Attach: Attach object cache

Description

Place a stored object cache one the search path, or change the position of such a cache already on the search path.

Usage

Attach(lib = Sys.getenv("R_LOCAL_CACHE", unset = ".R_Cache"),
       lib.loc = Sys.getenv("R_LOCAL_LIB_LOC", unset = "."),
       pos = 2, uniquely = TRUE, readonly = FALSE, ...)
AttachData(...)
AttachUtils(...)

Arguments

lib

The name of the cache directory from which items are to be removed. May be given as a character string, or as a name, (i.e. without quotes) for convenience. The default is as follows:

ForAttach, the value of theR

lib.loc

The enclosing directory where the cache directory is to be found.
    The default is as follows:
    ForAttach, the value of theRenvironment
	variableR_LOCAL_LIB_LOC, or the current working directory
	if unse

pos

The position on the search path where the object cache is to be
    placed, or the new position if the cache is already on the search
    path.

uniquely

Logical. Are multiple copies of the same cache on the search path to
    be disallowed?  If TRUE, a single copy only is left on the
    search path.

readonly

Logical.  If TRUE modifications to the objects in the cache
    are prevented.

...

Extra arguments to be passed on to internal SOAR functions.
    Presently unused.

`Value`

Nothing of interest.  The function is used solely for its side-effect on
the search path

`Details`

An existing object cache is attached to the search path.  If the
  object cache directory, file.path(lib.loc, lib), currently does
  not exist a warning is issued to that effect, but also advising that
  the directory will be created when an object is to be Stored
  there.

`References`

None

`See Also`

attach, detach.

`Examples`

## change default cache, keeping any previous setting
oldLC <- Sys.getenv("R_LOCAL_CACHE", unset = ".R_Cache")
Sys.setenv(R_LOCAL_CACHE=".R_Test")

## generate some dummy data
dummy <- rnorm(100)
mn <- mean(dummy)
va <- var(dummy)

Attach()                            # may give warning

## store it in the stored object cache
Store(dummy, mn, va)
Search()

Attach(pos=3)                       # change to pos=3
Search()

Objects()
Remove(mn, va)
Objects()
Remove(Objects())                   # empty the cache

detach(".R_Test")                   # remove from search path
Sys.setenv(R_LOCAL_CACHE=oldLC)     # restore normal default