From ripley at stats.ox.ac.uk  Wed Jan 30 15:27:55 2008
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Wed, 30 Jan 2008 14:27:55 +0000 (GMT)
Subject: [Rd] A "safe" do.call
In-Reply-To: <f8e6ff050801300548m1bbe36dcl72bab45872bc8416@mail.gmail.com>
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	<f8e6ff050801281830m3a46e884j715611fed13cf3a8@mail.gmail.com>
	<alpine.LFD.1.00.0801290525250.23305@gannet.stats.ox.ac.uk>
	<f8e6ff050801290726u6d07dd3fy4a476aa89e958094@mail.gmail.com>
	<18336.21619.915655.397877@stat.math.ethz.ch>
	<f8e6ff050801300548m1bbe36dcl72bab45872bc8416@mail.gmail.com>
Message-ID: <alpine.LFD.1.00.0801301421380.28684@gannet.stats.ox.ac.uk>

This is a 'White Book' function, not really ours to re-design.
(Although the glm help page in the White Book's description of '...' never 
was correct of any S-PLUS that I used, and doesn't make a great deal of 
sense.)

I never really saw the point of glm.control(), but it might have allowed 
for future expansion that never happened.

On Wed, 30 Jan 2008, hadley wickham wrote:

>>     hw> That seems a perfectly good reason not to use ... - but
>>     hw> if you are going to use ... it seems like you shouldn't
>>     hw> warn on mismatched argument names.
>>
>> I disagree.
>>
>> One "famous" example on this was -- in S-plus, early 1990s --
>> known about S users back then, and it happened here (as well),
>> not in theory: a scientist who later came for consulting to us
>> did a logistic regression
>>
>>   mod1 <- glm(y ~ x1 + x2 + ....,  .......
>>               data = ....., famliy = binomial)
>>   summary(mod1)
>>   ...
>>
>> and was wondering about the logistic regression coefficients and
>> their interpretation and more things
>> until we found out the small typo above
>> which made glm() compute a ("gaussian") model even though the
>> user had clearly said he wanted a logistic one.
>>
>> Can you see the point?
>
> The point is that glm shouldn't use ... but should explicitly list all
> of the arguments that it takes?  Why does glm need to use ... in your
> example?
>
> If you know the set of possible arguments in advance, why not list
> them explicitly and document them individually, and not use ... at
> all?
>
> Hadley
>
> --
> http://had.co.nz/
>

-- 
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



[Rd] A "safe" do.call
Prof Brian Ripley