// Instantiates a projectile off every 0.5 seconds,
    // if the Fire1 button (default is ctrl) is pressed.
    var projectile : GameObject;
    var fireRate = 0.5;
    private var nextFire = 0.0;
    function Update () {
        if (Input.GetButton ("Fire1") && Time.time > nextFire) {
            nextFire = Time.time + fireRate;
            var clone = Instantiate (projectile, transform.position, transform.rotation);
        }
    }

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public GameObject projectile;
    public float fireRate = 0.5F;
    private float nextFire = 0.0F;
    void Update() {
        if (Input.GetButton("Fire1") && Time.time > nextFire) {
            nextFire = Time.time + fireRate;
            GameObject clone = Instantiate(projectile, transform.position, transform.rotation) as GameObject;
        }
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public projectile as GameObject

    public fireRate as single = 0.5F

    private nextFire as single = 0.0F

    def Update():
        if Input.GetButton('Fire1') and (Time.time > nextFire):
            nextFire = (Time.time + fireRate)
            clone as GameObject = Instantiate(projectile, transform.position, transform.rotation)