speedbump in library
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. phaverty at gene.com
On Fri, Jan 23, 2015 at 8:15 AM, Winston Chang <winstonchang1 at 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.peter at 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. phaverty at gene.com ______________________________________________ R-devel at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel