[R] Scoped options setting?

[Thomas Lumley]

On Wed, 16 May 2007, Zack Weinberg wrote:

> Is there any way to set options during the evaluation of a particular
> expression, with them automatically reset when control leaves that
> expression, however that happens?  Kind of like "let" on a "special"
> variable does in Lisp.  I naively tried
>

You could write with_options() as

with_options <-function(optionlist, expr){
        oldoptions<-options(optionlist)
        on.exit(options(oldoptions))
        eval(substitute(expr), parent.frame())
}

and then do
   with_options(list(warn=-1),  whatever)

 	-thomas