Support for hg svn?
Currently MacHg does work with svn through the use of the hgsubversion extension. Make sure you have the hgsubversion extension installed and test it using chg (see command line) and the kick-start tutorial.
Note: However, MacHg uses a system of repository identity checking which doesn't currently work well with with non-mercurial servers. (For example git can also be used through the hg-git extension but suffers the same problem.)
For instance when trying to set up a new server, if the server is svn or git based then MacHg will currently decide that these servers are unreachable. If you ignore this warning and just add them anyway, then you can clone, push, and pull from them, etc.
When using clone, push, pull, incoming, or outgoing in MacHg with these non-mercurial servers you have to manually check the option allowing a connection to all servers. For example see the following for the push dialog example:
Of course, MacHg fully works with the Mercurial repository once the conversion tools have been run. See WorkingWithSubversion, and hg-git. Further, note that MacHg has the "Export Patches..." command under the file menu, so you can graphically pick and select the set of patches you would like to export if you like working with patches.
Hopefully within the near future I will enhance the repository discovery and synchronization so it handles non-Mercurial servers in a better way.