Because I couldn't decide what to do about the delimiter-prefix issue, where %f1 could potentially cause issues for script users, I made the shape of the switches OS dependent (%f1...%fn for unix, ---f1... for windows) and also added a feature that allows people to change that prefix, so you could say svn diff --invoke-diff-cmd="# diff -u #f1 #f2" if you want, and use '$', '-' or even '---' etc.
Not such a good idea(it was fun to code though) because changing the user interface across platforms is disorienting.
I also rewrote svn_io_create_custom_diff_cmd() to use svn_string_buf_t instead of the string.h functions I used previously.
However, for now, I'm feeling somewhat strfry(Gabriela) and so I'll take a little break from --invoke-diff-cmd to let the concepts I've learned settle, and instead have a go at writing a short introduction to the SVN_DBG tool for the HACKING guide -- watch this space :)
