# editorPanel
A dock tab in the editor, as an asset. A `<name>.editorPanel/` folder carries an
`init.luau` that returns the tab's spec:
```luau
local edui = require("@builtin::~edui.framework")
return {
title = "My Tab", -- the tab's label (`label` is accepted too)
order = 60, -- sort position in the menu
dock = "bottom", -- seeds the FIRST arrangement: left | right | bottom | center
menu = "scene", -- which top-bar menu lists it; an unknown name creates that menu
startClosed = true, -- registered closed; opened from the menu
build = function() -- the tab's body, called again whenever it should change
return edui.panel{ body = edui.text{ text = "hello" } }
end,
}
```
`build` is the only required field. The tab id defaults to the folder stem
(`myTab.editorPanel` → `myTab`); an explicit `id` overrides it, and a duplicate
id replaces the prior registration. An init may return a LIST of specs when one
asset carries several tabs — a spec this registration no longer declares has its
tab taken down.
The spec is forwarded whole to `edui.shell.addPanel`, so anything the shell
accepts (`badge`, `badgeColor`, …) works here; `man edui.shell` is its contract.
`build` may return `nil` to mean "nothing changed, keep what is drawn" — the
shell rebuilds open tabs on a timer, and a panel that re-publishes an identical
tree pays for it. Only the ACTIVE tab of a dock leaf is rebuilt at all.
An `init.luau` that fails to load does not break the editor: its tab comes up
carrying the failure — the path and the error, selectable — so a panel that will
not compile says so where you would look for it.
Every instance of this type becomes a tab: the ones in the open world, and the
ones the built-in library ships, on the same terms.
Adding a tab to a project is creating a new `editorPanel` asset: it comes from
the template above and registers its tab at once, wherever under `/source` it
was made (`editorPanels/` is the type's conventional folder). Editing the
`init.luau` re-registers the tab, deleting the folder removes it. Nothing
registers panels by name anywhere.
`guides { path = "editor/edui/edui" }` — the guide beside this type, inside
the edui package — covers the build model, where panel state lives, and the
`edui.*` surface a body draws with.
## In the Inspector
Panels: each panel id this file registers (`panelRef:panelIds()`), whether it is open, an **Open** action for it, and **Open** for the source. A file whose init.luau does not load says why.
# edui (module)
The editor UI framework, built on the CSS-parity `ui.*` surface. `edui` is
**editor-only** — gameplay and normal UI author raw `ui.*` widget trees
(`{ type, style, props, children }`) and need no framework. `edui` provides the
one thing a framework earns its keep for: editor chrome — a reactive app, a
dock shell, and chrome primitives (panels, trees, toolbars, inspector rows,
context menus, drag-and-drop). It replaces the deprecated `zui` for the editor.
## The reactive core (`edui.app`)
`ui.*` dispatches interaction through **string callback ids** — a widget
carries `props.onClick = "<id>"`, and the screen's registered env receives
`onCallback(id, data)`. Closures can't cross the FFI boundary, so raw `ui.*`
makes you manage those ids by hand.
An `edui` **app** hides that. During a build it allocates an id per closure and
records id→closure; its single `onCallback` looks the id up, calls the closure,
and rebuilds:
```lua
local edui = require("@builtin::modules.edui")
local count = 0
local app = edui.createApp("counter", { layer = editorMask })
app:mount(function(a)
return {
type = "vertical",
children = {
{ type = "label", props = { text = "count: " .. count } },
{ type = "button", props = { text = "+1",
onClick = a:cb(function() count += 1 end, "inc") } },
},
}
end)
```
- `app:cb(closure, key?)` — allocate a callback id for `closure`. Pass a stable
`key` so the id survives rebuilds (required for focus / drag / `ui.widgetState`).
- `app:dispatch(id, data)` — what the broadcast calls; routes id→closure and
rebuilds. Returns whether this app owned the id.
- `app:markDirty()` — request a rebuild (coalesced during an in-progress build).
- `app:rebuild()` / `app:mount(fn)` / `app:unmount()` — lifecycle.
- `edui.current()` — the app whose builder is running (the primitives use it so
you don't thread the app through every call).
Builder and handler errors are logged, never thrown — one bad build never
wedges the editor.
# editorSelection
Named selection scopes for the editor. A scope is an independently
tracked, ordered set of typed refs plus a primary (the last ref added
or clicked). Distinct scopes never clobber each other, so viewport,
outliner, inspector and asset browser share one answer to "what is
selected" per kind.
A ref is `{ kind: string, id: string }` — a stable id, never a display
string, so rename/move never invalidates a selection.
## Exports
- `M.scope(name) -> Scope` — get/create a named scope handle.
- `M.set(scope, refs)` — replace refs in order; primary becomes the last.
- `M.get(scope) -> { Ref }` — refs in click order (fresh array).
- `M.primary(scope) -> Ref?` — last-clicked ref, or nil.
- `M.clear(scope)` — empty a scope.
- `M.toggle(scope, ref)` — add if absent, remove if present.
- `M.add(scope, refs)` — add each ref not already present; primary becomes the last added.
- `M.remove(scope, refs)` — remove each of `refs`; primary becomes the last remaining or nil.
- `M.contains(scope, ref) -> boolean` — membership by `(kind, id)`.
- `M.count(scope) -> number` — the scope's selection size.
- `M.subscribe(scope, fn) -> handle` / `M.unsubscribe(scope, handle) -> boolean`.
- `M.context() -> { scope, refs, primary }` — last-focused scope, for command ctx.
## Usage
```luau
local Selection = require("@builtin::modules.api.editor.selection")
local scope = Selection.scope("entity")
Selection.set(scope, { { kind = "entity", id = "player_1" } })
Selection.subscribe(scope, function() refreshInspector() end)
```
## Notes
- State lives in a fixed `_G` slot, seeded pre-seal by the boot chain
(`prelude.luau`); it survives hot-reload and edit↔play flips. Mutations
after boot write into nested tables only.
- `set` / `toggle` / `clear` mark their scope as last-focused, which drives
`context()` and therefore which scope commands act on.
- The service holds the editor's selection state in Luau. Refs handed back by
`get` / `primary` / `context` are copies, so a caller can hold or mutate them
without touching internal state.
# assetBrowser
<!-- zero:scaffolded-readme -->
<!-- Replace the line below with what this module provides and who
consumes it, then delete both comment lines. -->
TODO: describe this module.
# entityOps
Operate on scene entities — spawn, instantiate content, change state,
swap, and navigate the hierarchy. Every tool resolves targets by entity
**name or id** (single, a list, or the records `scene.find` returns) or
by a **`scene.find` query** (`{ name = { "wheel" } }`,
`{ component = { "Light" } }`, `{ under = { "car" } }`) that names a
selection without looking it up first, and asset inputs by a name / path
/ identity string that the tool resolves and reports back canonically —
so the caller never needs to know an asset's exact identity up front.
Finding and reading entities is the `scene` toolbox (`scene.find`,
`scene.tree`, `scene.summary`); this toolbox is the operating surface.
## Spawn + instantiate
- **spawn** — spawn entities from a template: name the components they
carry and their field values, plus a transform. Authored (serializing)
components only. Pass a `{ defaults, items }` list to spawn MANY in one
call with shared defaults and per-item overrides — a six-walled room is
one call, not six — validated whole before any entity is created.
- **fromAsset** — instantiate an existing asset (bundle / avatar / mesh /
material / texture, or anything with an `:instantiate()`): resolves a
name/path/identity string, dispatches by category, and reports the
canonical asset it hit. Controls the live `link` and `synced` flags.
## State + hierarchy
- **modify** — delete / enable / disable / internal / temporary /
reparent / rename, over one or many entities.
- **swap** — replace an entity with another entity that already exists in
the scene (moves it into the target's slot).
- **addComponents** — attach component(s) with setup data to one or many
entities; `create` spawns missing ones.
- **removeComponents** — detach component(s) from one or many entities,
reporting per entity what was `removed` and what was `absent`.
- **component** — inspect a component TYPE's schema: its public fields
(name + type + current value), methods, and lifecycle hooks — so you
set fields that exist instead of guessing. Reach for it before
`addComponents` / `spawn`.
- **roots** — find the root ancestor of one or many entities.
## Transform + copy
- **transform** — move, rotate and scale: absolute sets, relative
offset / rotate / scaleBy, and grid snapping. With no ops it is a pure
read of the current transform.
- **duplicate** — copy entities, one at a time or as a numbered run
stepped along an accumulating `offset`.
## Addressing a set you built
Every tool here resolves targets by **query** as well as by name or id, so
a set can be operated on without retaining a single id. Tag the set as you
build it, then address it by that tag:
```lua
-- Build the set in one call, tagged.
entityOps.spawn({
defaults = { components = { Model = { model = "cube" } },
attributes = { group = "roomA" } },
items = { { name = "wall_n", position = { 0, 1, -2 } },
{ name = "wall_s", position = { 0, 1, 2 } } },
})
local set = { attribute = { name = "group", value = "roomA" } }
entityOps.transform(set, { offset = { 0, 5, 0 } }) -- move the whole set
renderLayer.set(set, "shell") -- re-layer the whole set
entityOps.modify(set, { delete = true }) -- remove the whole set
```
The tag is an ordinary entity attribute, so it persists with the scene and
is as much a part of the content as a name is.
To see what is already present rather than what you made, `scene.find`
with no search axis returns the whole live population, and
`include = { "transform", "componentValues", "attributes" }` annotates
each hit — one call, no follow-up per entity.
# assetType (asset type)
An asset type says what a kind of asset is: the files an asset of the kind is
made of, the code that gives it behaviour, the interface a person uses to work
with it, and how it is found, pictured and checked. A `<typename>.assetType/`
folder declares a type called `<typename>`, and every `<name>.<typename>/`
folder is an asset of it. `assetType` is itself a type, so a type is an asset
like any other: it is created, versioned, installed and contributed the same way.
## Making a type
`asset.create("assetType", "<typename>")` scaffolds a type. The type registers
the moment its folder is written, anywhere under `/zero/source/`, and from then
on `<name>.<typename>/` folders are its assets. An asset of a type that is not
registered yet is not an asset, so make the type first.
A type folder is a root: `~.x` in any file inside it names the type's own `x`,
wherever the type is installed. Keep the type's whole implementation inside its
folder and reach it that way.
What a type folder must hold is set by this type's own `type.yaml`, the same way
every type's `type.yaml` sets what its assets hold. `asset.validate` on a type
reports anything missing, and the scaffold produces a folder that passes.
## What sets your type's schema (`type.yaml`)
`type.yaml` is the structural contract every asset of the type is checked
against. The keys below are the ones the engine reads; a key not listed here is
ignored.
| Key | What it controls |
|---|---|
| `suffix` | The folder suffix of the type's assets. Defaults to `.<typename>`. |
| `primary` | The file or files that are the asset's content: what the asset resolves to when it is used. |
| `entry_files`, `primary_aliases` | Further files that load as the asset or share its identity. |
| `is_container` | Whether the suffix stays in the identities of what the asset holds. |
| `is_opaque_walker` | Whether a walk of the tree stops at the asset and registers only its primary. |
| `plural_dir`, `classify_exts` | Loose files in a folder of this name, or with these extensions, are assets of the type. |
| `is_text_default` | Whether the asset's files are text unless stated otherwise. |
| `broadcasts_subassets` | Whether assets nested inside an asset of the type are found by their own short name. |
| `root` | `true` makes every asset of the type a root, so `~.x` inside one names that asset's own `x`. |
| `contract_ref: { field, category }` | A key of the primary file that names another asset the asset is built on. |
| `files: { required, optional }` | The files an asset holds (below). |
| `allow_unlisted` | `false` reports every file the type does not declare. |
| `aliases_from: [{ file, key }]` | Further names an asset answers to, read from its own files. |
| `settings:` | Typed per-asset settings (below). |
| `inspector:` | The interface people use for the type and its assets (below). |
| `preview:` | How an asset is pictured (below). |
| `references:` | Names of other assets the type's files carry (below). |
| `indexing:` | What search reads for each asset (below). |
| `describe:` | How a missing description is generated (below). |
### The files an asset holds
Each entry under `files.required` or `files.optional` is
`{ path, kind: file | folder, one_of_group?, content? }`. `*` in a path matches
within one segment. Entries that share a `one_of_group` are satisfied by any one
of them. `content` lists checks on the file's bytes:
| Check | Passes when |
|---|---|
| `non_empty` | the file has content |
| `json_field { key, type?, non_empty?, accept? }` | the JSON holds the key (a dotted path) with that shape |
| `yaml_field { key, type?, non_empty?, accept? }` | the same for YAML |
| `described { keys?, headings?, message? }` | the file says what the asset is (see "Ask your assets to say what they are") |
Each check takes a `message`, which is what the author is told when it fails.
### Settings
`settings: { values, schema: { type | instance, export? } }` gives every asset
typed settings. `values` names the file an asset's values live in; `schema.type`
declares one schema for the whole type, and `schema.instance` names a file each
asset declares its own in. `asset.create` writes the resolved values, and a write
to the values file reaches `onChange` with what changed.
## The human side (`inspector.luau`)
A type is used by people through its Inspector, and without one the type is
usable only from code. The Inspector is the type's interface for a person: for a
procedural graph it is the graph editor, for a kit it is the tracking view of
what the kit holds and what is still missing. Writing it is part of writing the
type.
`inspector: { type, instance? }` in `type.yaml` names the files. `type` is the
interface for the type itself and for its assets; `instance` names a file an
asset may ship to add its own. Each returns:
```luau
return {
sections = { { id = "graph", title = "Graph", build = function(ctx) ... end } },
replace = { contents = { ... } }, -- replace a default section by id
order = { "graph", "contents" }, -- section order
}
```
`build(ctx)` receives the asset and builds the section. A section's `title`, and
the text its rows carry, is a string or an `i18n.text` value read from a catalog
(`i18n.text("inspectors.mesh.title")`), which follows the editor's language. `asset.create("assetType",
...)` scaffolds a working `inspector.luau` to start from. `asset.validate` on a
type that names no inspector, or names one that does not load, reports it.
## Say what your type is for (`about.yaml`)
Every type carries an `about.yaml` that says what the type is for, in three
plain-language texts:
```yaml
intent: "Sets the typeface of the text in your game: UI, labels, signs and 3D lettering."
function: "A font, from a TTF, OTF or WOFF file, made available to all of Zero's text, including 3D text."
usage: "You choose it by name for your UI or your text, and the text appears in that typeface."
```
- **`intent`** is what the type is for in someone's game, in the words a game maker uses. Up to 800 bytes.
- **`function`** is how it works today: what an asset of it is made of and what the engine does with it. Up to 1500 bytes.
- **`usage`** is what a person or an agent does with one. Up to 1200 bytes.
Write about the type as a whole, not one asset of it, and say what it does now.
Agents read these texts to learn when to reach for the type and how; people
searching find the type by them. The scaffold starts each text with
`[[describe]]` and a note on what to write; a text that still starts that way
counts as not written. `services describe` can write them.
They show up in `asset.inspect` as `detail.about`, in
`assetTypeRef:getAbout()`, at the end of the type's `types/<typename>` guide,
and at the top of the type's Inspector.
## Ask your assets to say what they are
A type can require each asset to carry a description: a file, written by the
author or generated, saying what the asset is and what it is for. Declare it with
a `described` check:
```yaml
files:
required:
- path: "README.md"
kind: "file"
content:
- { check: "described", message: "Say what this widget is for and where it goes." }
```
A file that is missing, empty or still has a line starting with `[[describe]]`
fails the check, and so does a YAML file whose named `keys` are missing or over
their `max_bytes`, or a Markdown file missing a named heading. `asset.validate`
names the asset, and a push that carries it is refused with `message`.
`services describe` finds such assets and writes their descriptions.
`describe:` steers what is generated:
```yaml
describe:
guidance: "Say what the widget shows, what input it reacts to, and where it fits in a UI."
examples:
- "<identity of an asset of this type whose description reads well>"
```
An example is an asset of your type whose description is a true, written one,
never a placeholder and never the asset being described; with none, leave
`examples` empty. A type whose assets the model cannot perceive (a sound, a
motion) says so in `guidance`, and the description is drawn only from what the
asset's own files state.
Start the file unwritten in your `template/`: a heading and one line starting
with `[[describe]]`, never example content, which every new asset would carry
verbatim. A type whose assets say what they are through their own content (a
mesh, a texture) declares no check.
## The type's code (`behavior.luau`)
`behavior.luau` returns one table. These are the keys the engine reads from it;
anything else on the table is the type's own.
### What the type's assets can do
| Key | Shape | What the engine does with it |
|---|---|---|
| `ref` | `{ [name] = function(self, ...) }` | Every function becomes a method on every asset of the type: `ref:name(...)`. |
| `modules` | `{ [name] = require(".x") }` | Code the type's assets reach with `asset.containing(__FILE__).modules.<name>`. |
| `events` | an events schema | Events an asset fires. Readers subscribe through `ref.events.<name>:connect(...)`; the type fires them. |
| `refShapes` | `{ [method] = function(self) -> (typeExpr, source?) }` | The result type of a `ref` method for one particular asset (below). |
| `namePattern` | a Lua pattern | The names `asset.create` accepts for the type's assets. Default `^[A-Za-z][A-Za-z0-9_]*$`. |
| `derive` | `{ output, module, compute, fingerprint, matches?, required?, timeout? }` | A file computed from the asset when it is committed; a `required` one holds the commit until it lands. |
Some `ref` names mean the same for every type, and the engine calls them:
- **`instantiate(self, target?, opts?) -> (root, idMap)`**: puts the asset in a scene. Defining it is what makes the type scene-instantiable. Its return is a contract (below).
- **`inspect(self) -> detail`**: what `asset.inspect` reports for the asset beyond the common record (below).
- **`preview(self, opts)`**: renders the asset's picture; it wins over the type's `preview:` recipe.
- **`previewMaterial(self) -> { material }`**: the material a `surface` preview paints.
- **`saveDefinition(self)`**: writes the asset's in-memory edits back to its files in edit mode.
Some names are answered for every asset before the type is asked, so a `ref`
entry of the same name is never reached: `getSource`, `getBytes`, `getText`,
`exists`, `deps`, `canInstantiate`, `canPreview`, `preview` (which calls yours
when you define one), `meta`, `runtime`, `events`, `typeRef`, `modules`, and the
residency flags `has_backing_asset`, `has_runtime_changes`, `cpu_resident`,
`gpu_resident`.
### When the engine calls the type
| Hook | Signature | When it runs |
|---|---|---|
| `onCreate` | `(name, opts) -> { [path] = contents }` | On `asset.create`. Returns the files of the new asset, laid over the type's `template/`. Annotate `opts`: its type is the schema `asset.create` checks the caller's arguments against. A `""` key writes a single loose file. |
| `onReplace` | `(dest, files) -> files` | On an `asset.create` over an asset already at `dest`, after `onCreate`, so what the author added can be carried into the replacement. |
| `onRegister` | `(self)` | Once per asset, when it first registers: when the world loads, on a live `asset.create`, and when an asset arrives later (installed, pulled, synced). This is what makes an asset take effect the moment it is written. |
| `onChange` | `(ref, change)` | On every write to a file inside an asset of the type. `change` is `{ path, asset, type, kind, origin }`, plus `settings` and `settingsChanged` for a write to the settings values file; `kind` is `edited` or `seeded`, `origin` is `local` or `remote`. Filter on `change.path`. Writes to one asset arrive in order, each after the hook for the one before has finished, and the hook may wait on what it reads. A write the hook makes inside its own asset arrives later like any other, so keep the hook convergent. |
| `onDependencyChange` | `(ref, change)` | When a module the asset's code requires is re-run, or a name the asset carries starts resolving. `change.kind` is `dependency`. |
| `onDelete` | `(ref)` | When an asset of the type leaves the world: deleted, or the world it is in is swapped away. |
| `validate` | `(ref) -> { { code, message, severity?, path? } }` | On `asset.validate`, after the `type.yaml` checks, for the type's own rules. `severity` defaults to `error`. Runs on every push, so a type's rules hold at publish. A hook that fails reports `validate.hook_failed`. |
### Settings hooks
| Hook | When it runs |
|---|---|
| `settingsDefaults(name, opts, asked) -> table` | Once per `asset.create`, for values the schema's defaults do not give. |
| `settingsCorrections(values, name, opts) -> (corrections?, reasons?)` | On every settings write. A correction to a field the writer named refuses the write, giving the reason. |
| `settingsDerivedDefaults(values, explicit, changed)` | On a settings write, for fields derived from others. |
| `normalizeSettings(values, stored?)` | On every read and write, to map an earlier spelling of a field to the current one. |
| `settingsHealed(values, stored)` | On a read, to repair stored values. |
| `settingsSchemaProblem(schema, ref) -> string?` | When an asset's own schema is read; a returned string refuses the schema. |
`creationInputs` (`{ [opt] = true | selectorOpt }`) names `asset.create` options
that are inputs to the type rather than settings.
### Reloading
An edit to `behavior.luau` reaches existing assets with no restart.
## How an asset is pictured (`preview:`)
| `kind` | The picture is | The type provides |
|---|---|---|
| `instantiate` | the asset placed in the preview studio through its `instantiate` | `ref.instantiate` |
| `image` | a file the asset holds, fitted to the frame | `source: { files }`, the candidate files in order |
| `surface` | the asset painted on a mesh | `mesh`, and `ref.previewMaterial` |
| `custom` | whatever `ref.preview` returns | `ref.preview` |
```yaml
preview:
kind: surface
mesh: sphere
```
`angle: [yaw, pitch]` turns the camera. The studio owns the light, the backdrop
and the framing, so an asset pictures the same in every world. A type with no
`preview:` that defines `instantiate` still answers `ref:preview()`.
A picture is rendered when something asks to view it (the editor showing the
asset, `ref:preview()`), when previews are generated on request
(`assets.generatePreviews`), and when the asset is staged. An edit alone
renders nothing. The picture records what it was made
from, so a stale one is told from a current one.
## The names your type's assets hold (`references:`)
Where your type's own format or API carries the name of another asset, declare
it here:
```yaml
references:
keys: # a top-level key of the type's files that holds a name, or a table of them
- { key: "shader", type: "shader" }
args: # an argument of a call, counting from 1
- { call: "g:node", position: 2, type: "procNode" }
fields: # a field of the options table a call takes
- { call: "fx.beam", field: "material", type: "material" }
```
`type` is the category the name resolves in. `asset.declareReferenceKey`,
`asset.declareReferenceArg` and `asset.declareReferenceField` declare the same
from a script.
## What search reads (`indexing:`)
`indexing:` is how assets are found. Search reaches an asset only through what
its type's `indexing:` names, and adds nothing of its own. That includes you: an
asset indexed badly is one you cannot find later, when you are making something
else and need it. A type whose assets are never looked for says `indexing: none`.
```yaml
indexing:
data: # text, read from the asset's files
- role: identity
extractor: verbatim
source: { file: "README.md" }
- role: interface
extractor: symbols
source: { files: ["init.luau"] }
- role: implementation
extractor: verbatim
source: { files: ["init.luau"] }
content: # the picture
- role: identity
modality: image
source: { file: "preview.png" }
facets: # what a query filters and re-ranks by
file: ".metadata"
rigged: { type: bool, from: { components: { contains: SkinnedModel } } }
roughness: { type: number, filter: range, from: { file: "mat.yaml", field: "floats.roughness" } }
```
**Roles.** Each `data` and `content` entry has a `role`, and a query matches in
two slots:
- **`identity`**: what an asset is. For anything you look at, the picture; for anything else, the text that says what it is.
- **`capability`**: what it does and how it is made. `interface` (the signatures or shape a caller uses) and `implementation` (the body) both count as capability, and a type with code usually declares both.
Ask what a person would recognise an asset of the type by, and what it does, and
point each role at the file that says it. For text, that is the asset's
description: the file your template starts with a `[[describe]]` block, which the
author writes or `services describe` fills in (see "Ask your assets to say what
they are").
**`data`.** `extractor: verbatim` embeds a file's text as it is; `symbols` embeds
the declared signatures of code. `source` is `{ file }` or `{ files: [...] }`.
Never index a file name (`source: { field: name }`): one
or two words carry nothing to match.
**`content`.** `modality: image` embeds the picture itself, so a text query
matches what the asset looks like. A type whose assets are looked at makes the
picture its identity.
**`facets`.** What a query narrows and re-ranks the matches by. `file` is embedded
whole, so keys nobody declared in it are still found. Each further key is
computed for every asset and states a value for every one, including `false`: a
file can imply "not rigged" but never say it, and a query separates rigged from
unrigged only because the unrigged ones say `rigged: false`. A key is
`{ type: bool | number | enum, filter?: range, from }`, where `from` is
`{ file, field }` (a field of one of the asset's files, dotted for nesting),
`{ metadata: key }`, or `{ components: { contains | any_outside } }` (what the
asset's entities carry).
## What blocks a push
A push checks every asset it carries against its type. These refuse it:
- a required file that is missing, a `content` check that fails, a `described` file not written yet;
- an error from the type's `validate`.
Unlisted files and warnings do not. A `described` file blocks only a push that
changes the asset. When a push is refused, the message names each asset and what
it lacks. `world.publishBlockers()` and `zm status` read the same list without
pushing.
## Typing a result from the asset (`refShapes`)
A `ref` method whose result depends on the asset (one entry per child folder, per
row of a config, per control a map declares) can only be annotated as
`{ [string]: Thing }`, which accepts any key. `refShapes` states the result for
each asset instead: a function returning a Luau type expression for that asset,
and the module whose types the expression uses. Read the asset; never run it.
```lua
-- inputMap.assetType/behavior.luau
M.refShapes = {
activate = function(self): (string, string)
local names = {}
for _, control in ipairs(M.ref.controls(self)) do
table.insert(names, control.name .. ": Handle")
end
if #names == 0 then return "", "" end
return "{ " .. table.concat(names, ", ") .. " }", "@builtin::modules.zinput.scheme"
end,
}
```
With it, `map.jump:onPressed(fn)` is checked and `map.noexisting` is reported.
A per-asset type applies where the call site names which asset: a component
field whose default names it, or an annotation `AssetRef<"inputMap", "<identity>">`.
`asset.resolve(name, category)` carries only the category, and a name computed
at runtime carries nothing, so calls on those keep the declared return. The type
belongs to the call's result: index it there, or bind what you need from it
there, and the names stay checked.
`require("@builtin::assetTypes.assetType.shared.refShapes").published()` shows
what was published: `categories` (each type's method surface) and `returns`
(per-asset results by identity, then method). An identity missing from
`returns` was never published. Results are recomputed when an asset is written;
at most 64 assets of one type are read.
## Putting an asset in a scene (`ref.instantiate`)
A caller writes one piece of code against every instantiable type, so what
`instantiate` returns is fixed:
```lua
local Instantiable = require("@builtin::assetTypes.assetType.shared.instantiable")
M.ref = {
instantiate = function(self, target, opts)
local root = Instantiable.root(self, target, opts)
-- compose the asset under `root`, now
return Instantiable.result(self, root, idMap)
end,
}
```
**In.** `target` is the entity the asset lands under, or onto for a hierarchy
type; with none, the type spawns a new root. `position`, `rotation` (three
numbers in degrees, or a quaternion), `scale`, `name` and `temporary` mean the
same for every type: `Instantiable.root` applies them to a root you make,
`Instantiable.place` to one you adopt. Document any options of your own in the
hook's `--!arg` docs.
**Out.** `(root, idMap)`. `root` is the composed root, live when you return:
build synchronously, never defer to a component's `awake`. `idMap` maps each
original id to the spawned one, so a component that composes the asset again on
every load can pass it back in and keep references into the composition. Every
call goes through `Instantiable.result`, which refuses a root that is not live
and turns a missing `idMap` into `{}`.
## Inspecting an asset (`ref.inspect`)
`asset.inspect(ref)` builds a record every asset shares (`identity`, `name`,
`guid`, `source`, `typeName`, `typeDefinitionPath`, `scope`, `origin`,
`description`, `tags`), then calls `ref.inspect(self)` for the type's own
`detail`:
```lua
M.ref = {
inspect = function(self)
-- read the asset's own files, never runtime state: inspect works on an asset
-- that has not been compiled, uploaded or registered
return { --[[ what makes this asset what it is ]] }
end,
}
```
Without it, the record is the shared part alone, and an agent inspecting the
asset learns nothing of what it is. A hook that raises leaves `detail` empty and
sets `record.warning`.
## Discovery
- `asset.list("assetType")`: every registered type.
- `asset.inspect("<typename>")`: the type, its README and its `about.yaml` texts.
- `asset.resolve("<typename>", "assetType")`: the type itself.
# edui
The editor UI framework, on the CSS-parity `ui.*` surface. An editor-only
toolkit: panels author closures instead of callback ids, a dock shell over
`ui.*` native docking, and typed editor-chrome primitives. Gameplay and normal
world UI author raw `ui.*` trees and need none of this.
**`edui.guide` beside this file is how to use it** — creating a panel, the spec
it returns, how a panel is drawn and redrawn, the whole widget vocabulary, and
how a panel reaches the selection and the dock.
## What installs
- **`framework`** — everything under one table. From outside the package,
`require("@builtin::~edui.framework")`; inside it, `require("~.framework")`.
It carries `app`, `widgets`, `shell`, `topbar`, `query`, `fileDialog`,
`worldDialog`, `stats`, and the chrome primitives flat (`panel`, `tree`,
`field`, `section`, `text`, `button`, `menu`, …).
- **`app`** — maps a panel's closures to `ui.*` callback ids, dispatches to
them, and coalesces redraws.
- **`widgets`** — the primitives, plus the typed inspector layer
(`widgets.tree`, `widgets.fields`, `widgets.controls`).
- **`inspector`** — the Inspector as an ordered list of sections: the generic
asset sections, the Settings section and its actions, and the merge with
the sections a type's `inspector.luau` declares (`inspector.assetSections`,
`inspector.settingsSection`), and the building blocks those sections
compose (`inspector.parts`, reached as `ctx.parts`).
- **`shell`** — the dock: one `ui.*` `dockArea` holding a `dockPanel` per
registered panel, and the panel registry behind it.
## Referencing
- Inside this package, modules reference siblings with `~.` — e.g.
`require("~.app")`, `require("~.widgets.fields")`.
- Editor content built on the framework references it by package identity —
`require("~edui.framework")`, `require("~edui.shell")`.
# Module (asset type)
A module is a reusable, stateless (or globally-stateful) Luau library
that other code pulls in with `require()`. Modules are the unit of
factored-out logic in a world: helpers, math libraries, format
parsers, registries, shared algorithms.
## When to use one
- You have logic you want to share across multiple components,
services, scenes, or tools.
- You have a registry, lookup table, or shared cache that callers all
read from / write to.
- You want a stable API surface (`M.fn`) other code can depend on.
If the logic is bound to one entity, use a `.component`. If you want a
named UI of fields rather than functions, use a `.preset`.
## Where it lives
- Source: `/zero/source/.../<name>.module/`
- Identity: the source path with `/` written as `.` and each segment's
type suffix dropped — `/zero/source/demo/beats.module` is
`demo.beats`, and `/zero/source/kit.package/beats.module` is
`kit.beats`, the container's name kept and its `.package` suffix
gone. `asset.create` returns this string, `asset.resolve(...).identity`
reads it back, and the `require` forms below write it as
`<identity>`.
- Folder shape:
- `init.luau` (or `init.lua`) — module body. **Required.** Returns
a table (conventionally named `M`).
- `README.md` — instance-level documentation. **Required.**
- `.metadata` — agent-editable tags + free-form fields. **Required.**
## How to create one
```luau
asset.create("module", "<name>")
-- Creates: /zero/source/<name>.module/
-- init.luau (canonical `local M = {} … return M`)
-- README.md (instance README template)
-- `folder` places it in a subfolder of /source, and that subfolder
-- leads the identity: `{ folder = "lib" }` produces `lib.<name>`.
-- `into` authors it inside a resolved container (a package, a toolbox),
-- whose own identity leads the same way:
asset.create("module", "<name>", { folder = "lib" })
asset.create("module", "<name>", { into = asset.resolve("myPkg.package") })
```
## How it operates
1. **Registration.** Writing `init.luau` into a `.module/` folder
indexes the asset and registers the module path with the resolver.
2. **Loading.** The first `require("<identity>")` runs
the file's body and caches the returned table. Subsequent requires
from anywhere return the **same table** — this is the
shared-state lever for "module-local" registries. The body runs in
an environment of the module's own: a name it declares without
`local` is readable by the module's own functions and by no other
script, so an export reaches its callers through the returned table
and nothing else. Requiring a component's folder runs its chunk the
same way, once, and its `update`, `start` and `public` stay in that
environment; a component runs on an entity through
`entity(id).component.add(name)`.
3. **Hot reload.** Editing the file re-runs the module body and folds
what it returns into the table already loaded, so that table keeps
its identity: a caller that captured it with `require` reads the new
source's functions and values through the reference it already
holds, and a later `require` returns that same table. A key the new
source drops goes away; a key something set at runtime stays. The
body's own `local`s start again from their initial values, so state
that must outlive an edit lives in `modules.state()`
(`guides { path: "core/scripting-and-tasks" }`).
4. **Identity resolution.** A module is reached by its `<identity>`,
and where the caller lives decides which spelling of it resolves.
For a module in a **world**, from a caller in that same world —
another module, a component, a scene entrypoint, or an `execute`
chunk:
- `require("<identity>")` — the identity on its own, resolved
against the caller's own root. It carries every folder segment,
so a module created with `{ folder = "demo" }` is
`require("demo.beats")`.
- `require("@root::<identity>")` — the same root-relative
resolution, written out.
- `require(".sibling")` — a module in the same folder, by its bare
name; `..name` steps up one folder, `...name` two.
Logs, stack traces and hot-reload notices name that same module
`@local.source.<identity>` — its key under the world source root.
The `<identity>` tail of that key is the form above, so a trace
reading `@local.source.demo.beats` is `require("demo.beats")`.
For a module in a **library** — content under
`/zero/source/libs/@<lib>/` — `@<lib>::` addresses that library's
root from anywhere: `require("@builtin::modules.transform")`.
Mounting a world as a library moves its files under such a root and
flips the caller root to `@<lib>::`, which is what keeps the
root-relative forms above resolving across the move.
## Discovery
- `asset.list("module")` — every registered module.
- `asset.inspect("<name>")` — public functions, source path, this
type README.
- `ls /zero/source/<name>.module` lists the files the folder holds.
## Authoring conventions
- Return a single `M` table from `init.luau`. Top-level statements
with side effects run on first require — useful for one-time
initialization, dangerous if they touch the engine before it's
ready.
- Write exported functions as `typed function`, not `function`: the
argument types are enforced at the call and the checker knows the
signature, so a caller's mistake is reported where they made it.
- Annotate exported functions with `--!desc` / `--!arg` / `--!return`
/ `--!example` so the LSP, `tools.list`, and `asset.inspect`
surface them. A function with no `--!desc` is reachable only by
someone already reading this file.
- Declare a VALUE with `Field.<kind>(default, mode, description)`, and
a table whose members are reached through a metatable with
`--!members <TypeName>` — the latter gives the surface its accepted
member set, its type, and its documentation from one table. See
`guides { path: "core/authoring" }` for all four rules and
`modules/api/engine/entity.module/members.module` for a worked
member table.
- Keep module state in module-local upvalues or in `modules.state()`.
A name the body declares without `local` lives in the module's
environment, which every run of the module shares: a function the
previous run left in place reads what the reload assigned. Module-locals start again from their
initial values with each hot reload; the table `modules.state()`
returns is the same table on both sides of every reload.
- Prefer focused modules over kitchen-sink modules. If two halves of a
module have no shared state, split them.
## Common pitfalls
- **Cyclic requires.** A `require` chain that loops will return the
partial table (the half built before the cycle was detected).
Design for one-way dependencies.
- **Engine-time side effects.** Don't `entity.spawn` at module
top-level — the engine may not be ready. Expose an `M.init` and
call it from a scene entrypoint.
- **Hot-reload + module-local cache.** A module that caches
expensive computation in upvalues loses that cache on reload —
fine for dev, but be aware in performance work.
- **`init.lua` vs `init.luau`.** Either works, `.luau` is canonical.
- **Writing one while play runs.** A `/source` write made while play is
running lands on the play shadow, and a guarded play-exit discards it
unless it is kept. One `.module` write shadows `init.luau`, the
`README.md` and the `.metadata` together.
`vfs.write(path, bytes, { durable = true })` skips the shadow, and
`vfs.promotePlayShadow` keeps what is already on it — the `core/vfs`
guide has the model and what each route costs.
## Related types
- `.component` — for entity-bound state + lifecycle hooks.
- `.service` — generates content you don't have yet (a mesh, sound, texture, …) via a metered provider.
- `.tool` — for a single agent-callable function with a YAML schema.
- `.package` — to group several modules + components + scenes into
one shippable folder.
## In the Inspector
Exports: what the module exports (name, kind, signature), parsed from its source without running it, with **Check** (the LSP's diagnostics for its entry file) and **Open**.
# edui.widgets (module)
Editor-chrome primitive builders for `edui`. Each returns a styled `ui.*`
widget subtree; the common ones are re-exported flat onto `edui`
(`edui.panel{...}`, `edui.text{...}`, `edui.iconButton{...}`, …).
Two things make these "framework" primitives rather than raw `ui.*`:
1. **They read the active theme's editor tokens** (`editor-row-height`,
`editor-selection-bg`, `editor-hover-bg`, `border`, `radius-md`, …) via
`ui.getToken`, so chrome looks like the editor by default and restyles with
the theme. `edui.palette()` returns the resolved set.
2. **Interactive builders register their closures with the currently-building
`edui` app** (`edui.current()`), so you pass `onClick = function() end` and
never touch a callback id.
## Builders
- Containers: `vbox`, `hbox`, `spacer`, `divider`, `panel`, `toolbar`.
- Content: `text`, `svgIcon`, `iconButton`, `button`.
- `panel{ title? | toolbar?, body }` is the standard dockable-panel shell (a
header over a height-filling body).
- `nodeGraph{ key, nodes, edges, selected?, height?, onSelect?, onMove?, onConnect?,
onDisconnect?, onDelete?, onOpen?, onField?, redraw? }` — a node graph on one
canvas: titled nodes with output and input ports, wires between them, and a value on
every input port that has no wire into it. Drag the background to pan, scroll to
zoom, drag a node to move it, drag from a port to another port to connect, drag a
connected input away to pick its wire up, click a value to edit it where it stands,
press Delete to remove the selection. The widget draws and reports; the owner holds
the graph and applies what `onField`, `onConnect`, `onDisconnect`, `onMove` and
`onDelete` report. Nodes with no position are laid out left to right over the wires.
`edui.nodeGraphView(key)` answers where the view stands and, through its `locate`,
where a port or a value is on the canvas.
- `iconButton{ d, tooltip?, active?, onClick, key }` — a hoverable/active icon
square; `d` is an SVG path (or full `<svg>`).
Icons are inline SVG (feather/lucide-style 24-view stroke paths), matching the
editor's icon language — pass a path `d` and it is wrapped for you.
# entityOps.addComponents
Attach component(s) — with their setup data — to one or many entities
in a single call, creating the entities first when asked.
```lua
entityOps.addComponents("crate", { Physics = { kind = "dynamic" } })
entityOps.addComponents({ "crate_1", "crate_2" }, { "Physics", "Audio" })
entityOps.addComponents("spinner", { Rotator = { speed = 2 } }, { create = true })
```
Targets are entity **names or ids** (arrays and `scene.find` results
pipe straight in). Components are a name, an array of names, or a
`{ Name = dataTable }` map carrying each component's setup data — names
accept the leaf (`"Physics"`), the full identity
(`"@builtin::components.Physics"`), or a VFS path, resolved before
anything mutates.
`create = true` spawns a fresh root entity for any string target that
matches nothing, so one call both creates the entity and gives it its
setup. Returns one `{ id, name, added, created? }` record per entity.
# entityOps.component
Inspect a component **type** so you set fields that exist instead of
guessing. Reports the component's public fields (name + type + current
value), its callable methods, its lifecycle hooks, and its asset-ref
fields.
```lua
entityOps.component("Camera") -- fields, methods, hooks + default values
entityOps.component("Model", { on = "my_prop" }) -- actual values on that entity
entityOps.component("@builtin::components.Light")
```
Resolves the component by name / identity / VFS path. Pass `on` (an
entity name or id that carries the component) and every field's `value`
is that entity's **actual** value, read off its live component proxy;
omit `on` and each `value` is the **declared default**, as written in the
component's source.
A live value keeps its shape: a number reads back as a number, a vector or
struct as its plain table. A field that resolves on read reports the identity
of what it points at — an asset (`resource` / `assetRef`) as a
`{ __ref, identity, name, type }` envelope whose `identity` you hand straight
back to `addComponents`, an `entityRef` as the entity id. A field whose live value could not be read
carries an `error` instead of a value, so a value that failed to read is
never mistaken for the default.
```lua
-- on a wall carrying a mesh and a custom material
entityOps.component("Model", { on = "wall_north" })
-- fields: model = { __ref = "336f4feb-…", identity = "@builtin::meshes.cube", name = "cube", type = "mesh" }
-- material = { __ref = "99d699e9-…", identity = "@user::materials.brick", name = "brick", type = "material" }
```
Returns `{ identity, description, builtin, executionOrder, hooks,
fields, methods, assetFields, source }`. Reach for it before
`entityOps.addComponents` / `entityOps.spawn` to learn the exact field
names and value shapes — the fix for setting fields a component doesn't
have.
To inspect the components + values on an *entity* (rather than a
component type's schema), use `debug.inspect`.
# entityOps.duplicate
Copy entities that already exist — one duplicate, or a numbered run of
them spread along an axis.
```lua
entityOps.duplicate("crate")
entityOps.duplicate("crate", { count = 5, offset = { 2, 0, 0 } })
entityOps.duplicate("pillar", { count = 4, offset = { 0, 3, 0 }, name = "pillar_%d" })
entityOps.duplicate({ name = { "tree" } }, { offset = { 10, 0, 0 } })
```
Targets take a name or id, a list of them, `scene.find` records, or a
**query** resolved for you — so everything matching `{ name = { "tree" } }`
is copied without looking the entities up first.
`count` makes that many copies of **each** source. It must be a whole
number of at least 1.
`offset` is a world-space `{x,y,z}` step that **accumulates**: copy 1 sits
one offset from the source, copy 2 sits two, copy 3 sits three. Every copy
is placed relative to the **source**, so a run spreads evenly instead of
compounding rounding from copy to copy.
`name` names each copy, and a `%d` in it becomes the copy's 1-based index
— `"pillar_%d"` yields `pillar_1`, `pillar_2`, … Without a `name`, copies
are named after their source (`crate_copy`, or `crate_copy_1`,
`crate_copy_2`, … for a run).
Copies carry the source's render layer.
An option key outside the documented set is an error that names it and
lists the accepted keys, so a mistyped `conut` is reported instead of
returning copies that quietly ignored it.
Every call returns the resulting
`{ id, name, position, localPosition, rotation, localRotation, eulerAngles, scale, parent }`
per copy, in creation order — the copy and the read are the same call.
# entityOps.fromAsset
Instantiate an existing asset into the scene — **resolution-first**: pass
a name / path / identity string, the tool resolves it and reports the
canonical asset it hit, so you never need to know the exact identity up
front.
```lua
entityOps.fromAsset("@builtin::avatars.humanoid")
entityOps.fromAsset("oak_chest", { type = "bundle", position = {2, 0, 0} })
entityOps.fromAsset("gold", { type = "material" })
entityOps.fromAsset("/zero/source/generated/meshes/a_statue.bundle", { link = false })
```
Dispatch by resolved category:
- **bundle / avatar** — instantiated via its own `:instantiate()`. `link`
(default true) keeps the live Asset-component link so the source drives
the hierarchy; `link = false` bakes the hierarchy into the scene.
- **mesh** — a renderable (Model + mesh Collider).
- **material** — a sphere carrying the material.
- **texture** — a plane sampling the texture (through a fresh unlit
material, so it never rewrites another preview).
- **anything else** — instantiated through its own `:instantiate()` when
it has one, else a legible error.
`type` limits the asset search to one category (avoids name clashes).
`position` / `rotation` / `scale` place it; `synced` replicates gameplay
edits to peers. Returns `{ id, name, resolved = { category, identity,
path } }` — `resolved` is the canonical asset your string hit.
To spawn from hand-named components instead of an existing asset, use
`entityOps.spawn`.
# entityOps.modify
Change entity state — one tool for delete / enable / disable / internal /
temporary / reparent / rename, over one or many entities resolved
by **name or id**.
```lua
entityOps.modify("debug_probe", { internal = true })
entityOps.modify({ "probe_a", "probe_b" }, { delete = true })
entityOps.modify("old_character", { enabled = "toggle" })
entityOps.modify("hat", { parent = "player_head" })
```
Ops: `delete` (removes the whole subtree; wins over everything else),
`enabled`, `internal` (engine plumbing: left out of the default entity
listings and the inspector's default view, and it keeps rendering),
`temporary` (booleans; `"toggle"` flips the current state), `parent` / `unparent` (with `keepWorldTransform`, default true),
and `rename` (single target only).
Returns one `{ id, name, applied }` record per target. `scene.find`
results pipe straight in as targets.
# entityOps.removeComponents
Detach component(s) from one or many entities — the counterpart to
`entityOps.addComponents`.
```lua
entityOps.removeComponents("lamp", "Light")
entityOps.removeComponents({ "crate_1", "crate_2" }, { "Physics", "Audio" })
entityOps.removeComponents({ component = { "Light" } }, "Light")
entityOps.removeComponents("lamp", "light") -- partial name, resolved
```
Targets take a name or id, a list of them, `scene.find` records, or a
**query** resolved for you — so a component is stripped from everything
carrying it without naming a single entity.
Component names match loosely: the leaf (`"Light"`), the full identity
(`"@builtin::components.Light"`), a VFS path, or a case-insensitive
partial. The response reports the **canonical** name it resolved to, so a
half-remembered name both works and teaches you the real one.
A name that could mean several components is an error listing the
candidates rather than a guess, and a name matching nothing is an error
too — nothing is silently skipped.
Every entity comes back as `{ id, name, removed, absent }`:
- `removed` — components it carried and lost.
- `absent` — components it never had, so nothing happened for them.
That split makes a call which changed nothing visible, instead of letting
it read like a success.
# entityOps.roots
Find the root ancestor of one or many entities — walks each up its
parent chain to the top-level entity.
```lua
entityOps.roots("player_hand")
entityOps.roots({ "wheel_fl", "wheel_fr" })
```
Targets are entity names or ids (a single one, an array, or `scene.find`
records). Returns one `{ target, targetName, root, rootName, depth }`
per target; an entity that is already a root reports itself with
`depth = 0`.
# entityOps shared
Cross-tool helpers for the `entityOps` toolbox — the pieces more than
one of its tools reuse.
- **Entity resolution** — `resolveEntity` / `resolveTargets` / `toList`
turn a name / id / proxy / `scene.find` record (single or a list) into
live entity proxies, raising a legible error on anything that doesn't
match.
- **Subtree removal** — `collectDescendants` / `despawnSubtree` remove an
entity and its whole subtree, raising rather than leaving a half-removed
tree behind.
- **Slot capture** — `captureSlot` snapshots the parent + local transform
+ name + sync flag an entity occupies, so a replacement can take its
exact place.
- **Asset resolution** — `resolveAsset` turns a caller's name / path /
identity string (or an already-resolved AssetRef) into a resolved
asset, reporting the canonical identity/path it hit, optionally limited
to one asset category.
Tools are thin wrappers over these; the helpers call the engine APIs.
# entityOps.spawn
Spawn entities from a template — you name the components they carry and
their field values, plus a transform.
## Many entities in ONE call
Pass a `{ defaults, items }` list: `defaults` holds what every entity
shares, each `items` entry overrides only what differs. A six-walled room
is one call, not six.
```lua
entityOps.spawn({
defaults = { components = { Model = { model = "cube" }, BoxCollider = {} },
scale = { 4, 3, 0.2 } },
items = {
{ name = "wall_n", position = { 0, 1.5, -2 } },
{ name = "wall_s", position = { 0, 1.5, 2 } },
{ name = "wall_e", position = { 2, 1.5, 0 }, rotation = { 0, 90, 0 } },
{ name = "wall_w", position = {-2, 1.5, 0 }, rotation = { 0, 90, 0 } },
},
})
```
- A per-item key wins over the matching `defaults` key.
- `components` merges **per component**: an item naming `Model` replaces
only that entry and keeps the shared `Collider`.
- Every item is validated **before any entity is created** — a typo in the
last entry fails the whole call rather than leaving a half-built scene.
- An unrecognised key is an error naming the accepted set, at the top
level, in `defaults`, and in an item alike.
- Returns one `{ id, name, components }` record per item, in item order.
## One entity
```lua
entityOps.spawn(
{ Model = { model = "cube" }, BoxCollider = {} },
{ position = {0, 1, 0} })
entityOps.spawn(
{ Light = { kind = "point", intensity = 5 } },
{ name = "lamp", position = {0, 3, 0} })
entityOps.spawn({}, { name = "group" }) -- bare entity, no components
```
Components is a `{ [ComponentName] = { field = value } }` map. Each is an
**authored** component (leaf name like `"Model"`, a full identity, or a
VFS path) added with its data so it **serializes** — native ECS
components are intentionally not exposed here, so you never author
something that renders at runtime but vanishes on save.
Transform: `position` `{x,y,z}`; `rotation` a `{x,y,z,w}` quaternion or
`{pitch,yaw,roll}` euler degrees; `scale` a number or `{x,y,z}`. Also
`temporary`, `internal`, `synced` (replicate gameplay edits to peers), and
`attributes`.
Returns `{ id, name, components }` with the component leaf names added.
To instantiate an existing **asset** (a bundle / avatar / mesh /
material / texture) rather than hand-name components, use
`entityOps.fromAsset`.
# entityOps.swap
Replace one entity with another entity that **already exists in the
scene**. The replacement is moved into the target's slot — same parent,
local position and rotation, the target's scale (`keepScale = false`
opts out) and name (`keepName = false` opts out) — and the target is
removed with its whole subtree.
```lua
entityOps.swap("DefaultBody", "my_knight")
entityOps.swap("placeholder_car", "sports_car", { keepName = false })
entityOps.swap("DefaultBody", "my_knight", { dryRun = true })
```
Both arguments are entity names or ids. `dryRun = true` reports what
would move and what would be removed without mutating.
To replace an entity with a content **asset** (a bundle/mesh/…) rather
than another scene entity, use `entityOps.fromAsset` (spawn) or
`appearance.replaceWithContent` (in-place slot swap).
# entityOps.transform
Move, rotate and scale entities that already exist — over one or many
entities.
```lua
entityOps.transform("lamp", { position = { 0, 3, 0 } })
entityOps.transform({ "wall_n", "wall_s" }, { offset = { 0, 2, 0 } })
entityOps.transform({ name = { "wall" } }, { offset = { 0, 2, 0 } })
entityOps.transform("crate", { rotation = { 0, 45, 0 }, scale = 2 })
entityOps.transform("lamp") -- no ops: a pure read
```
Targets take a name or id, a list of them, `scene.find` records, or a
**query** resolved for you — so you can move everything matching
`{ name = { "wall" } }` without looking the entities up first.
**Absolute** ops carry their space in the name: `position` / `rotation`
are world, `localPosition` / `localRotation` are parent-relative, `scale`
is a number or `{x,y,z}`.
**Relative** ops are `offset` (position delta), `rotate` (applied on top
of the current rotation) and `scaleBy` (multiplier). `space` —
`"world"` (default) or `"local"` — governs these.
`snap` quantizes the resulting position to grid steps.
Rotations take a `{x,y,z,w}` quaternion or `{pitch,yaw,roll}` euler
degrees, the same forms `entityOps.spawn` accepts.
Absolute and relative forms of one channel are exclusive — passing
`position` and `offset` together is an error rather than a silent
precedence rule.
An option key outside the documented set is an error that names it and
lists the accepted keys, so a mistyped `positon` is reported instead of
returning a successful-looking read of an entity that never moved.
Per-entity values in one call:
```lua
entityOps.transform({
{ target = "wall_n", position = { 0, 1, -5 }, rotation = { 0, 0, 0 } },
{ target = "wall_e", position = { 5, 1, 0 }, rotation = { 0, 90, 0 } },
})
```
Every record is validated and resolved before any of them is applied, so
a bad entry fails the whole call rather than moving its siblings and
leaving itself behind.
Every call returns the resulting
`{ id, name, position, localPosition, rotation, localRotation, eulerAngles, scale, parent }`
per entity — the mutation and the read are the same call.
# toolbox (asset type)
A toolbox is an asset grouping set of `<tool>.tool` assets around one area of work. Each tool in
it becomes callable under the toolbox `<toolbox>.<tool>`, and is a shell command,
`zero <toolbox> <tool> <args>`; `guides core/tools`, "A tool's command line", covers its
flags, paths, `render.luau` and exit status.
## When to group tools together
When creating tools for the engine, a common theme should be identified and
and a toolbox created to house them, this allows each individual operation
to be easily accessible instead of being scattered in a million places.
## Sharing functionality between tools
A toolbox features ability to define functions that code inside each individual tool
inside it can access, this is usefull when establishing helpers etc so you dont have
to duplicate code for each new tool you write.
A `shared.module` inside the toolbox root is where this code lives,
each tool inside a toolbox can access its functions by requiring it with `require(".shared")`.
```luau
-- <toolbox>.toolbox/shared.module/init.luau
local M = {}
-- One step a tool reports in its result.
export type Step = { name: string, ok: boolean, detail: string? }
--!desc Check that a numeric argument lies within bounds.
--!arg arg The argument's name, for the error.
--!arg value The value passed.
--!arg min The lowest value allowed.
--!arg max The highest value allowed.
--!return The value; raises naming the argument and the range when it lies outside.
--!example "count", 12, 1, 100
typed function M.range(arg: string, value: number, min: number, max: number): number
if value < min or value > max then
error(string.format("%s must be between %s and %s, got %s", arg, tostring(min), tostring(max), tostring(value)))
end
return value
end
--!desc A byte count as a readable size.
--!arg bytes The count.
--!return The size in B, KB, MB or GB.
--!example 2681107
typed function M.size(bytes: number): string
local units = { "B", "KB", "MB", "GB" }
local i = 1
while bytes >= 1024 and i < #units do
bytes /= 1024
i += 1
end
return if i == 1 then string.format("%d %s", bytes, units[i]) else string.format("%.1f %s", bytes, units[i])
end
--!desc A step for a tool's result.
--!arg name What the step did.
--!arg ok Whether it succeeded.
--!arg detail What happened, when there is more to say.
--!return The step.
--!example "copy textures", true
typed function M.step(name: string, ok: boolean, detail: string?): Step
return { name = name, ok = ok, detail = detail }
end
--!desc The asset of `kind` that a caller named, looked up by that name.
--!arg kind The asset type to look in.
--!arg name The name the caller passed.
--!return The asset; raises naming the kind and name when nothing matches.
--!example "material", "gold"
typed function M.named(kind: string, name: string): AssetRef
local ref = asset.tryResolve(name, kind)
if ref == nil then
error(string.format("no %s named '%s'", kind, name))
end
return ref
end
return M
```
This shared code should be limited to being used by the tools inside it,
dont put general functionality you might need otuside the toolbox into its shared module.
Instead reference those in the shared module should you wish to utilize something.
A benefit the shared module shares with the tools own code is that it allows
the author to write code that has computed references, meaning eg resolving
an asset from a computed variable `asset.resolve(<type>,name)` that is normally
not allowed in other parts of the engine surface, due to said references not being
recorded.
This is usefully for utilizing tools to handle operations that are called by users/agents
and are dynamic in nature, such as finding/inspecting/testing assets, or content based on an input etc.
When writing a shared module, you should follow standard module practices, please see `module.assetType` readme.md
for more indepth information.
## Describing the toolbox
When writing the readme for your toolbox, ensure you focus on the overall
area what the toolbox focuses on, rather than listing individual tools inside it,
discovery surfcaces already group tools and toolboxes together so a toolbox can be discoverd
by the tools it hosts and doesnt require separately maintaining a list of the tools in it's readme.
## What are tools and when do i create ones?
Tools are typed operations with a known serialized output format, made to enable efficient operation in the engine and provide an easily callable interface for operations around a topic.
They are also useful in that they can be called from a multitude of surfaces, from `execute`, to `bash` to `tool_exec`
to users Tools portion in the edui.
A toolbox and its tools differ from eg a module that has multiple callable functionm in that they might return anything,
and come with no guarantee that the output is meant to be inspected directly, where as tools are meant to perform an self contained operation and return results/info/relevant data in a readable format, including eg. image data.
Whenever you identify an operation that requires specific orchestration and or is something that could be a repeated operation and makes it easier to manage the project/task or when you want to expose logic written in `luau`
to the other call surfaces like `bash` under its `zero` command,you should reach for creating a toolbox.
Toolboxes also come in handy for limiting control/inputs, exposing a limited set of functionality in a clean manner or ensuring the caller doesnt have to understand the entire code.
For comparison, you could think of toolboxes as programs, and the tools inside them as commands.
A package might contain tens of tousands of lines of code, dozens of modules, components etc,
a toolbox turns that surface into a system that any agent/user can then utilize without having
to read or understand the code inside.
Its the UI equilevant to operations.
For the indepth explanation of what `tool.assetType` is and does, read it's readme.
# edui.shell (module)
The editor dock shell on the CSS-parity `ui.*` surface. One edui app owns a
`ui.*` native `dockArea` whose children are a `dockPanel` per registered edui
panel — real `egui_dock` tabs, splits and drag, with the arrangement persisting
across rebuilds because the dockArea and each dockPanel carry a stable `id`.
## Why a separate registry
The shell keeps its own panel registry (`addPanel` / `removePanel` /
`panelsSorted`), distinct from the deprecated zui `editor.registry`. That keeps
the zui editor completely untouched while panels migrate to edui one at a time:
the zui dock renders the zui-framework panels it always has, and the edui shell
renders the edui panels registered here. The two registries fold into one at
cutover, when the zui dock is retired.
## One app, one reactive loop
`App.rebuild` sets the shell as the building app before it calls `buildShell`,
so a panel's `build()` — which uses `edui.current()` to register its closures —
wires every callback onto the ONE shell app. All interaction for every panel
flows through the shell's single callback env, and a click anywhere rebuilds the
whole dockArea. That is why the shell needs no per-tab scheduler (unlike zui's
`dockApp`): the edui App is the scheduler.
## Usage
```lua
local edui = require("@builtin::modules.edui")
edui.shell.addPanel{
id = "entities", title = "Entities", order = 10,
build = function()
return edui.panel{ title = "Entities", body = edui.tree{ ... } }
end,
}
edui.shell.mount() -- registers the screen on the EditorUI layer
-- each editor-update frame:
edui.shell.update(dt) -- liveness rebuild every `refresh` seconds
```
`mount(opts?)` takes `{ refresh? }` (seconds between liveness rebuilds, default
0.5). `refresh()` forces an immediate rebuild; `unmount()` tears the screen down
but keeps the panel registrations for a later `mount`.
# capture
The newest frame a capture produced on this engine, drawn full-pane, with the
shot's number, where it was rendered from, which pass it holds and its pixel
size on the toolbar.
The frames come from `@builtin::tools.capture.feed`, which every capture
publishes to. A frame still on the GPU is drawn from its own render target, so
the picture is the one the engine already holds; a capture given a `path` is
drawn from the file it wrote there. The `watch` layout puts this tab under the scene, so
the person at the window sees the same frame the agent got.
# assetType runtime
The machinery that reads a `<typename>.assetType/behavior.luau` and turns its
declarations into live behaviour.
A `behavior.luau` is a table of declarations — `ref` methods, `modules` shared
code, an `events` schema, a `namePattern`, `refShapes`, and the `onCreate` /
`onRegister` / `onChange` / `onDelete` / `validate` / `settingsDefaults` /
`settingsCorrections` hooks. None of it runs itself. This is the code that
runs it, and it lives here because reading a type's declarations is the
**assetType type's own behaviour** — the same way `material.assetType` owns
what a `.material` does.
## Sub-modules
| Module | Reads | Responsibility |
|---|---|---|
| `ref.module` | `ref`, `modules` | Builds every `AssetRef` envelope, attaches the shared metatable, and dispatches per-type methods and shared modules onto it. Also owns edit-mode write-behind persistence. |
| `create.module` | `onCreate`, `namePattern`, `validate` | Backs `asset.create`: resolves the type, checks the name against its pattern, runs `onCreate` (or clones `template/`), and writes the instance. `validate.module` beside it checks a creation `opts` table against the type's `createSchema`. Before running `onCreate`, resolves the type's settings chain (below) and hands the result to the hook as `opts.settings`. |
| `settings.module` | `settings`, `settingsDefaults`, `settingsCorrections` | A type's declared settings schema and where its values live (`type.yaml`'s `settings:` block). `Settings.resolveForCreate` layers the schema's own defaults, the type's own `settingsDefaults(name, opts, asked)` hook (a DEFAULT the schema can't express — a name-derived convention, a fact read off a payload the caller handed it, a value following a field `asked` shows a higher layer naming; any later layer overrides it), the Preset Manager, an importer's settings, the caller's `settings` table, then the type's own `settingsCorrections(values, name, opts)` hook (a CROSS-FIELD CONSTRAINT the schema can't express, applied last over the fully merged values). A correction over a default/preset/importer value lands silently; a correction that would override what the caller's own `settings` table explicitly asked for refuses the creation instead, naming the field and why. Neither hook is ever handed a table to mutate; each returns what it wants changed (`settingsCorrections` may also return a `{ [field]: reason }` table for that refusal message). `Settings.cloneValues` deep-copies a values table — `create.module` hands `onCreate` a copy, never the table it stamps. `Settings.valuesOf` / `writeValues` read and write an asset's own values file. |
| `typeYaml.module` | `type.yaml` | The folder a type lives in and its parsed `type.yaml`, decoded once per content version of the file. `settings.module` and `inspector.module` read their blocks through it. `about` / `aboutAt` read a type's `about.yaml` (`intent`, `function`, `usage`), leaving out any key that is empty or still starts with `[[describe]]`; `aboutRows` and `aboutMarkdown` lay the texts out for the Inspector and the `types/<name>` guide. |
| `inspector.module` | `type.yaml`'s `inspector:` block | Which inspector a type declares for its assets (`inspector: { type: ... }` or `{ instance: ... }`), and the declaration that file returns — the sections it adds, the generic ones it replaces, and their order — or the problem that kept it from loading. |
| `onRegister.module` | `onRegister` | Fires an instance's once-only registration hook — on arrival, on world load, and for `@builtin` library instances. |
| `changeDispatch.module` | `onChange`, `onDelete`, `refShapes` | Routes a VFS source write or a folder delete to the enclosing typed asset's type hooks. |
| `refShapes.module` | `refShapes`, `ref` | Publishes what every `AssetRef<category>` answers to, so a member read on an asset-typed value is checked against that category's real surface. |
| `events.module` | `events` | The per-asset event runtime behind `ref.events`. |
| `instantiable.module` | `ref.instantiate` | The instantiation contract an asset type opts into: `root` stands the root entity, `place` applies the base placement opts to one the type adopted, and `result` shapes the `(root, idMap)` every `instantiate` returns. Also registers the `sceneInstantiable` field-constraint validator. |
| `declaration.module` | `type.yaml` | The type's decoded declaration, read once and held until a write inside an `.assetType` folder; what every question about a type as a whole reads. |
| `previewRecipe.module` | `type.yaml` `preview:` | How an instance's `preview.png` is produced: which of the four recipes (`instantiate`, `image`, `surface`, `custom`) the type declares, and what that recipe needs. |
## Reaching it
```luau
local rt = require("@builtin::assetTypes.assetType.shared")
rt.ref.loadTypeBehavior("material")
```
Fields resolve lazily. The prelude requires the sub-modules directly, in
dependency order (`ref`, then `changeDispatch`, `onRegister.install()`,
`refShapes.install()`) — a table that required all six on load would take that
ordering away from it.
# Package (asset type)
A package is an asset — a `<Name>.package/` folder that bundles
components, modules, scenes, presets, tools, and any other typed
sub-assets under one identity, installed into a world as one unit.
Packages are how authoring sets get distributed across worlds.
A **library** is the addressable root scope content resolves under
(`@builtin`, `@<name>`) — a whole world mounted into this one under a
namespace, via `zeromind.installLib` / `world.installLibrary`. A package is
an asset that lives inside such a root, and one library holds as many
packages as its author put there. A package is installed by guid the
way every asset is (`zeromind.installAsset`).
## When to use one
- You're authoring a coherent feature suite (character controller
stack, voxel engine, UI kit, animation library) and want to ship
it as one install target.
- You want a stable identity worlds can install and resolve sub-assets
against (`@<lib>::pkg.sub_module`).
- You want versioning + a per-package metadata layer that travels with
the contents.
If you're authoring inside a single world and don't need a separate
install lifecycle, you don't need a package — drop your `.component`
/ `.module` / etc. directly in `/zero/source/`. Packages are for
cross-world distribution.
## Where it lives
- Source: `/zero/source/.../<Name>.package/` (or, for legacy
packages, a folder containing `package.yaml` at its root).
- Identity: `<Name>` (the `.package` suffix collapses in identity —
mirrors `.module`). A file at `<Name>.package/<sub>/init.luau`
resolves under the same identity it would at `<Name>/<sub>/init.luau`.
- Folder shape (container-style — open child set):
- `package.yaml`: metadata (name, version, description) and the
packages it depends on (`dependencies`). **Required.**
- `README.md` — instance documentation. **Required.**
- `.metadata` — agent-editable tags + free-form fields. **Required.**
- Sub-asset folders: any combination of `.component/`,
`.module/`, `.scene/`, `.preset/`, `.tool/`, `.toolbox/`,
`.material/`, `.shader/`, etc.
The validator permits unlisted children (`allow_unlisted: true`) by
design — packages are open containers.
## How to create one
```luau
asset.create("package", "<Name>")
-- Creates: /zero/source/<Name>.package/
-- package.yaml (metadata scaffold)
-- README.md (instance README template)
-- `folder` places it in a subfolder of /source instead of the root:
asset.create("package", "<Name>", { folder = "systems" })
```
Then scaffold sub-assets inside it:
```luau
local pkg = asset.resolve("<Name>.package")
asset.create("component", "Spinner", { into = pkg })
asset.create("module", "util", { into = pkg })
```
## `package.yaml`
```yaml
name: inkBlocks # optional; the folder stem when absent
version: "1.0.3"
description: "Ink and paper style blocks"
dependencies:
- { name: starterBlocks, version: "1.0.8" }
- styleKit # a bare name states no version
```
`dependencies` lists the packages this package needs. Each entry's `name` is
a reference the package records, the same kind of reference a `require` or an
asset name in a data file makes:
- **It resolves in the author's world.** Install the dependency here first
(`zeromind.installAsset`); the entry then names the copy this world holds.
A push refuses a package whose dependency resolves to nothing, naming it.
- **An install brings it along.** Installing the package installs every
dependency it lists, at the version this world holds when the package is
pushed, under `/source/deps/<owner world>/`, deduplicated against what the
installing world already holds. `zeromind.preview` lists each one before
anything is written, and the install's `deps` lists what it brought.
Uninstalling the package leaves a dependency that another installed
package still uses.
- **`version` is checked, not chosen.** A stated `version` has to equal the
`version` the dependency's own `package.yaml` states in this world;
`asset.validate` (and so the push) refuses the package naming both when
they differ. To depend on another version, install that version here.
## How it operates
1. **Registration.** Writing `package.yaml` indexes the package with
the package registry.
2. **Install.** A package is read before it is installed: `zm ls-tree
@<guid>` in the shell lists what it contains, and `zm show
@<guid>:<path>` and `zm grep <pattern> @<guid>` read it, so candidates
are compared by what they do. The one that fits is installed by guid,
the way every asset is: `zeromind_install` over the engine's MCP, or
`tools.use("zeromind", "installAsset", <guid>)` inside the engine. The
install writes the package's files (and the deps its `.refs`
record, the packages its `package.yaml` lists under `dependencies`
included) into this world's source, so its sub-assets resolve here.
`tools.use("zeromind", "preview", <guid>)` reports what an install would
write before it writes anything.
3. **Sub-asset resolution.** Because `.package` collapses in
identity, sub-asset paths work whether the package folder is
suffixed (`<Name>.package/<sub>`) or not (`<Name>/<sub>`).
4. **Updates.** `tools.use("zeromind", "updates")` lists installed content
with upstream changes available; re-running the install pulls them.
5. **Metadata.** `package.yaml::name` overrides the folder stem if
present (rare); `version` + `description` are surfaced in the
package index.
6. **Hot reload.** Edits to sub-assets hot-reload as normal; edits to
`package.yaml` reload package metadata.
## Discovery
- `asset.list("package")` — every registered package.
- `asset.inspect("<name>")` — sub-asset catalog, source, this type
README.
- `ls /zero/source/<Name>.package` lists the files the folder holds.
- `library.list()` — the library assets registered in this world,
including the ones packages under an installed library contribute.
## Authoring conventions
- Name packages by their feature (`voxels`, `cameraRigs`,
`dialogSystem`), not by their owner — the host library is the
`@<lib>::` scope prefix.
- Cluster cohesive sub-assets together. A "character controller"
package should ship the controller component, its preset configs,
its supporting modules, and a demo scene — not just the component.
- Document the package's surface in `README.md` — what install
installs, what each sub-asset does, how they relate. Agents reading
`cat /zero/source/<Name>.package/README.md` get the full picture in one shot.
- Version conservatively — breaking a package means breaking every
world that installed it. Use semantic version bumps.
## Common pitfalls
- **Missing `package.yaml`.** Without it the folder isn't recognized
as a package even if it has a `.package/` suffix.
- **A dependency named only by a string the code builds.** A package
whose files reach another package only through a name assembled at
runtime records no reference to it, so an install arrives without it.
List that package under `dependencies` in `package.yaml`.
- **Identity collapse.** Sub-asset paths skip the `.package` suffix.
Don't include `.package` in `require` strings.
## Referencing inside a package: the `~` rule
`~` means **this package**, resolved structurally from the referring file's own
location. It is the only package-specific syntax. It is rename-safe (no package
name is ever written) and library-agnostic (it never names the host library, so
it survives `@builtin` being renamed or the package being mounted elsewhere).
`~.tail` maps to `<pkg>.package/tail` from anywhere inside the package.
| Referencing from | Use | Example |
|---|---|---|
| An asset/module **inside this package** | `~.tail` | `require("~.modules.myThing")`, `shader: "~.shaders.myThingBlend"` |
| A **different package** under the same root | root-relative identity | `require("@root::systems.otherPkg.modules.x")` |
| A **different library's** public API (a deliberate external dependency) | `@otherlib::…` | `require("@physics::modules.rigidbody")` |
**Never write `@builtin::` (or any host-library name) to reference your own
package** — that couples the package to the library it currently lives in and
breaks if the library is renamed or the files move. Use `~.`. It works from
Luau `require()` and from asset-reference strings in data files (a material's
`mat.yaml` `shader:` field, a component's default asset ref); the engine
resolves it against the referring file's own package. `asset.resolve` takes a
`~.` name the same way, against the package of the file that calls it:
`asset.resolve("~.materials.myThingStandard", "material")`.
`~.` is the package-relative self-reference; `@root::` is the root-relative one
(the library root, or the world source tree for non-library content). The
`core/requiring-modules` guide covers the root model in full.
A package that ships substantial functionality should include a `.guide` asset
(a `<name>.guide/guide.md` folder anywhere under the package); the `guides` tool
discovers it live, so collaborators find the system the way they find built-in
guides. A package's test suite reaches the shared `Test` framework through its
enclosing asset: `local Test = asset.containing(__FILE__).modules.shared`
(`asset.containing` returns the deepest enclosing typed asset, the `.testSuite`,
not the outer `.package`).
## Related types
- Any of `.component`, `.module`, `.scene`, `.preset`, `.tool`,
`.toolbox`, `.material`, `.shader`, `.style`, `.service`,
`.importer` — packages bundle these.
## In the Inspector
Package: the name, version and description package.yaml declares, how many things the package holds and what they are, and **Open** for package.yaml. A package.yaml that does not decode is listed under Problems with the decoder's error.