I’ve now made it so that “reject the player’s command” works as you’d expect in these rules: it shuts down all further processing and returns to the prompt. I also threw together an example for how this might be useful.
"The Riddle of the Labyrinth"
Include Before Processing a Command by Daniel Stelzer.
[We want to interrupt ongoing commands if something dramatic has happened since the last time the player typed something on the keyboard.
We handle this with a flag: it gets set to false whenever the player has the opportunity to type, and set to true whenever dramatic changes happen in the world.
If the flag is true "before processing a command", then, we want to cancel all processing. This is where "reject the player's command" comes in.]
The interruption flag is initially false.
Before reading a command: now the interruption flag is false.
Before processing a command when the interruption flag is true:
say "(Since something dramatic has happened, the remainder of your command---'[player's command]'---has been cut off.)[paragraph break]";
now the interruption flag is false;
reject the player's command.
To interrupt ongoing commands:
now the interruption flag is true.
[Now we contrive a reason why the player would want to type a long sequence of commands on a single line, but might also get interrupted in the process.
This is a sort of maze that was very popular in the early 80s, where every wrong step leads back to the starting location. The intended result is that you need to know the correct path in advance. But what usually happened instead was that players would map it by brute force.]
Definition: a direction (called the way) is viable if the room-or-door (way) from the location is not nothing.
A maze is a kind of room. The printed name of a maze is "Labyrinth". The description of a maze is "Exits lead [list of viable directions]."
Start is a maze. The description of Start is "You've chalked a big X on the floor here to mark your starting point. Exits lead [list of viable directions]." North of Start is Start. East of Start is Maze1. West of Start is Start. South of Start is Start.
Maze1 is a maze. North of Maze1 is Maze2. East of Maze1 is Start. West of Maze1 is Start. South of Maze1 is Start.
Maze2 is a maze. North of Maze2 is Maze3. East of Maze2 is Start. West of Maze2 is Start. South of Maze2 is Start.
Maze3 is a maze. North of Maze3 is Start. East of Maze3 is Maze4. West of Maze3 is Start. South of Maze3 is Start.
Maze4 is a maze. North of Maze4 is Start. East of Maze4 is Maze5. West of Maze4 is Start. South of Maze4 is Start.
Maze5 is a maze. North of Maze5 is Start. East of Maze5 is Start. West of Maze5 is Start. South of Maze5 is Maze6.
Maze6 is a maze. North of Maze6 is Start. East of Maze6 is Start. West of Maze6 is Maze7. South of Maze6 is Start.
Maze7 is a maze. North of Maze7 is Start. East of Maze7 is Start. West of Maze7 is Start. South of Maze7 is Start. Southeast of Maze7 is End.
End is a room. The description of End is "That last passage dropped you in a dead end with no exits. How can you escape now?" Northeast of End is nothing.
[And our source of interruptions!]
The Minotaur is a man.
Instead of jumping in the presence of the Minotaur:
say "You jump on the spot. The Minotaur is startled and flees!";
now the Minotaur is nowhere.
Instead of doing anything in the presence of the Minotaur:
say "The Minotaur charges. The results are unfortunately too gory to describe in text.";
end the story saying "You have died".
Every turn:
if a random chance of 1 in 5 succeeds:
move the Minotaur to the location;
say "The Minotaur lumbers into the room!";
interrupt ongoing commands.
[We don't really want to make the player brute-force the maze.]
The player carries a clue. The description of the clue is "Instead of the traditional spool of thread, the king's daughter gave you this slip of paper. On the front it says: 'E. N. N. E. E. S. W. SE. Then say the magic word.' On the back it says: 'Jumping scares the Minotaur away.'"
[And the final magic word. SAY XYZZY will, by default, map to "answering yourself that xyzzy".]
Instead of answering yourself that a topic:
say "You cry out, '[topic understood]'! But there is no answer."
[The correct path through the maze has drawn out this magic letter on the map.]
Instead of answering yourself that "r" when the location is End:
say "As you call out the magic word, a hidden door swings open in the wall...";
end the story finally saying "But what happens next?".
Results:
Labyrinth
You’ve chalked a big X on the floor here to mark your starting point. Exits lead north, south, east and west.
>i
You are carrying:
a clue
>x clue
Instead of the traditional spool of thread, the king’s daughter gave you this slip of paper. On the front it says: “E. N. N. E. E. S. W. SE. Then say the magic word.” On the back it says: “Jumping scares the Minotaur away.”
>e. n. n. e. e. s. w. se.
Labyrinth
Exits lead north, south, east and west.
Labyrinth
Exits lead north, south, east and west.
Labyrinth
Exits lead north, south, east and west.
Labyrinth
Exits lead north, south, east and west.
The Minotaur lumbers into the room!
(Since something dramatic has happened, the remainder of your command—“e. s. w. se.”—has been cut off.)
>jump
You jump on the spot. The Minotaur is startled and flees!
>e. s. w. se.
Labyrinth
Exits lead north, south, east and west.
The Minotaur lumbers into the room!
(Since something dramatic has happened, the remainder of your command—“s. w. se.”—has been cut off.)
>jump
You jump on the spot. The Minotaur is startled and flees!
>s. w. se.
Labyrinth
Exits lead north, south, east and west.
Labyrinth
Exits lead north, south, southeast, east and west.
End
That last passage dropped you in a dead end with no exits. How can you escape now?
The final command to escape is left as an exercise for the reader.
Before Processing a Command.i7x (16.5 KB)
What I now need is some testing with UGI, to make sure I didn’t break that in the process. Once that’s working, I’ll put this on the Github for public use.
