variable handling.  I agree that in the future
it would be good to allow variable names which don't have default values
specified but currently all behavior is undefined when variables
definitions don't have an assignment.

I'm noting this with our variable-handling related development tasks.

Best -- Eric