proc
    Astar(var/node/startnode,var/node/endnode)
        var/list/checked = list()   //keep track of where we've been already
        var/list/checking = list()    //where we still need to check
        var/list/lastnode = list()    //keep track of how we got to each node
        var/list/path  //used for the final return

        var/node/cur  //the currently being checked node

        checking += startnode //seed the list with our start value
        checked[startnode] = 1

        while(checking.len) //keep checking as long as we have places to go
            cur = checking[1]
            checking -= cur

            if(cur==endnode)
                //reconstruct the path
                path = list()
                while(cur!=startnode)
                    path.Insert(1,cur)
                    cur = lastnode[cur]
                return path

            for(var/node/n in cur.links) //check all neighbors
                if(!checked[n]) //if it's a fresh link
                    checking += n
                    checked[n] = 1
                    lastnode[n] = cur
        //pathfinding failed
        return null