Running multiple Loop decorators in parallel with syncronization

[MikeWrock]

Suppose I had a vector of velocities, and a vector of waypoints. I want to iterate through each waypoint and drive at the corresponding velocity. In the waypoints example a LoopDouble and LoopPose decorator is used, however the {number} from LoopDouble cannot be used with UseWaypoint in LoopPose:

 <root BTCPP_format="4" >
     <BehaviorTree ID="TreeA">
        <Sequence>
            <LoopDouble queue="1;2;3"  value="{number}">
              <PrintNumber value="{number}" />
            </LoopDouble>

            <GenerateWaypoints waypoints="{waypoints}" />
            <LoopPose queue="{waypoints}"  value="{wp}">
              <UseWaypoint waypoint="{wp}" />
            </LoopPose>
        </Sequence>
     </BehaviorTree>
 </root>

What would be the best approach to using the LoopDouble queue in LoopPose?

I have considered a couple options:

Combine LoopDouble and LoopPose

 <root BTCPP_format="4" >
     <BehaviorTree ID="TreeA">
        <Sequence>
            <GenerateWaypoints waypoints="{waypoints}" />
            <LoopDoubleAndPose pose_queue="{waypoints}"  pose_value="{wp}" vel_queue="1;2;3"  vel_value="{velocity}">
              <UseWaypoint waypoint="{wp}" velocity="{velocity}"/>
            </LoopDoubleAndPose>
        </Sequence>
     </BehaviorTree>
 </root>

Create a SyncronizedParallelLoop decorator

This node requires multiple Loop children each with the same size queue, then it will tick each child once. In essence, a for loop that passes the current index to each child.

 <root BTCPP_format="4" >
     <BehaviorTree ID="TreeA">
        <Sequence>
            <GenerateWaypoints waypoints="{waypoints}" />
            <SyncParallelLoop queue_size="3">
              <LoopPose queue="{waypoints}"  value="{wp}" />
              <LoopDouble queue="1;2;3"  value="{velocity}" />
              <UseWaypoint waypoint="{wp}" velocity="{velocity}" />
            </SyncParallelLoop>
        </Sequence>
     </BehaviorTree>
 </root>

Using scripts:

 <root BTCPP_format="4" >
     <BehaviorTree ID="TreeA">
        <Sequence>
            <GenerateWaypoints waypoints="{waypoints}" />
            <Script code="index := 0" />
            <Repeat num_cycles="3">
              <GetPoseFromIndex queue="{waypoints}"  value="{wp}" index="{index}"/>
              <GetDoubleFromIndex queue="1;2;3"  value="{velocity}" index="{index}" />
              <UseWaypoint waypoint="{wp}" velocity="{velocity}" _post="index += 1" />
            </Repeat>
        </Sequence>
     </BehaviorTree>
 </root>