methods and try() [R-devel]

On 8/16/07, Luke Tierney <luke at stat.uiowa.edu> wrote:

On Wed, 15 Aug 2007, Byron Ellis wrote:

Hi all, I'm having a problem with some sort of interaction with try()
and methods, I think.

The setup is as follows, I have an S4 class that holds an environment
and I would like to evaluate the right hand side of a function inside
that environment. No problem there.

However, if the formula involves a symbol that doesn't exist, which
may or may not happen, it fails as it should and reports and error
"blah blah does not exist." As it should.

When I wrap that same call in a try() statement, the error becomes "no
function to return from, jumping to top level," bypassing the try
statement and generally wreaking havoc. Any clues what might be
causing this?

Yes.  There is no context on the stack that corresponds to the
environment to which a jump is to be made.  Why that is the case is
impossible to tell without a simple reproducible example.

I have a sinking feeling that generating a good reduction will also
find my bug. :-) I was mostly wondering if there had been a recent
change in the try() machinery. In any case, I'll keep hunting for the
problem.

Best,

luke


--
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu