Re: [R] weirdness in sourc()ing a dump() (bug?)

About this list Date view Thread view Subject view Author view Attachment view

From: Peter Dalgaard (p.dalgaard@biostat.ku.dk)
Date: Thu 06 May 2004 - 06:50:50 EST


Message-id: <x265ba61jp.fsf@biostat.ku.dk>

Prof Brian Ripley <ripley@stats.ox.ac.uk> writes:

> On Wed, 5 May 2004, Duncan Murdoch wrote:
>
> > On Wed, 5 May 2004 20:20:51 +0100 (BST), Prof Brian Ripley
> > <ripley@stats.ox.ac.uk> wrote :
> >
> > >I don't think it is a bug. Note that dump does not even claim to dump
> > >lists let alone symbols, but ?dump says
> > >
> > > At present the implementation of 'dump' is very incomplete and it
> > > really only works for functions and simple vectors.
> > >
> > >Given that, this is not unexpected. (Looks like more than one person did
> > >not check the help page ....)
> > >
> > >I think save/load is a much safer way to handle saving R objects, and it
> > >does work in PD's example.
> >
> > I'd still call it a bug, since 'dump("x"); source("dumpdata.R")' could
> > change the meaning of x without any warning, and that can't be
> > desirable behaviour.
>
> That's not what it says it does, and not what the S version achieves
> either. (Do see the documentation on `what is a bug' in the FAQ, which
> does not agree with you.)

Weelll.. The goal of dump/dput is to create a construct that can be
evaluated so as to yield the original object. This is one place where
we fail to meet that goal, so I'll call it a bug, documented or not.
Especially, since it is something we might actually be able to fix
fairly simply (note "might" -- we've had our share of "fixes" that
didn't in the deparsing area).

> I was trying to be constructive: save/load *is* supposed to reproduce
> objects, and it just not realistic to get dump/source to do that. And we
> do warn about it in the documentation and I can see nowhere that
> recommends dump/save as a way of saving objects .... (If there is such a
> place, then that is a bug and needs fixing.)

I don't disagree that save/load is a better strategy for data storage,
but dump and friends do have the potential to create an *editable*
text representation, so there is some point in trying to make them
work predictably as far as possible.

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907

______________________________________________ R-help@stat.math.ethz.ch mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html


About this list Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.3 : Mon 31 May 2004 - 23:05:07 EST