pl/pgsql function with argument of type DATE

How to invoke function which has arguments declared as type “date”?

I want to make function which will return a list of all dates between starting and ending

 date which are two arguments of that function. I tried with:

select * from foo(2008-06-01, 2008-06-09)

select * from foo(‘2008-06-01’, ‘2008-06-09’)

but type mismatch (date vs integer) error occurs.

Thanks,

     Bojan