Simon Urbanek wrote :
Can you elaborate on the details as of where this will be a problem?
Packages
should not be affected since they should be importing the namespaces
from the
packages they use, so the only problem would be in a package that
uses both
data.table and rJava -- and this is easily resolved in the namespace
of such
package. So there is no technical reason why you can't have multiple
definitions of J - that's what namespaces are for.
Right. It's users using J() in their own code, iiuc. rJava's manual
says "J is
the high-level access to Java." When they use J() on its own they
probably
want the rJava one, but if data.table is higher they get that one.
They don't want to have to write out rJava::J(...).
It is not just rJava but package XLConnect, too. If there's a better
way would
be interested but I didn't mind removing J from data.table.
Bunny/Matt,
To add to Steve's reply here's some background. This is well documented
in NEWS
and Googling "data.table J rJava" and similar returns useful links to
NEWS and
datatable-help (so you shouldn't have needed to post to r-devel).
From 1.8.2 (Jul 2012) :
o The J() alias is now deprecated outside DT[...], but will still work
inside
DT[...], as in DT[J(...)].
J() is conflicting with function J() in package XLConnect (#1747)
and rJava (#2045). For data.table to change is easier, with some
efficiency
advantages too. The next version of data.table will issue a warning
from J()
when used outside DT[...]. The version after will remove it. Only
then will
the conflict with rJava and XLConnect be resolved.
Please use data.table() directly instead of J(), outside DT[...].
From 1.8.4 (Nov 2012) :
o J() now issues a warning (when used *outside* DT[...]) that using it
outside DT[...] is deprecated. See item below in v1.8.2.
Use data.table() directly instead of J(), outside DT[...]. Or,
define
an alias yourself. J() will continue to work *inside* DT[...] as
documented.
From 1.8.7 (soon to be on CRAN) :
o The J() alias is now removed *outside* DT[...], but will still work
inside DT[...];
i.e., DT[J(...)] is fine. As warned in v1.8.2 (see below in this
file) and deprecated
with warning() in v1.8.6. This resolves the conflict with function
J() in package
XLConnect (#1747) and rJava (#2045).
Please use data.table() directly instead of J(), outside DT[...].
Matthew
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