On 10/30/2009 9:30 AM, Michael Friendly wrote:
In my .Rprofile I have the following functions which display the
current directory in the main R window title bar,
and modify base::setwd() to keep this up to date. I like this because I
can always tell where I am in the file system.
cd <- function(dir) {
base::setwd(dir)
utils::setWindowTitle( short.path(base::getwd()) )
}
short.path <- function(dir, len=2) {
np <-length(parts <- unlist(strsplit(dir, '/')))
parts <-rev( rev(parts)[1:min(np,len)] )
dots <- ifelse (np>len, '...', '')
paste(dots,paste(parts, '/', sep='', collapse=''))
}
utils::setWindowTitle(short.path(base::getwd()))
utils::assignInNamespace("setwd",
function(dir){
.Internal(setwd(dir))
utils::setWindowTitle( short.path(base::getwd()) )
},
"base")
I would guess this would be fixed if you save the value from the
.Internal call, and return it as the result of your function, the way
the standard setwd does. A safer approach would be something like this:
local({
oldsetwd <- setwd
utils::assignInNamespace("setwd",
function(dir) {
value <- oldsetwd(dir)
utils::setWindowTitle( short.path(base::getwd()) )
value
}, "base")
})
This way, if the internals of setwd() ever change, your function won't
break.
Duncan Murdoch
However, this causes errors in some cases where setwd is used by other
functions, particularly example():
> library(HistData)
> example(Snow)
Error in setwd(olddir) : cannot change working directory
> traceback()
6: setwd(olddir)
5: open.srcfile(srcfile, first)
4: open(srcfile, first)
3: getSrcLines(srcfile, lastshown + 1, srcref[3L])
2: source(zfile, local, echo = echo, prompt.echo = paste(prompt.prefix,
getOption("prompt"), sep = ""), continue.echo = paste(prompt.prefix,
getOption("continue"), sep = ""), verbose = verbose,
max.deparse.length = Inf,
encoding = encoding, skip.echo = skips, keep.source = TRUE)
1: example(Snow)
>
Questions:
* Is there someway I can re-write these functions to avoid such problems?
* Is there someway I can 'hide' my custom functions like cd(),
short.path() so they don't appear in the global
environment but are available in my R session?
thanks
-Michael
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