Re: [Rd] combine UserDefinedDatabase and regular environments

From: Michael Lawrence <lawremi_at_gmail.com>
Date: Thu, 19 Nov 2009 09:14:24 -0800

On Thu, Nov 5, 2009 at 9:58 AM, Romain Francois <romain.francois_at_dbmail.com>wrote:

> Hello,
>
> Is it possible to have the effect of UserDefinedDatabase outside of
> "attached" environments ? Can I disguise an environment of the sys.frames()
> as a UserDefinedDatabase ?
>
> This seems to suggest that it might be possible :
>
> > f <- function(){ e <- environment(); class(e) <- "UserDefinedDatabase";
> ff }
> > f()
>
>
The UserDefinedDatabase support expects an R_ObjectTable C structure embedded within an externalptr as the HASHTAB of the environment. So it's
really only possible from C.

> *** caught segfault ***
> address (nil), cause 'unknown'
>
> Traceback:
> 1: f()
>
> Possible actions:
> 1: abort (with core dump, if enabled)
> 2: normal R exit
> 3: exit R without saving workspace
> 4: exit R saving workspace
>
>
> At the moment, it seems to be either lookup using UserDefinedDatabase or
> regular lookup. Has anyone tried to combine both ?
>
>
> --
> Romain Francois
> Professional R Enthusiast
> +33(0) 6 28 91 30 30
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https://stat.ethz.ch/mailman/listinfo/r-devel Received on Thu 19 Nov 2009 - 17:17:31 GMT

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