CREATE TABLE - DEFAULT

I'll try sending my question again.
Can you help me?!

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Hello again!

I have been receiving some mails asking my question about creating a table
with a default value as a user defined function, but I have a problem yet.

I hope somebody knows to solve my problem...
Thank you in advance! :)

//Ingrith

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Te complete problem is:

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CREATE TABLE emp (code INT4
  , name VARCHAR(20)
  , salary INT4
  , 2salary INT4 default double_salary(emp)
);

CREATE FUNCTION double_salary(emp) RETURNS INT4
AS 'SELECT $1.salay * 2 AS result' LANGUAGE 'sql'
;

ERROR:  parser: syntax error at or near ")"
---------------------------------------------------------

Function double_salary receives an 'emp' , as you see, and there is the
error, because if I change parameter 'emp' by a number, the error doesn't
appear.

How can I do?!

The origin of this question is that I want to know if a subclass inherits
all atributtes from the parent, included functions like double_salary in
my example.