The difference in the outputs between 3.3 and 3.4 is in how call
expressions are selected in presence of .Internals. R is asked for a
call expression for "eval". In 3.3 one gets the arguments for the call
expression from the .Internal that implements eval. In 3.4 one gets the
arguments for the call expression from the closure wrapper of "eval",
which is less surprising. See e.g.
(3.4)
> evalq()
Error in evalq() : argument is missing, with no default
vs
(3.3)
> evalq()
Error in eval(substitute(expr), envir, enclos) :
argument is missing, with no default
(and yes, these examples work with sys.call() and lattice originally
used it in xyplot - perhaps it'd be best to submit a bug report/issue
for lattice)
Tomas
On 05/09/2017 11:06 PM, William Dunlap via R-devel wrote:
Some formula methods for S3 generic functions use the idiom
returnValue$call <- sys.call(sys.parent())
to show how to recreate the returned object or to use as a label on a
plot. It is often followed by
returnValue$call[[1]] <- quote(myName)
E.g., I see it in packages "latticeExtra" and "leaps", and I suspect it
used in "lattice" as well.
This idiom has not done good things for quite a while (ever?) but I noticed
while running tests that it acts differently in R-3.4.0 than in R-3.3.3.
Neither the old or new behavior is nice. E.g., in R-3.3.3 we get
parseEval <- function(text, envir) eval(parse(text=text), envir=envir)
parseEval('lattice::xyplot(mpg~hp, data=datasets::mtcars)$call',
envir=new.env())
xyplot(expr, envir, enclos)
and
evalInEnvir <- function(call, envir) eval(call, envir=envir)
evalInEnvir(quote(lattice::xyplot(mpg~hp, data=datasets::mtcars)$call),
envir=new.env())
xyplot(expr, envir, enclos)
while in R-3.4.0 we get
parseEval <- function(text, envir) eval(parse(text=text), envir=envir)
parseEval('lattice::xyplot(mpg~hp, data=datasets::mtcars)$call',
envir=new.env())
xyplot(parse(text = text), envir = envir)
and
evalInEnvir <- function(call, envir) eval(call, envir=envir)
evalInEnvir(quote(lattice::xyplot(mpg~hp, data=datasets::mtcars)$call),
envir=new.env())
xyplot(call, envir = envir)
Should these packages be be fixed up to use just sys.call()?
Bill Dunlap
TIBCO Software
wdunlap tibco.com
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