table name as function argument?

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Hi, I'm fairly new to postgres and was wondering how would I go about using an argument passed into a user function to refer to a table.

As an example, consider the code below where I want to see if a table has any rows in it (this isn't what I'm trying to achieve but just the easiest thing I could think of to demonstrate what my problem is).

CREATE OR REPLACE FUNCTION istableempty("varchar", "char")
RETURNS bool AS
DECLARE
found int2;
BEGIN
SELECT into found count(*) FROM $1 WHERE rowid=$2;
IF found = 0
THEN
RETURN true;
ELSE
RETURN false;
END IF;
END

If I try to run, it tells me I have an error at or near the $1

Can anyone cast some light as to how I might be able to use an argument to refer to a table?

Thanks,

L

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