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§12.9. Check, carry out, report

The normal behaviour of an action is specified by its three associated rulebooks - check, carry out and report. In the case of our "photographing" example, these rulebooks will be:

Check photographing. Here, for instance, we need to verify that the player has the camera. If any of our checks fail, we should say why and stop the action. If they succeed, we say nothing.

Carry out photographing. At this stage no further checking is needed (or allowed): the action now definitively takes place. At this point we might, for instance, deduct one from the number of exposures left on the film in the camera, or award the player points for capturing something interesting for posterity. But we should say nothing.

Report photographing. At this stage no further activity is needed (or allowed): whatever effect the action had, it has happened and is now over. All we can do is to say what has taken place.

So far we have not really gone into the business of what rulebooks are, and we don't do so here either - suffice to say that we can now create whatever rules we need:

A check photographing rule:
    if the camera is not carried:
        say "You can hardly photograph without a camera, now can you?" instead.

In fact, writing "a check photographing rule" is over-formal. We can more simply label our rules like so:

Check photographing:
    if we have photographed the noun:
        say "You've already snapped [the noun]." instead.

Report photographing: say "Click!"

For the sake of brevity, photography has no interesting consequence (no points to be won, no film to use up), so there are no carry out rules here. Note the way we used the word "instead" once again to stop actions in their tracks.

We can continue to add rules at any point, and a classic thing that happens when testing a new work is that the designer realises there is a case which has not been thought of:

Check photographing:
    if the noun is the camera:
        say "That would require some sort of contraption with mirrors." instead.

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*ExampleThe Dark Ages Revisited
An electric light kind of device which becomes lit when switched on and dark when switched off.

A CUT [something] WITH [something] command which acts differently on different types of objects.

***ExampleDelicious, Delicious Rocks
Adding a "sanity-check" stage to decide whether an action makes any sense, which occurs before any before rules, implicit taking, or check rules.

Creating a stage after the report stage of an action, during which other characters may observe and react.