Oolite Bulletins

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this.name = "MyPatchingOXP";

// Make sure our shipWillLaunchFromStation() runs after OtherOXP’s shipWillLaunchFromStation.

this.actual_shipWillLaunchFromStation = function (station)
{
    // Do stuff here
}


this.startUp = function ()
{
    // Must defer this to startUp() to ensure both scripts are loaded.
    if (worldScripts["OtherOXP"])
    {
        let otherOXP = worldScripts["OtherOXP"];
        
        if (otherOXP.shipWillLaunchFromStation)
        {
            // Note use of _this_ OXP’s name as unique prefix
            otherOXP.MyPatchingOXP_original_shipWillLaunchFromStation = otherOXP.shipWillLaunchFromStation;
        }
        else
        {
            // OtherOXP has no shipWillLaunchFromStation() handler yet.
            // For simplicity, we add a do-nothing handler. A simpler
            // patched shipWillLaunchFromStation() would also be an option.
            otherOXP.MyPatchingOXP_original_shipWillLaunchFromStation = function () {}
        }
        
        // Install patched shipWillLaunchFromStation() which calls both
        // OtherOXP’s handler and our actual handler in the desired order.
        otherOXP.shipWillLaunchFromStation = function (station)
        {
            // Note: here "this" refers to otherOXP’s script
            
            // Ensure OtherOXP’s handler runs first (“tail patch”).
            // Reversing the order (a “head patch”) is also possible.
            this.MyPatchingOXP_original_shipWillLaunchFromStation(station);
            worldScripts["MyPatchingOXP"].actual_shipWillLaunchFromStation(station);
        }
    }
    else
    {
        // OtherOXP is not installed. We could just do
        // this.shipWillLaunchFromStation = this.actual_shipWillLaunchFromStation,
        // but that would make it harder for other scripts to patch this one.
        this.shipWillLaunchFromStation = function (station)
        {
            this.actual_shipWillLaunchFromStation(station);
        }
    }
    
    delete this.startUp;
}