Oracle: Use of notational parameters which calling functions in insert statements not allowed?

Why does Oracle 10 R2 not allow use of notational parameters while calling functions in insert statements ?

In my app, I'm calling a function in an insert statement. If use notational method of parameter passing, I get an ORA-00907: Missing right parenthesis error message

INSERT INTO foo
 开发者_如何学JAVA           (a,
             b,
             c)
VALUES      (c,
             F1(P1=>'1', P2=>'2', P3 => '3'),
             e)

Changing the same to position based parameter passing, and the same code gets compiled with no errors.

INSERT INTO foo
            (a,
             b,
             c)
VALUES      (c,
             F1('1','2','3'),
             e) 

Why is this so ?

Because it was a feature added in 11g.