[Rd] bquote/evalq behavior changed in R-3.2.1

[William Dunlap]

Another aspect of the change is (using TERR's RinR package):
> options(REvaluators=list(makeREvaluator("R-3.1.3"),
                                           makeREvaluator("R-3.2.0")))
> RCompare(rapply(list(quote(function(x)x),list(quote(pi),quote(7-4))),
function(arg)typeof(arg)))
     R version 3.1.3 (2015-03-09) R version 3.2.0 (2015-04-16)
[1,] [1] "closure" "double"       [1] "language" "symbol"
[2,] [3] "double"                 [3] "language"
  $all.equal
  $all.equal$`R version 3.1.3 (2015-03-09) vs. R version 3.2.0 (2015-04-16)`
  [1] "3 string mismatches"

I prefer the new semantics, but it is a change.



Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, Jul 15, 2015 at 1:25 PM, David Winsemius <dwinsemius at comcast.net>
wrote:

>
> On Jul 15, 2015, at 12:51 PM, William Dunlap wrote:
>
> > I think rapply() was changed to act like lapply() in this respect.
> >
>
> When I looked at the source of the difference, it was that typeof()
> returned 'language' in 3.2.1, while it returned 'list' in the earlier
> version of R. The first check in rapply's code in both version was:
>
>  if (typeof(object) != "list")
>         stop("'object' must be a list")
>
> Wrapping list() around the first argument and switching to using eval with
> an expression-object rather than a call-object seemed to solve the problem
> when this was posed as a question on StackOverflow, but Dayne was not happy
> with that solution for other reasons that he is not describing.
>
> --
> David.
>
> > In R-3.1.3 we got
> > rapply(list(quote(1+myNumber)), evalq, envir=list2env(list(myNumber=17)))
> > #[1] 18
> > rapply(list(quote(1+myNumber)), eval, envir=list2env(list(myNumber=17)))
> > #Error in (function (expr, envir = parent.frame(), enclos = if
> > (is.list(envir) ||  :
> >  object 'myNumber' not found
> > lapply(list(quote(1+myNumber)), evalq, envir=list2env(list(myNumber=17)))
> > #Error in eval(substitute(expr), envir, enclos) : object 'X' not found
> > lapply(list(quote(1+myNumber)), eval, envir=list2env(list(myNumber=17)))
> > #[[1]]
> > #[1] 18
> > while in R-3.2.0 we get
> > rapply(list(quote(1+myNumber)), evalq, envir=list2env(list(myNumber=17)))
> > #Error in eval(substitute(expr), envir, enclos) : object 'X' not found
> > rapply(list(quote(1+myNumber)), eval, envir=list2env(list(myNumber=17)))
> > #[1] 18
> > lapply(list(quote(1+myNumber)), evalq, envir=list2env(list(myNumber=17)))
> > #Error in eval(substitute(expr), envir, enclos) : object 'X' not found
> > lapply(list(quote(1+myNumber)), eval, envir=list2env(list(myNumber=17)))
> > #[[1]]
> > #[1] 18
> >
> > Make the FUN argument function(arg)sys.call() to see some details of the
> > change.
> >
> >
> > Bill Dunlap
> > TIBCO Software
> > wdunlap tibco.com
> >
> > On Wed, Jul 15, 2015 at 12:35 PM, Dayne Filer <dayne.filer at gmail.com>
> wrote:
> >
> >> In 3.1.2 eval does not store the result of the bquote-generated call in
> >> the given environment. Interestingly, in 3.2.1 eval does store the
> result
> >> of the bquote-generated call in the given environment.
> >>
> >> In other words if I run the given example with eval rather than evalq,
> on
> >> 3.1.2 "x" is never stored in "fenv," but it is when I run the same code
> on
> >> 3.2.1. However, the given example stores "x" in "fenv" on 3.1.2, but
> throws
> >> the error I gave when run on 3.2.1.
> >>
> >> To give credit, I received the idea for using evalq from SO:
> >> http://stackoverflow.com/a/22559385
> >>
> >> Dayne
> >>
> >>
> >> On Wed, Jul 15, 2015 at 3:29 PM, William Dunlap <wdunlap at tibco.com>
> wrote:
> >>
> >>> I am curious why you used evalq instead of eval in this code.
> >>>
> >>> Bill Dunlap
> >>> TIBCO Software
> >>> wdunlap tibco.com
> >>>
> >>> On Wed, Jul 15, 2015 at 11:49 AM, Dayne Filer <dayne.filer at gmail.com>
> >>> wrote:
> >>>
> >>>> Hello,
> >>>>
> >>>> I upgraded from 3.1.2 to 3.2.1 and am receiving errors on code that
> >>>> worked
> >>>> as I intended previously. Briefly, I am using bquote to generate
> >>>> expressions to modify data.table objects within a  function, so I need
> >>>> the
> >>>> changes to actually be stored in the given environment. Previously, I
> >>>> used
> >>>> code like the following:
> >>>>
> >>>> test <- list(bquote(x <- 10))
> >>>> fenv <- environment()
> >>>> rapply(test, evalq, envir = fenv)
> >>>>
> >>>> Although the code in the example above is much simpler, it shows the
> >>>> problem. On 3.1.2 the expression is evaluated and x is stored as 10 in
> >>>> the
> >>>> given environment, fenv. In 3.2.1 the code throws an error:
> >>>>
> >>>> Error in eval(substitute(expr), envir, enclos) : object 'X' not found
> >>>>
> >>>> I could not find anything in the release notes that would explain this
> >>>> change. Changing evalq to eval works in 3.2.1, but eval does not
> store x
> >>>> in
> >>>> the given environment in 3.1.2.
> >>>>
> >>>> Thanks,
> >>>>
> >>>> Dayne
> >>>>
> >>>>        [[alternative HTML version deleted]]
> >>>>
> >>>> ______________________________________________
> >>>> R-devel at r-project.org mailing list
> >>>> https://stat.ethz.ch/mailman/listinfo/r-devel
> >>>>
> >>>
> >>>
> >>
> >
> >       [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-devel at r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-devel
>
> David Winsemius
> Alameda, CA, USA
>
>

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