# editor_observe What an editor action committed, and why it committed less than it was asked for. Every editor action — a gizmo drag, a delete, a duplicate, a command dispatch, a selection gesture — closes by publishing one record here, and returns that same record to its caller. Nothing is measured per frame: a record is written where the work happens and read lazily. ```lua local Obs = require("@builtin::modules.api.editor.editor_observe") Obs.observe() -- the whole document: last of each kind, history, counts Obs.last() -- the most recent action of any kind Obs.last("drag") -- the most recent drag Obs.history() -- every retained action, oldest first ``` The same reading is a tool: `tools.use("editor", "observe")`. ## What every record carries - `action` — `drag`, `grab`, `delete`, `duplicate`, `command` or `select`. - `outcome` — `committed`, `partial`, `refused`, `cancelled` or `noop`. - `reason` — the nearest cause, from the closed set below, when the outcome is anything but a clean commit. - `detail` — the engine's own words for that cause. - `entities` — one row per entity the action touched or tried to, each with `before`, `requested` and `after`, and its own `reason` when it is not a clean commit. - `committed` / `changed` / `refused` — how many rows fall in each. - `seq`, `atMs`, `durationMs` — which action this is and how long it was open. ## The reason set `selectionEmpty`, `entityMissing`, `writeRefused`, `writeDiverged`, `pivotLost`, `userCancelled`, `commitFailed`, `duplicateRefused`, `despawnRefused`, `unchanged`, `commandMissing`, `commandDisabled`, `predicateRaised`, `bodyRaised`, `hitNothing`, `pointerBlocked`. `Obs.REASONS` maps each to its one-line meaning, so a caller can enumerate the set rather than guess at it. ## A drag that moved less than asked The drag record separates the three quantities that are usually conflated: - `pointerAsked` — what the pointer's position asked for, before snapping. - `applied` — what the gizmo handed the engine, after snapping. `snapping` and `snapIncrement` say why the two differ. - each entity's `after` — the transform the engine **holds**, read back from the engine rather than recomputed from the drag's own arithmetic. An entity whose `after` differs from its `requested` reads `writeDiverged`; one whose write raised reads `writeRefused` with the message; one despawned mid-drag reads `entityMissing`. A drag that ended on Esc reads `cancelled` / `userCancelled`, and one whose selection emptied under it reads `cancelled` / `pivotLost` — three terminal states a single "the object did not move" cannot tell apart. ## A drag that never began A press that lands on a handle and starts no drag publishes a `grab` record instead — `Obs.last("grab")`, or `Gizmo.lastGrab()`. `pointerBlocked` says the UI layer held pointer focus, so the press never reached the handle. A press away from every handle is a selection click rather than a grab, and records nothing. One record per press: a frame that ticks the gizmo more than once reports the press once. `unit` names what `pointerAsked` and `applied` are measured in: `metres` for a translate or plane drag (a world-space `{x,y,z}` delta), `radians` for a rotate (`{radians}`), `factor` for a scale (`{factor}`). ## Per-frame cost The editor's own per-frame work is named in the profiler rather than pooled into `lua_update`: `script.editor.gizmo.tick`, `script.editor.viewport.select`, `script.editor.selection.highlight`, and `script.editor.panel.<id>` for each dock panel's rebuild. Read them with `profiler.stats()`.

# 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.