"Special" characters in URI

I am crossposting this to R-help and BioC, since it is relevant to both
groups.

I don't see the relevance to R-help.  But the answer to your subject is 
unambiguous: valid URLs do not contain `special' characters -- they must 
be encoded.  See RFC1738 at e.g. ftp://ftp.funet.fi/pub/doc/rfc/rfc1738.txt

At some point (probably 2.2.0) I intend to ensure that the mapping to 
file:// URLs that is done is a few places is encoded as necessary.  This 
will likely result in a utility function filePathToURL or some such.

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