savehistory directories and quitting R (PR#2038)

[Mark.Bravington@csiro.au]

Thanks-- as Duncan Murdoch also noted, R_HISTFILE can be used to solve my
problem, as below. BTW it's not easy to find out about R_HISTFILE in the
help system or manuals, though, unless you already know it exists-- it only
seems to be described under startup options, not things to do with history.

However, Duncan's reply did hint at an inconsistency, in that savehistory()
defaults to using a file called .Rhistory in getwd(), rather than using
R_HISTFILE. I've modified my savehistory to default to R_HISTFILE if it
exists, like so:

savehistory_ function( file) {
  if( missing( file) && is.null( file <- Sys.getenv( 'R_HISTFILE')))
    file <- '.Rhistory'
  get( 'savehistory', pos='package:base')( file)
}

#This is not a bug. If you override a system function, you 
#can't expect it
#to be used by R internals.  Indeed, as from 1.6.0 you can't 
#even expect it
#to be used by R's base functions, due to namespaces.

With an eye to namespace-like issues, I originally put some code in .First
to overwrite the version of savehistory within package:base, rather than
simply masking it with a copy in .GlobalEnv. But, since savehistory wasn't
actually called at quit time, even that didn't fool the system...

cheers
Mark

*******************************

Mark Bravington
CSIRO (CMIS)
PO Box 1538
Castray Esplanade
Hobart
TAS 7001

phone (61) 3 6232 5118
fax (61) 3 6232 5012
Mark.Bravington@csiro.au 

#-----Original Message-----
#From: ripley@stats.ox.ac.uk [mailto:ripley@stats.ox.ac.uk]
#Sent: Tuesday, 15 October 2002 12:31 AM
#To: Mark.Bravington@csiro.au
#Cc: r-devel@stat.math.ethz.ch; R-bugs@biostat.ku.dk
#Subject: Re: savehistory directories and quitting R (PR#2038)
#
#
#This is not a bug. If you override a system function, you 
#can't expect it
#to be used by R internals.  Indeed, as from 1.6.0 you can't 
#even expect it
#to be used by R's base functions, due to namespaces.
#
#There are very good reasons for the internal quit code not to 
#call user's
#R code, the main one being that R errors will not be handled then.
#.Last is made available as a hook to enable you to do what you want:
#as the help page says.
#
#Doesn't setting R_HISTFILE do this for you automatically? Just set
#R_HISTFILE="D:/R50/.Rhistory" and the history should be loaded 
#and saved
#to the specified place.  Works under Unix, at least.
#
#
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