[Dbix-class] select * from function('param')

[mock]

So I've got a function in my Pg database which takes a single parameter and
returns a set of rows.

"select * from function('param')" works just fine from psql and returns all my
lovely rows just as I want them.  I can do all the useful things I might want
like "select * from function('param') where something = someotherthing" which
is really quite handy.  I'd like to be able to use this from DBIx::Class, but
I've not been able to find anything in the docs which describes doing this, and
I'm a bit confused as to where to look.  Doing the obvious
"$resultset = $schema->resultset("function(\'$param\')")->all" didn't seem to
do what I wanted.

Could I get some pointers as to if this is even possible, and where to look in
the docs if it is in order to make it work?

thanks
mock