From luke at stat.uiowa.edu  Tue Apr  1 17:22:43 2003
From: luke at stat.uiowa.edu (Luke Tierney)
Date: Wed Apr  2 00:23:02 2003
Subject: [Rd] setGeneric
In-Reply-To: <3E89A0EE.4036A4C5@research.bell-labs.com>
Message-ID: <Pine.LNX.4.44.0304011619150.3296-100000@nokomis2.stat.umn.edu>

On Tue, 1 Apr 2003, John Chambers wrote:

> I think this is a consequence of the extra context added to make methods
> work right with R lexical scoping, namespaces, etc.  Or a subtlety in
> R's definition of missing()?
> 
> The problem is that somehow the default expression for argument `ncol'
> makes that argument appear NOT to be missing.  But an attempt to
> evaluate it fails because the local variable `n' hasn't been defined
> yet.
> 
> The following debugging snippets, using trace on the method for
> "numeric", show what's happening.  But as to why, we need some expert
> help! (Luke?)

We need a bit more info transferred across from the generic and we
need to reset the environments of the promises for missing arguments.
I'll look into it.

luke

-- 
Luke Tierney
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
   Actuarial Science
241 Schaeffer Hall                  email:      luke@stat.uiowa.edu
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[Rd] setGeneric
Luke Tierney