Filtering the names of rooms printed while in darkness.

In this example, we want the names of rooms to be asterisked out if the player wanders around without the benefit of a candle. We can do this by treating the room names as text, then replacing every letter:

"Blackout"
Tiny Room is a dark room. Absurdly Long-Named Room is a dark room. It is west of Tiny Room.
The Candle Factory is north of Tiny Room. It contains a beeswax candle. The beeswax candle is lit.
Rule for printing the name of a dark room:
   let N be "[location]";
   replace the regular expression "\w" in N with "*";
   say "[N]".
Test me with "w / look / e / n / get candle / s / w".
Test me with "w / look / e / n / get candle / s / w".
**** ****
It is pitch dark, and you can't see a thing.

>(Testing.)

>[1] w

******** ****-***** ****
It is pitch dark, and you can't see a thing.

>[2] look
******** ****-***** ****
It is pitch dark, and you can't see a thing.

>[3] e

**** ****
It is pitch dark, and you can't see a thing.

>[4] n

Candle Factory
You can see a beeswax candle here.

>[5] get candle
Taken.

>[6] s

Tiny Room

>[7] w

Absurdly Long-Named Room

Notice that the hyphen in the Absurdly Long-Named Room does not get replaced. We could replace even that, if we liked, with

   replace the regular expression "\S" in N with "*";

which would catch every character that is not a space.