tarball URL conventions and sptools

I'm working on a new command for sptools, sp-download, that handles
downloads of package tarballs.  Given a package name, it fetches and
parses <URL:http://cr.yp.to/slashpackage/list.html> to find that
package's URL.  But the exact URL for the tarball cannot quite be
determined from just the URL on that page; different package authors
have different conventions for their web site layouts.  It probably
isn't feasible to get all authors to use the same URL convention, so
instead I suggest adding more information to slashpackage/list.html.
For example:
<li><a href="http://cr.yp.to/daemontools.html">admin/daemontools</a><!-- tardir: daemontools/ -->
<li><a href="http://multivac.cwru.edu/sptools/">admin/sptools</a>:manage /package installations<!-- tardir: releases/ -->

sp-download could parse out the URL with sed, drop everything after
the last "/", append the specified tardir, and append
"daemontools-0.76.tar.gz", "sptools-2003.10.31.tar.bz2", etc., to
construct the full tarball URL.

The above format is just an example.  Comments probably aren't the
best way to hold structured data in a markup language.  And Dan, if
you're planning to make any other changes to the format of
slashpackage/list.html, please do it soon and/or let me know so
sp-download will continue to work.

Once tarball directories become knowable, you'll be able to say
"sp-install /package/admin/daemontools-0.76", and it'll all Just Work:
if the given package directory doesn't already exist, the tarball will
be unpacked; if the tarball isn't already stored locally, it will be
downloaded first.  Then the package will be installed.

It would also be useful to be able to say
"sp-install /package/admin/daemontools", and have sp-* inspect the
daemontools website to determine the latest version and install that.
I'm not sure how that information should be represented.


paul