array constructor can't construct empty array

Hello

I have function 

CREATE FUNCTION foo(date, date, INTEGER[]) RETURNS INTEGER 

Array and array's functions works fine, but I need call this function 
with empty array. I can't use array constructor for empty array. When 
I call function foo with e.a. ,I get syntax error. I can call with '{}'.

What is coorect style?

Thank You 
Pavel Stehule