VHDL fast fourier transform butterfly architecture problem.

Hello,

So this is my code for the butterfly architecture of my
program.......... when compiled it says : component(40): "add":
expecting ';'

component(41): "sub": expecting ';' and it continues so on for all the
other components..........

my code is as follows:

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.MATH_REAL.ALL;
library work;
use work.fft_pkg.all;

entity butterfly is
port(
s1,s2 : in complex; --inputs
w :in complex; -- phase factor
x1_out,x2_out ut complex -- outputs
);
end butterfly;

architecture Behavioral of butterfly is

signal xxx : integer := 0;

type comp_array is array (0 to 7) of complex;
type comp_array2 is array (0 to 3) of complex;

function add (x1,x2,x3 : comp_array) return comp_array;
function sub (x1,x2,x3 : comp_array) return comp_array;
function mult (x1,x2,x3 : comp_array) return comp_array;
begin

--butterfly equations.


function sub (x1,x2,x3 : comp_array) return comp_array is
variable diff : comp_array;

x1(1) := s(0) sub (s(4) mult w);

x1(3) := s(2) sub (s(6) mult w);

x1(5) := s(1) sub (s(5) mult w);


--2nd stage equations:

x2(2) := x1(0) sub (x1(2) mult w(0));

x2(1) := x1(1) sub (x1(3) mult w(2));

x2(4) := x1(4) sub (x1(6) mult w(0));

x2(5) := x1(5) sub (x1(7) mult w(2));

--3rd stage equations:


x3(4) := x2(0) sub (x2(4) mult w(0));

X3(5) := x2(1) sub (x2(5) mult w(1));

x3(6) := x2(2) sub (x2(6) mult w(2));

x3(7) := x2(3) sub (x2(7) mult w(3));
return diff;
end sub;


--1st stage equations:
function add (x1,x2,x3 : comp_array) return comp_array is
variable sum : comp_array;

x1(0) := s(0) add (s(4) mult w);
x1(2) := s(2) add (s(6) mult w);
x1(4) := s(1) add (s(5) mult w);
x1(6) := s(3) add (s(7) mult w);
--2nd stage equations (sum):
x2(0) := x1(0) add (x1(2) mult w(0));
x2(3) := x1(1) add (x1(3) mult w(2));
x2(6) := x1(4) add (x1(6) mult w(0));
x2(7) := x1(5) add (x1(7) mult w(2));
--3rd stage equations(sum):
x3(0) := x2(0) add (x2(4) mult w(0));
x3(1) := x2(1) add (x2(5) mult w(1));
x3(2) := x2(2) add (x2(6) mult w(2));
x3(3) := x2(3) add (x2(7) mult w(3));
return sum;
end add;


end process;


end Behavioral;