Monster Ring Patch v2.1

Details

Vanilla Nethack (as of version 3.4.3) does not let non-player monsters put on rings, or benefit from their effects. In fact, non-tame monsters won't even pick up rings they find lying around the dungeon. By allowing monsters to pick up and use rings, we allow for new, more evil player-monster interactions.

This patch allows monsters to pick up and use certain kinds of rings. The rings affected by the patch are:

• Invisibility. Shopkeepers and uniques will not wear this ring, and it is not preferred when the player can see invisible.
• Teleportation. Shopkeepers and uniques will not wear this ring. It confers the same teleportation effect as being a tengu.
• Teleport control.
• See invisible.
• Regeneration.
• Protection.
• Fire resistance.
• Cold resistance.
• Shock resistance.
• Poison resistance.
• Increase accuracy.
• Increase damage.
• Slow digestion. Wearing this ring causes the same effect as an amulet of life saving, when swallowed by a player in the form of a purple worm. Monsters will only prefer this ring when the player is polymorphed into a digesting monster (purple worm, trapper, lurker above). It has no other in-game effect. (One interesting interaction: It is possible to attempt to eat one of the Riders while it is wearing a ring of slow digestion. You'll immediately spit it out with no ill effects.)
• Adornment. Only succubi care about this ring.

Changelog

• Version 1.1. Initial release.
• Version 1.2.
  • Generalized "purple worm" to "digester" in a few places.
  • Added monster-on-monster effects of slow digestion.
  • Monsters prefer fire resistance when you're wielding Fire Brand, and cold resistance when you're wielding Frost Brand.
  • Monsters' rings fall off with their gloves, when they're polymorphed into handless or tiny creatures.
  • Bugfix: Monsters can put on rings "over" gloves or other rings.
  • Bugfix: Uniques and shopkeepers can wear rings of regeneration.
• Version 1.3.
  • Changed one more "purple worm" to "digester."
  • Friendly monsters will not equip a ring of invisibility unless you can see invisible.
  • Bugfix: Test for shopkeepers correctly; previous code had been testing for "covetous" monsters such as the Wizard.
• Version 1.4.
  • Bugfix: Fixed total misunderstanding of tele_restrict causing spurious messages on non-teleport levels.
• L's improved monring patch, based on my version 1.4:
  • Monsters can wear two rings, not just one.
  • Monsters can wear and benefit from rings of see invisible, teleport control, increase accuracy, and increase damage.
  • Monsters can now gain these attributes from held artifacts as well.
  • Player-monsters can now be generated with rings.
  • Monsters prefer fire, cold, shock, or poison resistance when you're polymorphed into a form with one of those attacks.
  • Monsters wearing rings of teleport jump much less frequently than in my version: 1 time in 85, instead of 1 in 5.
  • Behind-the-scenes code changes for extensibility.
• Version 2.1 (February 2007).
  • Started afresh using L's codebase. The following changes are with respect to L's patch.
  • Unique monsters will wear rings of teleport control.
  • Teleportation activates once every 10 turns, on average, instead of once every 85 turns (as the player's would). This is to make things more interesting.
  • Succubi prefer rings of adornment (with positive enchantment) to any other ring.
  • Succubi will wear the rings they steal, and will not steal rings they do not intend to wear.
  • Monsters >XL12 and magic-users >XL8 have intrinsic teleport control.
  • Teleporting monsters will make a saving throw when drowning, just like the player.
  • Weak monsters will wear rings of polymorph, just as they will jump onto polymorph traps. However, rings of polymorph don't actually confer polymorphitis yet.
  • Player-monsters can be generated with rings of regeneration or see invisible. They will not get two of the same ring.
  • A few more places check mon_prop(SEE_INVIS) instead of perceives().
  • Cursed weapons should weld to monsters' hands in the same way, and with the same effects, as they do to players'; inconsistencies have been fixed in bullwhip-applying and nymph-stealing code (see known bug 343-257).

Future directions

More monsters should be generated with rings; in particular, I'm thinking that hobbits should get an extra chance at gold rings (a Lord of the Rings reference), and nymphs should get rings of adornment.

Rings of levitation should be implemented. I'm not sure how big a change that would be. At the moment, monster levitation is not implemented at all (but flying is); that's open bug C343-184.

It would be nice to add polymorph, free action, searching, and polymorph control to the list of rings available for monsters' use. (The problem with polymorph control: There would have to be logic dictating what a gnome, say, would do with a controlled polymorph. It might lead to a lot of titans wandering around DLvl 4!)

Also reasonable, but much less interesting in terms of gameplay, would be gain strength, gain constitution, and possibly stealth. The remaining rings, among them protection from shape changers, warning, and conflict, don't have any obvious application to non-player monsters.

In vanilla Nethack 3.4.3, digesting a monster leaves its possessions neatly in a heap on the floor. It might be be more sensible to destroy (some of?) those items, as if they had been eaten by the player, with the associated intrinsic gains. That might be too powerful, though; I'm not sure. Also, digestion behavior is tangential to the main point of this patch, which is to allow monsters to use rings.