# IH ivar & menu declaration schema (standalone)

*Shard of mgsv-modding-pack — generated 2026-08-13. 1 files. Provenance is on every entry as `source:path`.*

The complete ivar and menu declaration schema, copied from real IH source, pulled into its own small shard because in the big ih-contract shard it sits thousands of lines deep and models reading through a summarizer never reach it. Fetch THIS when you need to wire an ivar or menu, not the whole contract.

## Verified reference (local) — schemas copied from real IH source

<local>

### `reference_local:ivar-and-menu-declarations.md`

#### Complete ivar and menu declaration schema

**Confidence:** VERIFIED — copied verbatim from Infinite Heaven's own modules
(`ih_kap:.../mod/modules/InfWeather.lua` and siblings). The `ih-framework`
listings show ivar *usage* everywhere but elide the *declaration* bodies; this
fills that gap with real source so a module doesn't have to invent the schema
and risk a silent load failure.

##### registerIvars

Two parts: a name list, then one table per ivar named `this.<ivarName>`.

```lua
this.registerIvars = {
  "weather_forceType",
  "weather_fogDensity",
  "weather_fogType",
}

-- an enum/dropdown ivar
this.weather_forceType = {
  inMission = true,
  settings = { "NONE", "SUNNY", "CLOUDY", "RAINY", "SANDSTORM", "FOGGY" },
  OnChange = OnChangeWeather,
}

-- a numeric slider ivar
this.weather_fogDensity = {
  save = IvarProc.CATEGORY_EXTERNAL,
  range = { min = 0, max = 1.0, increment = 0.01 },
  default = 0.1,
  OnChange = OnChangeWeather,
}

-- an action ivar (a button that runs code, not a stored value)
this.weather_requestTag = {
  settings = this.weatherTags,
  OnActivate = function(self, setting)
    local tag = self.settings[setting + 1]
    WeatherManager.RequestTag(tag, ivars.weather_requestTagInterpTime)
  end,
}
```

##### The field vocabulary

Counts are how many times each field appears across all shipped IH modules — a
high count means it's load-bearing and safe to rely on.

| field | ~uses | meaning |
|---|---|---|
| `range` | 344 | `{min, max, increment}` — makes it a numeric slider |
| `save` | 338 | persistence category, e.g. `IvarProc.CATEGORY_EXTERNAL` |
| `OnChange` | 161 | function called when the value changes |
| `inMission` | 145 | whether it applies/shows during a mission |
| `default` | 124 | initial value |
| `settings` | 103 | array of strings — makes it an enum/dropdown |
| `OnActivate` | 44 | function for an action ivar (self, setting) |
| `category` | 1 | rare grouping field |

An ivar with `range` is a slider; with `settings` it's a dropdown; with
`OnActivate` and no stored value it's a button. Read the live value as
`ivars.<name>`.

##### registerMenus

Same pattern: a name list, then one table per menu.

```lua
this.registerMenus = { "weatherMenu" }

this.weatherMenu = {
  parentRefs = {
    "InfMenuDefs.safeSpaceMenu",
    "InfMenuDefs.inMissionMenu",
    "InfMenuDefs.inDemoMenu",
  },
  options = {
    "InfWeather.weather_forceType",     -- an ivar, by "Module.ivarName"
    "InfWeather.weather_fogDensity",
    "InfWeather.SetSkyParameters",      -- or a function on the module
  },
}
```

`parentRefs` attaches the menu under existing IH menus; `options` lists ivars
(as `"Module.ivarName"`) and module functions in display order.

##### Why this matters

Inventing the ivar schema and getting a field name wrong is a nil-index at load,
which under Fox Engine drops the whole module with no error (see the silent-drop
note in the hard rules). Copy these shapes rather than guessing them.