Thanks Winston,
Yes, your version of that part is more direct. I guess it would need a
! is.null() too. I think we should use .getNamespace.
It It also occurred to me that this %in% check (which happens in a few
places) is kind of roundabout. It equates to
"foo" %in% ls(.Internal(getNamespaceRegistry()), all.names = TRUE)
We lack and R-level accessor for the namespace registry, but if we had
one we could do
getNamespaceRegistry()[["foo"]]
, which is just a hash lookup.
I'm getting a bit off topic here, but ...
"foo" %in% vector is a common pattern and reads well, but
any(vector == "foo")
is less work and much faster. I wonder if there is room for a fast
path there ...
Pete
____________________
Peter M. Haverty, Ph.D.
Genentech, Inc.
phave...@gene.com
On Fri, Jan 23, 2015 at 8:15 AM, Winston Chang <winstoncha...@gmail.com> wrote:
> I think you can simplify a little by replacing this:
> pkg %in% loadedNamespaces()
> with this:
> .getNamespace(pkg)
>
> Whereas getNamespace(pkg) will load the package if it's not already
> loaded, calling .getNamespace(pkg) (note the leading dot) won't load
> the package.
>
> I can't speak to whether there are any pitfalls in changing the
> library path searching, though.
>
> -Winston
>
>
> On Thu, Jan 22, 2015 at 12:25 PM, Peter Haverty <haverty.pe...@gene.com>
> wrote:
>> Hi all,
>>
>> Profiling turned up a bit of a speedbump in the library function. I
>> submitted a patch to the R bug tracker as bug 16168 and I've also
>> included it below. The alternate code is simpler and easier to
>> read/maintain, I believe. Any thoughts on other ways to write this?
>>
>> Index: src/library/base/R/library.R
>> ===================================================================
>> --- src/library/base/R/library.R (revision 67578)
>> +++ src/library/base/R/library.R (working copy)
>> @@ -688,18 +688,8 @@
>> out <- character()
>>
>> for(pkg in package) {
>> - paths <- character()
>> - for(lib in lib.loc) {
>> - dirs <- list.files(lib,
>> - pattern = paste0("^", pkg, "$"),
>> - full.names = TRUE)
>> - ## Note that we cannot use tools::file_test() here, as
>> - ## cyclic namespace dependencies are not supported. Argh.
>> - paths <- c(paths,
>> - dirs[dir.exists(dirs) &
>> - file.exists(file.path(dirs,
>> - "DESCRIPTION"))])
>> - }
>> + paths <- file.path(lib.loc, pkg)
>> + paths <- paths[ file.exists(file.path(paths, "DESCRIPTION")) ]
>> if(use_loaded && pkg %in% loadedNamespaces()) {
>> dir <- if (pkg == "base") system.file()
>> else getNamespaceInfo(pkg, "path")
>>
>> Pete
>>
>> ____________________
>> Peter M. Haverty, Ph.D.
>> Genentech, Inc.
>> phave...@gene.com
>>
>> ______________________________________________
>> R-devel@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
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