help with bullet shooting code? - javascript

i purchased a tutorial from the assets store and everything is okay so far except for the bullet code. It's showing 5 errors on the console tab.

 1. Assets/Scripts/PlayerController.js(50,10): BCE0044: expecting (, found 'shoot'.
  2. Assets/Scripts/PlayerController.js(52,1): BCE0043: Unexpected token: var. 
  3. Assets/Scripts/PlayerController.js(52,4): UCE0001:';' expected. Insert a semicolon at the end.
  4. Assets/Scripts/PlayerController.js(52,5): BCE0043: Unexpected token: bullet_position.
  5. Assets/Scripts/PlayerController.js(56,1): BCE0044: expecting EOF, found '}'.

Here is what I have on my script so far (I don't know why it shows disorganized when I pasted it):

 #pragma strict
     public var player_speed : int = 10;
     public var screen_top:float = 1;
     public var screen_bottom:float = -8.5;
     public var screen_left:float = -12.5;
     public var screen_right:float = 12.5;
     public var player_position_x:float;
     public var player_position_y:float;
     public var bullet:GameObject;
 function Start ()
 {
 
 }
 
 function Update ()
 {
     player_position_x = transform.position.x;
     player_position_y = transform.position.y;
     if (Input.GetKey (KeyCode.UpArrow) || Input.GetKey(KeyCode.W))
     {
         if (player_position_y < screen_top)
         {
 transform.Translate (Vector3(0,0,-1) * Time.deltaTime*player_speed);
         }
     }
     if (Input.GetKey (KeyCode.DownArrow)|| Input.GetKey(KeyCode.S))
     {
         if (player_position_y > screen_bottom)
         {
 transform.Translate (Vector3(0,0,1) * Time.deltaTime*player_speed);
         }
     }
     if (Input.GetKey (KeyCode.LeftArrow)|| Input.GetKey(KeyCode.A))
     {
         if (player_position_x > screen_left)
         {
 transform.Translate (Vector3(1,0,0) * Time.deltaTime*player_speed);
         }
     }
     if (Input.GetKey (KeyCode.RightArrow)|| Input.GetKey(KeyCode.D))
     {
         if (player_position_x < screen_right)
         {
 transform.Translate (Vector3(-1,0,0) * Time.deltaTime*player_speed);
         }
 }
     if (Input.GetKey (KeyCode.Space))
     {
         shoot();
 function shoot();
 {
 var bullet_position:Vector3 = transform.position;
 var  spawned_bullet:GameObject = Instantiate(bullet, bullet_position, Quaternion.identity);
 }
     }
 }