subversion: How to: difference between modified working copy and alternate branch?

Seems that subversion doesn't allow to compare working copy with url. Both --old and --new need to be either WC or URL.

I think there's a workaround though - you may checkout your xxx branch and then compare 2 working copies.

svn checkout svn://foo.net/svn/repo/branch/xxx xxx_branch

svn diff xxx_branch yyy_modified_wc

diff -u xxx_branch yyy_modified_wc

Edit As Pavel noticed svn diff in this form doesn't compare xxx and yyy - it just shows local modifications of xxx and yyy. svn diff --old=xxx --new=yyy seems not allowed (at least in svn client 1.6.17). To compare xxx and yyy diff command is needed. Pavel, 10x for the notice