Massimiliano Mirra <list / chromatic-harp.com> wrote in message 
[snip]
> Thanks a lot, Thomas.  Please shed some light on a couple of points:
> does rubyzip only decompress?  (Which would be fine for our purposes!)

So far yes - adding rudimentary support for writing zip files is not
difficult, though.

> You say that it depends on ruby/zlib for decompression of .zip, but
> doesn't ruby/zlib handle .gz's?  

Yes ruby/zlib handles .gz files. It also provides raw
deflation/inflation compression/decompression. deflation is the
(commonly used) compression scheme in .zip files.

> Does ruby/zlib run effortlessly on
> every Ruby-supported platform?

I think zlib is probably as portable as ruby. There is a long list of
binaries for any odd platform at http://www.gzip.org/zlib/. I don't
know about the ruby/zlib wrapper, but it should - shouldn't it.