PLSQL FUNCTION (variation of earlier question)

Question

-- Attempting to COMBINE two parts of
-- a table name using a function
-- 1. MANY tables begin with the string: -- FT
-- 2. each suffixed two digits refer to the -- year of
-- the data in the table
-- eg. TABLE FT99 includes all 1999 -- data
-- how can I fix this ?
-- is this a bad approach to the problem ?
create or replace function gca_f1 return varchar2 as
begin
return('ft'| |'&&yr1');
end;
variable pvl1 varchar2(10);
execute :pvl1 := gca_f1();
column p new_value p1;
select :pvl1 p1 from dual;
prompt this works up to this point
-- the following does pass the correct file -- name
select count(*) from &&p1;
null

Answer 1

-- x.sql WORKS ! BUT ... I DON'T UNDERSTAND.
-- WHY MUST {fun_var1} BE LOADED INTO {col2}
-- TWO TIMES TO GET A VALUE FROM {fnctn1} TO -- WORK ?
-- WHAT AM I MISSING ?
CREATE OR REPLACE FUNCTION fnctn1 RETURN VARCHAR2 AS
BEGIN
RETURN('ft'| |'&&yr1');
END;
VARIABLE fun_var1 VARCHAR2(10);
EXECUTE :fun_var1 := fnctn1();
-- FIRST TIME
COLUMN col1 NEW_VALUE col2;
SELECT :fun_var1 col2 FROM DUAL;
-- SECOND TIME
COLUMN col2 NEW_VALUE col3;
SELECT :fun_var1 col2 FROM DUAL;
SELECT COUNT(*) FROM &&col3;
-- NOTES:
-- This function combines two parts of a -- table name
-- 1. Tables begin with string: FT
-- 2. Suffix is two digits for: year
--eg. table FT99 includes data for 1999
null