[Rd] dump function and compatibility of .RData files between versions 2.4/2.5 and lower (PR#9676)

[frederic.gosselin at cemagref.fr]

Full_Name: frédéric Gosselin
Version: 2.5 & 2.2.1
OS: windows XP pro
Submission from: (NULL) (195.221.118.52)


(i) I cannot read .Rdata saved with R2.5 with R2.2.1. I think it was the same
with R2.4 vs R2.2.1.

(ii) I have found the strange following problem, using the dump function:
dump(ls(),"text.txt")

in the text.txt file, there are a lot of "L" added at the end of numbers,
particularly in the .Dim attributes. This makes the file undreadable (at least
in R2.2.1 but alos probably in S-Plus...)

I do not know in which respect both potential bugs are related.