CREATE OR REPLACE FUNCTION palindrom ( NAME IN VARCHAR2
                                     )
                                     RETURN BOOLEAN
IS
  n NUMBER;
  v_name VARCHAR2(100);
  t_name VARCHAR2(100);
BEGIN
  n:=LENGTH(NAME);
  FOR
    i IN 1..n 
  LOOP
    v_name:=SUBSTR(NAME,1,n);
    t_name:=t_name||SUBSTR(NAME,n-i+1,1);
  END LOOP;
  IF
    v_name<>t_name 
  THEN
    RETURN FALSE;
  ELSE
  RETURN TRUE;
END IF;
END;

CREATE FUNCTION is_palindrome(p_string IN VARCHAR2)
RETURN BOOLEAN
IS
   v_string VARCHAR2(100);
BEGIN
  -- cheating by using the undocumented
  -- "reverse" SQL function
  SELECT REVERSE(p_string)
  INTO   v_string
  FROM   dual;
  
  -- Applying Frank's advice
  RETURN p_string = v_string;
END is_palindrome;
/
sho err

set serverout on

var a VARCHAR2(100)

exec :a := 'civic';

--
-- Test it in PL/SQL: boolean functions cannot
-- be used in SQL
--
Begin
  if is_palindrome(:a)
  then
    dbms_output.put_line(:a||' is a palindrome ');
  else
    dbms_output.put_line(:a||' is not a palindrome ');  
  end if;  
End;
/

exec :a := 'another';
/

DROP function is_palindrome
/