# example from utPLSQL project (http://utplsql.sourceforge.net/)
plsql.execute <<-SQL
CREATE OR REPLACE FUNCTION betwnstr (
   string_in   IN   VARCHAR2,
   start_in    IN   INTEGER,
   end_in      IN   INTEGER
)
   RETURN VARCHAR2
IS
   l_start PLS_INTEGER := start_in;
BEGIN
   IF l_start = 0
   THEN
      l_start := 1;
   END IF;

   RETURN (SUBSTR (string_in, l_start, end_in - l_start + 1));
END;
SQL