Offhand, I doubt that URLs starting with "-" occur anywhere in OpenACS
in practice.
But this is a good example of one of Tcl's minor but annoying warts.
I tend to habitually use "--" everywhere I think it might
work, until "Oops, got an error, oh yeah, this particular Tcl command
doesn't accept the '--' option, take it out."
And once you define a proc with no option switches at all, it seems
that for 100% backwards compatibility you must never
add any switches ever. Actually, hm, I suppose you could
kludge something into ad_returnredirect to check the number of
arguments it received, and implicitly add the "--" if necessary. That
means doing its own parsing rather than using ad_proc though, which is
probably both not worth it and a bad idea. Instead, perhaps it would
be worthwhile to extend ad_proc itself to optionally support some such
feature?
