Olympia PBEM

4.10: Command priority

All orders have a priority of 0-4.

• Permission commands (admit, hostile, etc.) are priority 0.
• Zero time commands[1], and wait, are priority 1.
• move and fly are priority 2.
• The sail command is priority 4.
• All other commands are priority 3.

The order scheduler will first try to start all priority 1 orders. Only when no more priority 1 orders are ready to start will a priority 2 order be started.

In other words, the order scheduler will not start an order at a higher priority when an order may be started at a lower priority.

Orders at the same priority are resolved in location order. If two units in a location are both waiting to start a move order, the first unit in the location will go first.

The above description of order priorities may seem complicated, but the intent is to let players ignore same-day synchronization issues in most cases. Rather that needing wait to guarantee that give happens before move, the lower priority of give makes this happen naturally.

For example, consider three units stacked together, top, mid and bot:

top:    move ec69
        yew

mid:    unstack
        recruit

bot:    recruit

These should be executed in the following order:

mid: unstack                    # unstack is prio-1
top: move ec69                  # move is prio-2
mid: recruit                    # recruit is prio-3

[top and bot arrive at ec69]

top: yew                        # yew is prio-3
bot: recruit                    # recruit is prio-3

The unstack happened first since it's a priority 1 command. The move went second. When top and bot finished moving, there were only priority three commands left, so they ran in location order.

[1] A zero time command is an order which always takes zero time. This does not include an order which may sometimes take zero time. For instance, unstack is always a zero time order. However, recruit is not, even though recruit may terminate immediately under some conditions.