Re: [BABEL] BUG Re: Omitting try/catch blocks from tangled R code?

[Eric Schulte <schulte.eric@gmail.com>]

John Hendy <jw.hendy@gmail.com> writes:

> On Mon, Mar 17, 2014 at 10:00 AM, Eric Schulte <schulte.eric@gmail.com> wrote:
>> John Hendy <jw.hendy@gmail.com> writes:
>>
>>> On Fri, Feb 7, 2014 at 1:22 PM, Rainer M Krug <Rainer@krugs.de> wrote:
>>>>
>>>>
>>>>
>>>> On 02/07/14, 17:47 , Eric Schulte wrote:
>>>> > Rainer M Krug <Rainer@krugs.de> writes:
>>>> >
>>>> >> On 02/07/14, 07:18 , John Hendy wrote:
>>>> >>> Greetings,
>>>> >>>
>>>> >>>
>>>> >>> I don't usually tangle, but am creating a code file to go along with a
>>>> >>> presentation I'm giving this weekend so that attendees can try things
>>>> >>> out afterward by cloning my github repo where all the data and
>>>> >>> necessary files are stored.
>>>> >>>
>>>> >>> In my presentation (Beamer), I create plots via the R pdf() device,
>>>> >>> and noticed that all of the tangled code where plots are generated
>>>> >>> contains the following:
>>>> >>>
>>>> >>> pdf(file="file.pdf"); tryCatch({
>>>> >>>
>>>> >>>   code block contents here
>>>> >>>
>>>> >>> },error=function(e){plot(x=-1:1, y=-1:1, type='n', xlab='', ylab='',
>>>> >>> axes=FALSE); text(x=0, y=0, labels=e$message, col='red');
>>>> >>> paste('ERROR', e$message, sep=' : ')}); dev.off()
>>>> >>>
>>>> >>> Is there a way to omit this?
>>>> >>
>>>> >> This is a bug which must have been introduced some time ago - in the
>>>> >> stock version of emacs (Org-mode version 7.9.3f
>>>> >> (release_7.9.3f-17-g7524ef @
>>>> >> /usr/local/Cellar/emacs/24.3/share/emacs/24.3/lisp/org/)) it does not
>>>> >> tangle the enclosing commands to create graphics, but in 8.2 it does (I
>>>> >> don't have an older version at hand to go further back).
>>>> >>
>>>> >
>>>> > I believe this was introduced by your commit eaa3a761d.  Reversion of
>>>> > which with the following should provide a temporary workaround.
>>>>
>>
>> I take this back, the behavior is unrelated to Rainer's commit adding
>> try/catch blocks to R graphics creation logic.
>>
>> In fact I don't believe this is a bug, rather the default behavior is to
>> expand code block bodies on tangling.  This behavior may be changed by
>> using the :no-expand header argument which will inhibit code block body
>> expansion during tangling.
>>
>
> Got it, and thanks for the new variable tip!
>
> Out of curiosity, is there a consensus that this is the preferred
> behavior for tangling by default?

There may have been a consensus in a single thread motivated by a single
use case, which should not necessarily be a global consensus.

> I'm guessing at some point it was decided that the need was preferred
> to have these bits inserted before/after code blocks, but just trying
> to confirm this. It seems odd to me, at least given R's behavior, that
> someone would prefer these bits to show up in the tangled file since
> they appeared to serve the purpose of having Org not fail during
> export vs. benefitting the code in any way (if I wasn't running code
> through R, I'd just get the errors directly).
>

I'd be happy to add :no-expand to the default R header arguments.  Or
even to change this behavior globally, if the current behavior is
universally surprising.

Best,

>
>
> John
>
>> Best,
>>
>> --
>> Eric Schulte
>> https://cs.unm.edu/~eschulte
>> PGP: 0x614CA05D

-- 
Eric Schulte
https://cs.unm.edu/~eschulte
PGP: 0x614CA05D