R devel - Oct 2005 - model.response() as a generic function?

Dear R contributors, 
  Gary King, Olivia Lau (both at Harvard) and I are working on an R
package where we are trying to write functions equivalent to
model.frame(), model.matrix(), and model.response() for multiple equations
models (i.e., models that require the specification of multiple formulae).  
However, we noticed that while model.frame() and model.matrix() are
generic functions, model.response() is not. It would be nice if
model.response() is also a generic function so that we can make use of the
same function name for a large class of models we are working on. Is there
any possibility that this change can be made in the future version of R?
Thank you very much for your consideration in advance,
Kosuke

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Kosuke Imai               Office: Corwin Hall 041
Assistant Professor       Phone: 609-258-6601 
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There is a considerable difference: model.response is documented to work 
on a model frame.  Why does model.response(model.frame(object))) not work 
in the generality you need?

Please give us some examples of why you are trying to do, and how you 
would envisage a generic model.response being documented.  (It is 
currently documented as equivalent to model.extract(,"response").)

On Fri, 28 Oct 2005, Kosuke Imai wrote:
> Dear R contributors,
>  Gary King, Olivia Lau (both at Harvard) and I are working on an R
> package where we are trying to write functions equivalent to
> model.frame(), model.matrix(), and model.response() for multiple equations
> models (i.e., models that require the specification of multiple formulae).
> However, we noticed that while model.frame() and model.matrix() are
> generic functions, model.response() is not. It would be nice if
> model.response() is also a generic function so that we can make use of the
> same function name for a large class of models we are working on. Is there
> any possibility that this change can be made in the future version of R?
> Thank you very much for your consideration in advance,
> Kosuke
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
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