R devel - May 2012 - how to remove the 'promise' attribute of an R object (.Random.seed)?

Hi,

The problem arises when I lazyLoad() the .Random.seed from a
previously saved database. To simplify the process of reproducing the
problem, see the example below:

## this assignment may not really make sense, but illustrates the problem
delayedAssign('.Random.seed', 1L)

typeof(.Random.seed)
# [1] "integer"

rnorm(1)
# Error in rnorm(1) :
#  .Random.seed is not an integer vector but of type 'promise'

typeof(.Random.seed)
# [1] "integer"

So there must be an "attribute" "promise" somewhere attached
to
.Random.seed, and I cannot find it. The R function typeof() does not
reveal it, but the TYPEOF() function in src/main/RNG.c says it is a
'promise'.

My question is, how to make R use the real value of .Random.seed
instead of complaining about the promise? Thanks!

Regards,
Yihui
--
Yihui Xie <xieyihui at gmail.com>
Phone: 515-294-2465 Web: http://yihui.name
Department of Statistics, Iowa State University
2215 Snedecor Hall, Ames, IA

On Tue, 22 May 2012, Yihui Xie wrote:
> Hi,
>
> The problem arises when I lazyLoad() the .Random.seed from a
> previously saved database. To simplify the process of reproducing the
> problem, see the example below:
>
> ## this assignment may not really make sense, but illustrates the problem
> delayedAssign('.Random.seed', 1L)
>
> typeof(.Random.seed)
> # [1] "integer"
>
> rnorm(1)
> # Error in rnorm(1) :
> #  .Random.seed is not an integer vector but of type 'promise'
>
> typeof(.Random.seed)
> # [1] "integer"
>
> So there must be an "attribute" "promise" somewhere
attached to
> .Random.seed, and I cannot find it. The R function typeof() does not
> reveal it, but the TYPEOF() function in src/main/RNG.c says it is a
> 'promise'.
>
> My question is, how to make R use the real value of .Random.seed
> instead of complaining about the promise? Thanks!
Siple answer: Don't creat the promise in the first place, i.e. don't
use delayedAssign.

What is the real context where this arises? Knowing that may help us
decide whether the internals should address this possibility.

Best,

luke
>
> Regards,
> Yihui
> --
> Yihui Xie <xieyihui at gmail.com>
> Phone: 515-294-2465 Web: http://yihui.name
> Department of Statistics, Iowa State University
> 2215 Snedecor Hall, Ames, IA
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
-- 
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-tierney at uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu

On 12-05-22 12:22 PM, Yihui Xie wrote:
> Hi,
>
> The problem arises when I lazyLoad() the .Random.seed from a
> previously saved database. To simplify the process of reproducing the
> problem, see the example below:
>
> ## this assignment may not really make sense, but illustrates the problem
> delayedAssign('.Random.seed', 1L)
>
> typeof(.Random.seed)
> # [1] "integer"
>
> rnorm(1)
> # Error in rnorm(1) :
> #  .Random.seed is not an integer vector but of type 'promise'
>
> typeof(.Random.seed)
> # [1] "integer"
>
> So there must be an "attribute" "promise" somewhere
attached to
> .Random.seed, and I cannot find it. The R function typeof() does not
> reveal it, but the TYPEOF() function in src/main/RNG.c says it is a
> 'promise'.
You can remove it by a simple assignment:

.Random.seed <- .Random.seed

will do it.  (The reason is that it doesn't copy the object blindly, it 
evaluates the RHS to get 1L, and it's a regular assignment, so that gets 
put into the LHS.)

Duncan Murdoch
>
> My question is, how to make R use the real value of .Random.seed
> instead of complaining about the promise? Thanks!
>
> Regards,
> Yihui
> --
> Yihui Xie<xieyihui at gmail.com>
> Phone: 515-294-2465 Web: http://yihui.name
> Department of Statistics, Iowa State University
> 2215 Snedecor Hall, Ames, IA
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.