feature request: pseudo-tag for accessing the trunk

[Alex Tomlinson]

Many times I have found it would be useful to have a pseudo-tag that
when used in place of a real tag, would refer to the trunk.  For
example, the pseudo-tag could be TRUNK (much like HEAD and BASE).  Here
are two situations where I have found it would be useful:

1.  I've written a suite of scripts for folks in our company to do
    things like: checkout, update, checkout/build, checkout/build/archive.
    Having a name like TRUNK means I could always use "-r $tag" instead
    of having a special case for the trunk.

2. We have a tagging scheme that uses tags of the form:

        ${branch}
        ${branch}_${buildid}    // an archived build

   Once again, without a name like TRUNK, I have to implement a special
   case for tags that live on the trunk.

Thanks for your consideration,
Alex Tomlinson