On occasion the need will arise to attach one object to another. Quite often this can lead to complex situations. If I attach the rope to the chair and walk off carrying the rope, what should happen? Does the rope break, the chair topple over, or the rope constrain me from walking any further? If I attach the red lego brick to the yellow one and pick up the red brick, does it become detached from the yellow one or bring it along with it? If I plug the iron into the wall and attempt to walk away from it, does the plug pull out of the socket, the iron out of my hand, or am I brought up short?
Because the possible permutations are so complex the TADS 3 library can hardly cover every eventuality, but rather than leave the game author with nothing but a few basic verb definitions, it does provide a few classes that at least provide a framework for attaching and detaching objects:
Attachable
NearbyAttachable
Permanent Attachable
PermanentAttachmentChild
PlugAttachable