From luke at stat.uiowa.edu  Thu Aug 16 14:47:44 2007
From: luke at stat.uiowa.edu (Luke Tierney)
Date: Thu, 16 Aug 2007 07:47:44 -0500 (CDT)
Subject: [Rd] methods and try() [R-devel]
In-Reply-To: <7098abec0708152232s6d9fbb2ewb76cfa2cd4d7b1b2@mail.gmail.com>
References: <7098abec0708152232s6d9fbb2ewb76cfa2cd4d7b1b2@mail.gmail.com>
Message-ID: <Pine.LNX.4.64.0708160742020.2550@itasca2.wildberry.org>

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.

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



[Rd] methods and try() [R-devel]
Luke Tierney