Michael Heerdegen <michael_heerdegen@web.de> writes:
> We don't need another function.  You only need to say that TESTFN is not
> necessarily an equality predicate or symmetric.  And in which order the
> two arguments are passed (and have a look that your current calling order
> is so that the above example works as expected).

Very clear. See attached patch for the new version. I also added a unit
test to make sure the result is what you expect.

-- 
Damien Cassou

"Success is the ability to go from one failure to another without
losing enthusiasm." --Winston Churchill