Re: Capture template and elisp expression

From: Rainer M Krug <r.m.krug@gmail.com>
To: Carsten Dominik <carsten.dominik@gmail.com>
Cc: nicholas.dokos@hp.com, emacs-orgmode <emacs-orgmode@gnu.org>
Subject: Re: Capture template and elisp expression
Date: Fri, 07 Jan 2011 09:22:28 +0100	[thread overview]
Message-ID: <4D26CD44.1070604@gmail.com> (raw)
In-Reply-To: <FBA98CDC-6138-4EF2-B9F5-57F01A31620A@gmail.com>

On 01/06/2011 11:44 PM, Carsten Dominik wrote:
> 
> On Jan 6, 2011, at 11:26 PM, Nick Dokos wrote:
> 
>> Rainer M Krug <r.m.krug@gmail.com> wrote:
>>
>>>
>>> Hi
>>>
>>> I want to use a Capture Template to record changes to files under
>>> version control. Everything works as expected, but I would like to
>>> include the current revision in the template.
>>>
>>> Therefore I tried the following:
>>>
>>> * %T %? at %a by Rainer M Krug, email: Rainer@krugs.de
>>> %(vc-working-revision buffer-file-name)
>>>
>>> for the template, but I get an error:
>>>
>>> **** <2011-01-06 Thu 13:06>  at
>>> [[file:~/Documents/Projects/BiocontrolAndAlienDynamics/nonSpatialAcacia/trunc/R/nsa.org::*Finalise][Finalise]]
>>>
>>> by Rainer M Krug, email: Rainer@krugs.de %![Error: (wrong-type-argument
>>> stringp nil)]
>>>
>>> Any idea how I could get the revision of the org file from which the
>>> Capture has been initiated (here
>>> ~/Documents/Projects/BiocontrolAndAlienDynamics/nonSpatialAcacia/trunc/R/nsa.org
>>>
>>> )?
>>>
>>
>> There are a few problems: the evaluation of the sexp happens in the
>> capture buffer where buffer-file-name returns nil. Even if you could
>> get the file name, vc-working-revision would return nil on a file that
>> is not VC-registered and the template would barf.
>>
>> Those are easy problems to solve but there is another one that seems
>> insurmountable (with current code): my original thought was to use the
>> %a escape to pass the link to a lisp function, extract the file name
>> from it[fn:1] and run vc-working-revision on it (with appropriate
>> safeguards
>> to catch non-VC files), something like this:
>>
>> "* %T %? at %a by Rainer M Krug, email: Rainer@krugs.de       
>> %(rk-custom-function-to-get-vc-revision \"%a\")"
>>
>> However, this fails because at the time that %(sexp) constructs are
>> expanded, simple %a etc. constructs have not been expanded yet, so what
>> the function above gets is a literal "%a": the subtitution sequence is
>>
>>            ;; %[] Insert contents of a file.
>>
>>            ...
>>
>>            ;; %() embedded elisp
>>
>>            ...
>>
>>            ;; Simple %-escapes
>>
>> (see lisp/org-capture.el, lines 1181-1229 or so).
>>
>> Moreover, this sequence was different and was changed deliberately (see
>> the thread http://thread.gmane.org/gmane.emacs.orgmode/27649), so if it
>> is changed back, Sebastion Rose will not be happy :-)
>>
>> So it seems there is no way to pass values from the capture context to a
>> lisp function in the capture template, but maybe I'm missing something.
>>
>> Thanks,
>> Nick
>>
>> Footnotes:
>> [fn:1] Is there an easier way to get the filename of the file I was
>> visiting when I initiated the capture? If not, should there be? Perhaps
>> a %f escape?
> 
> Hi Nick,

Hi Carsten,

> 
> you can use
> 
>     (buffer-file-name (org-capture-get :original-buffer))

This works perfectly - thanks a million. For the record: I use

%(vc-working-revision (buffer-file-name (org-capture-get :original-buffer)))

to get the vc revision number.
But now I thought - OK - now I can add the state of the file, returned
by vc-state (this is working i a nother document in the org-document).
So I added:

%(vc-state (buffer-file-name (org-capture-get :original-buffer)))

but I get the error

Capture abort: (wrong-type-argument char-or-string-p edited)

It seems, that vc-state (which should be "up-to-date" or "edited") does
return a different type then vc-working-revision ? Can I convert
vc-state, so that it works?

> 
> and we could certainly introduce a special escape for it if helpful.

as this is a basic info, I think it would be useful to have a special
escape for this.

> 
> If it is easier, we can also put the filename itself into the property
> list,
> and any other information we like.  This should happen in the function
> org-capture,
> close to the location where the buffer is stored, so near this line:
> 
>     (org-capture-put :original-buffer orig-buf :annotation annotation
>              :initial initial)
> 
> org-capture uses this property list precisely so that it is simple
> to add any information required.

In addition to above, it should also be in the properties, oncluding
with other information, like e.g. path.

> 
> Note that, after the template has been filled in, it is better
> to access information in the property list with
> 
> 
>   (org-capture-get PROPERTY 'local)
> 
> to avoid conflicts with other ongoing capture processes.

Does this affect me for my template, or does it concern the
implementation of the buffer name as a property (above)? Because if it
does affect my template, I should ask for clarification, because I don't
understand what you mean here.

> 
> Hope this helps.

This definitely helps,

Thanks a lot,
Cheers,

Rainer

> 
> - Carsten
> 
> 
> 
> 
> 
> 
>>
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> 

-- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
Biology, UCT), Dipl. Phys. (Germany)

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