[R] weirdness in sourc()ing a dump() (bug?)
Prof Brian Ripley
ripley at stats.ox.ac.uk
Wed May 5 21:50:29 CEST 2004
On Wed, 5 May 2004, Duncan Murdoch wrote:
> On Wed, 5 May 2004 20:20:51 +0100 (BST), Prof Brian Ripley
> <ripley at 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.)
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.)
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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