[Rd] update.formula and backticked colons

[Prof Brian Ripley]

You can always check the list archives (the ETHZ ones): it did make 
it.  See the thread starting at

https://stat.ethz.ch/pipermail/r-devel/2009-July/054184.html

I need to look more carefully, but this is not what ... is documented 
to do and it would need to be an extra argument for this method. 
Since terms.formula predates backticks, perhaps the change is better 
made there?

On Fri, 31 Jul 2009, Sundar Dorai-Raj wrote:

> On Thu, Jul 30, 2009 at 2:30 PM, Sundar Dorai-Raj<sdorairaj at gmail.com> wrote:
>> On Thu, Jul 30, 2009 at 2:28 PM, Sundar Dorai-Raj<sdorairaj at gmail.com> wrote:
>>> I just noticed the following in update.formula and I'm wondering if
>>> this behavior is the intention of the developers. Here's an example:
>>>
>>> update(`a: b` ~ x, ~ . + y)
>>>
>>> Note now that the response has no backticks and is interpreted as a:b
>>> (i.e. ":" is now an operator). This is because in update.formula the
>>> call to terms.formula uses simplify = TRUE. I'm working with data that
>>> has a lot of colons in their names and for reporting purposes I don't
>>> want to use make.names to avoid this situation. I do have a solution
>>> which simply avoids using update.formula, but I wonder if the
>>> developers would consider removing the "simplify" argument and allow
>>> it to be passed through "...", which is currently ignored by
>>> update.formula. Alternatively, add a simplify=TRUE to the
>>> update.formula call, which can manually be set to FALSE by the user.
>>>
>>> I would love to hear any comments or criticisms of my findings.
>>>
>>> Thanks,
>>>
>>> --sundar
>>>
>>
>> Forgot my version info
>>
>>> version
>>               _
>> platform       x86_64-unknown-linux-gnu
>> arch           x86_64
>> os             linux-gnu
>> system         x86_64, linux-gnu
>> status
>> major          2
>> minor          9.1
>> year           2009
>> month          06
>> day            26
>> svn rev        48839
>> language       R
>> version.string R version 2.9.1 (2009-06-26)
>>
>
> This bounced on me so I don't know if it actually made it through.
> Sorry if this is a repost.
>
> --sundar
>
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>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595