[Gnu-arch-users] self-contained changesets?

[Joshua Haberman]

Arch seems to require that anyone who wants to make their personal
changes available to the world have access to a publically available
server to host their personal archive.  Is this a safe assumption?

Also, for the case where someone wants to make small changes to an
arch-versioned tree, the process of creating an archive, branching, and
publishing the archive seems like overkill.

Is it possible to implement a command similar in spirit to "cvs diff?" 
What I mean is that such a command would produce a self-contained
changeset that doesn't have to be part of an archive, that could then be
sent independently (say, as an attachment to email).   Such as changeset
would ideally apply as cleanly as possible even if the branch from which
it was generated changed in the meantime.

In other words, I want to be able to generate an independent changeset
against a tree that I can apply at any point in the future to that
branch or its ancestors and have tla "do the right thing."

Josh