Object
"Everything is an object. Objects have slots. Slots hold data OR behavior." — Dave Ungar, Self: The Power of Simplicity
What Is It?
An Object is anything you can interact with in the adventure world. Keys, lamps, chests, furniture, food, tools — all objects.
Objects are the atoms of the adventure. They:
- Have an identity (id, name, description)
- Advertise their actions (The Sims style)
- Contain state (lit, fuel, uses)
- Inherit from prototypes (Self style)
The Sims Architecture
From Will Wright's SimAntics:
"The intelligence is in the objects, not the characters."
Objects advertise what they can do:
advertisements:
LIGHT:
description: "Light the lamp"
score: 80
guard: "lamp has fuel"
effect: "Darkness retreats"
The character picks from what's advertised. No hardcoded behavior.
Self-Style Prototypes
Objects inherit from prototypes:
inherits:
- skills/objects/light-source.yml
- skills/objects/takeable.yml
A lamp inherits "light-source" behaviors without copying them.
Object Properties
| Property | Purpose |
|----------|---------|
| id | Unique identifier |
| name | Display name |
| type | Category (item, furniture, tool) |
| description | What player sees |
| examine | Detailed look |
| takeable | Can be picked up |
| container | Can hold things |
| contains | What's inside |
| state | Mutable properties |
| advertisements | Available actions |
| inherits | Prototype chain |
State
Objects have mutable state:
state:
lit: false
fuel: 100
uses_remaining: 3
State changes are tracked in YAML. The adventure is the save game.
Simulate — Object Update Loops
THE SIMS INSIGHT: Objects manage their own simulation!
Every object can have a simulate property — a natural language description of what happens each turn. The compiler generates a closure that receives world.
simulate: |
if lit:
consume_fuel(1)
if fuel <= 0:
extinguish()
emit("The lamp sputters and dies!")
This compiles to:
simulate_js: (world) => {
if (world.object.state.lit) {
world.consume_fuel(1);
if (world.object.state.fuel <= 0) {
world.extinguish();
world.emit("The lamp sputters and dies!");
}
}
}
Resilience — The SimCity Zone Pattern
WILL WRIGHT INSIGHT:
"SimCity zones are self-healing. If one tile burns but the center survives, the zone will eventually rebuild."
Simulation functions should be:
1. Robust — Handle Missing Data
// BAD: crashes if state is undefined
if (world.object.state.fuel > 0) { ... }
// GOOD: defensive access
if ((world.object.state?.fuel ?? 0) > 0) { ... }
2. Self-Initializing — Create Default State
simulate: |
first ensure state.lit exists (default false)
ensure state.fuel exists (default 100)
then proceed with normal simulation
The compiled code initializes missing state:
simulate_js: (world) => {
const state = world.object.state ??= {};
state.lit ??= false;
state.fuel ??= 100;
// Now safe to proceed...
}
3. Self-Healing — Recover from Corruption
simulate: |
if fuel is somehow negative, reset to 0
if lit but fuel is 0, extinguish (inconsistent state!)
if broken flag is set but durability is full, clear broken
The compiled code heals invalid states:
simulate_js: (world) => {
const state = world.object.state;
// Heal negative values
state.fuel = Math.max(0, state.fuel);
// Heal inconsistency
if (state.lit && state.fuel <= 0) {
state.lit = false; // Self-heal
world.emit("The lamp was somehow lit without fuel — fixed.");
}
}
The defaults Field
Objects can declare their default state values:
object:
id: brass-lantern
defaults:
lit: false
fuel: 100
durability: 100
simulate: |
ensure all defaults are initialized
...
The runtime merges defaults into state before simulation.
Methods — Named Behaviors
Objects can define named methods that simulate or advertisements can call. Natural language → compiled closures. 1:1 mapping!
methods:
consume_fuel: "reduce fuel by amount, minimum 0"
extinguish: "set lit to false, emit darkness event"
ignite: "set lit to true if fuel > 0"
Compiles to:
methods_js: {
consume_fuel: (world, amount) => {
world.object.state.fuel = Math.max(0, world.object.state.fuel - amount);
},
extinguish: (world) => {
world.object.state.lit = false;
world.emit('DARKNESS');
},
ignite: (world) => {
if (world.object.state.fuel > 0) world.object.state.lit = true;
}
}
The Power of 1:1 Methods
- Method name in natural language = method name in JS/PY
consume_fuel(1)in YAML →world.consume_fuel(1)in JS- Methods compose —
extinguish()can call other methods - Advertisements can call methods in their
effect
The Complete Pattern
Object
├── state (mutable data)
├── simulate (per-turn update)
├── methods (named behaviors)
└── advertisements (player actions)
Advertisements call methods. Simulate calls methods. Methods update state.
Everything flows through compiled closures over world.
Advertisements (Actions)
Each advertisement can have:
LIGHT:
description: "Light the lamp" # What it does
score: 80 # Base attractiveness
score_if: "player is in dark room" # When to boost
guard: "lamp has fuel" # Can you do it?
effect: "Lamp is now lit" # What happens
Natural language fields (score_if, guard, effect) are compiled to JS/PY.
Containers
Containers hold other objects:
container: true
contains:
- brass-key
- old-map
capacity: 10
locked: true
Examples
Simple Item
object:
id: brass-key
name: "Brass Key"
emoji: "🔑"
description: "A heavy brass key."
takeable: true
Lamp with State
object:
id: oil-lamp
name: "Oil Lamp"
emoji: "🪔"
state:
lit: false
fuel: 100
advertisements:
LIGHT:
guard: "fuel > 0 AND not lit"
effect: "The lamp flickers to life."
Locked Chest
object:
id: treasure-chest
name: "Treasure Chest"
container: true
locked: true
contains:
- gold-coins
- magic-ring
advertisements:
UNLOCK:
guard: "player has chest-key"
effect: "The lock clicks open."
Related Skills
- advertisement — How objects announce actions
- room — Where objects live
- buff — Effects objects can grant
- prototype — Inheritance system
Protocol Symbol
SIMANTICS — The Sims behavioral architecture