---
title: UIX — the thesis
type: reference
audience: human + agent
authority: E1 architecture — the narrative introduction to the four layers and their boundaries
status: current
source: migrated from src/uix/README.md (2026-07-02, docs-book F7.2)
---

# UIX

A short architectural positioning document for `src/uix`.

> **Whole-system view**: to understand the four layers (morfo, soma, sema,
> eidos) in a single read — motivations and articulation included — go to
> [`active-architecture`](./active-architecture.md). This document
> keeps the more narrative introduction.
>
> **Semantic vocabulary** (families, intents, verbs, channels): the single
> source of truth is [`CANON.md`](../CANON.md), anchored to the book and the
> code. (The original Spanish implementation guide survives as a historical
> seed at [`decisions/guia-semantica-historica.md`](../decisions/guia-semantica-historica.md).)

UIX does not try to be "another component library". The bet is more ambitious
and structural: **separate layers that almost every current framework keeps
mixed together**.

In most UI systems these things live glued to each other:

- the component's public DOM contract
- headless behavior
- accessibility
- event semantics
- the visual layer
- modal engines (sound, haptic, motion)
- app-service integration

UIX splits that block into pieces with strong boundaries.

---

## 1. The central idea

UIX models the interface as several cooperating layers, not as one giant
component that does everything at once.

```text
App
├─ cross-cutting services (active-app)
│  └─ adom, langs, format, ...
└─ components
   └─ structural / semantic / behavioral / visual layer
```

The intuition:

- a component's public structure is not the same as its behavior
- an event's semantics are not the same as its materialization
- the active DOM is not the same as pure DOM utilities
- the app should not couple modal engines to each other

UIX gives those separations explicit names and contracts.

---

## 2. The UIX layers

### `Morfo` (`src/uix/morfo/`)

The component's cross-layer structural contract. It declares `parts`,
`data-*`, ARIA, focus, keyboard, events and — when text belongs to the
contract — the component's `texts` slots (idlangrefs). It is neither prose nor
runtime: it is the canonical public shape.

See: [`architecture/morfo.md`](./morfo.md)

### `Sema` / Events (`src/uix/sema/`)

The semantic vocabulary and the orchestration of perceptual events. `sema`
remains the historical folder name; `ActiveUix`'s public surface calls the
service `events`.

- canonical families (8): `contact`, `commit`, `signal`, `handle`, `emerge`,
  `shift`, `sustain`, `delegate`
- canonical intents: `neutral`, `affirm`, `fulfill`, `risk`, `threat`, `loss`
- `uix.events.emit(signal)` for providers to publish occurrences
- a channel registry (`VisualChannel`, `SoundChannel`, `HapticChannel`)
- `src/uix/sema/channels.ts` as the single source of channel ids, signatures
  and overrides
- `src/uix/sema/sounds.ts` as the single nominal repository of synthetic
  sounds, external `.wav`s and dynamic recipes
- the `VisualChannel`'s window: it prepares `data-event-*` through a DOM
  projector, holds them for the `hold` window, waits for the expression and
  cleans up BEFORE resolving `EmitHandle.settled` — a window that gates nobody,
  since `emit` returns its handle synchronously (D-full, 2026-09-15)

Sema does not decide what happened (the provider decides that). It only
orchestrates the occurrence and dispatches it to the registered channels.

See: [`architecture/sema.md`](./sema.md)

### `Soma` (`src/uix/soma/`)

The headless behavior layer: state, context, a11y, keyboard / pointer /
focus, event emission.

Soma does not know the concrete implementation of the modal engines. Its job
is to emit the component's facts, not to materialize them.

See: [`architecture/soma.md`](./soma.md),
[`SOMA_ARCHITECTURE.md`](./soma-architecture.md)

### `Eidos` (`src/uix/eidos/`)

The visual layer: tokens, themes, per-component CSS recipes, archetype rules,
event reactions and **Svelte wrappers** over soma's headless providers with
the visual props (variant, size, block, iconOnly, icon, checkMark).

The general module is flattened into `ActiveEidos`:

- `ActiveEidos` — the active runtime / visual context created by
  `ActiveEidos.create(...)`. It manages visual configuration, primitives,
  canonical roles, themes, validation, CSS generation and persistence. With
  `ActiveUix` services it receives `dom`, `langs`, `prefs` and `format`;
  `mode` and `density` arrive through explicit sources or its own defaults.
  It injects `<style data-uix-eidos>` only when the app wants runtime CSS
  instead of precompiled CSS.

The app can provide a full `EidosConfig` or a partial `themeBase` patch via
`ActiveEidos.create({ config/themeBase })`, or delegate theme values to
external CSS with `themeSource: 'css'`. `getCssContract()` exposes the typed
list of custom properties and `renderContractCss()` publishes it as empty CSS
for external themes. For editors or live preferences, `ActiveEidos` can
inject a runtime variable map into its own `<style>` validated against that
contract. When the app wants to persist a full configuration, it stores a
versioned `EidosConfigDocument` (`kind + version + options`) and can pass it
back as `ActiveEidos.create({ config: document })`.

Eidos's `size` is canonical and discrete: `xxs..xxl/full`. ActiveEidos
generates coordinated physical tokens for `xxs..xxl`; `full` stays reserved
for responsive layout.

The generated contract also includes alpha color scales
(`--scale-blue-a1..a12` and `--primitive-primary-a1..a12`), border
(`width/style` + aliases), layout (`containerWidth`, `contentWidth`,
`aspectRatio`), density scalars wired to `data-density`, opacity, z-index and
shadows with a physical `1..6` scale plus per-theme semantic aliases. The
active recipe aliases (`--toast-*`, `--dialog-*`, etc.) live in
`EidosConfig.recipes`; the generated static artifact lives in
`src/uix/eidos/generated/base.css` and `src/uix/eidos/index.css` imports it
as the foundation for SSR/docs with `ActiveEidos.create({ applyDom: false })`.
The old `contracts/` and `themes/base/` CSS were retired from the active
tree; the contract is obtained from `ActiveEidos.getCssContract()` /
`renderContractCss()`. The `tokens/` directory is no longer part of the
runtime. `ActiveEidos.listRecipes()` and `getRecipeTokens(component)` expose
those aliases for theme editors without reading CSS.

Every soma component ships an eidos wrapper (the Soma → Eidos migration
completed in 2026-05): each wraps soma's public parts and adds only visual
surface. The live inventory is the `eidos/components/` tree plus
`npm run component:audit`.

Eidos reads from the DOM what the other layers write (parts, data-attrs,
ARIA, event signals) — it never imports soma or sema internals.

See: [`architecture/eidos.md`](./eidos.md)

### `active-uix` (`src/uix/active-uix/`)

The composition root. Only `ActiveApp` and `ActiveUix` may create shared
services:

- `createActiveUix(options)` — standalone; instantiates services and `prefs`
  internally.
- `attachActiveUix(activeApp)` — attaches to an `ActiveApp` already composed
  by the application; validates the required services and creates no
  substitutes.

Active layers consume `ActiveUix` via `getActiveUix()` and expose the minimal
surface their components need. Soma components read `Soma`; eidos components
read `ActiveEidos`. That way they neither know which boot path was used nor
depend on the full `ActiveUix` surface.

Full chapter: [`architecture/active-uix.md`](./active-uix.md)

#### ActiveUix and prefs

`ActiveUix` neither requires nor knows `arts/frontend`; that artifact was
retired. The pattern follows `ActiveApp`: `prefs` is core and consumer layers
sync from its dimensions, but each layer projects only what it owns.

- `prefs.language` syncs the active language of `uix.langs`.
- `prefs.locale` feeds `uix.format`.
- `prefs.direction` is the single source of effective direction; it derives
  from `language` when there is no override.
- `prefs.motion`, `prefs.sound` and `prefs.haptic` are cross-modal
  perception/interaction preferences.
- `theme`, `mode` and `density` belong to Eidos: `theme` names the visual
  family, `mode` resolves `light | dark`, and `density` tunes visual
  ergonomics.

Global writes go through whichever `ActiveDom` is injected, never direct
mutations:

```text
ActivePrefsDomProjection -> dir, data-motion, data-sound, data-haptic
ActiveEidos              -> data-theme, data-mode, data-density
```

`ActiveUix` does not auto-create `ActivePrefsDomProjection`. That projector
belongs to `arts/prefs` and the composition root wires it when it wants those
global attrs. Eidos is created separately through `ActiveEidos` when runtime
visuals are needed.

Example of a standalone UIX shell (like the docs' `/uix` route):

```ts
const uix = createActiveUix({ langs, prefs: { schema } });

setActiveUix(uix);
Soma.create();

const prefsProjection = createActivePrefsDomProjection({ prefs: uix.prefs, dom: uix.dom });
const eidos = ActiveEidos.create({ applyDom: true });
```

The light/dark toggle feeds `uix.prefs.setIntent('mode', …)`; eidos reads the
slot and re-applies `data-mode` + `data-theme` (2026-09-14: `mode`, `theme`,
`density` and `scaling` are prefs dimensions).

In standalone mode, `createActiveUix()` instantiates `ActivePrefs` with the
standard UIX preset and creates the configured services. In attach mode,
`attachActiveUix(app)` reuses `app.prefs`, `app.langs`, `app.dom`,
`app.clipboard`, `app.format` and the perceptual engine when they exist. UIX
exposes it as `uix.events`; in attach mode `ActiveApp`'s service is called
`events`. `langs` and `dom` are required for attach; if missing, an early
error is thrown. `clipboard`, `format` and `events` are optional services:
if a layer asks for them and `ActiveUix` does not expose them, they fail with
an explicit error instead of creating substitutes.

`soma.prefs` is the preferences view the headless providers need, backed by
`uix.prefs`, not by `frontend`.

### `adom` (`src/arts/adom/`, alias `$adom`)

The application's active DOM runtime. It is not a semantic engine. Its only
job is to **coordinate and synchronize DOM mutations** via
`app.dom.apply(change)` and `app.dom.remove(target, names)`.

ADom receives already-resolved instructions. It does not interpret them.

See: [`src/arts/adom/README.md`](../../src/arts/adom/README.md)

### `libs/dom` (`src/libs/dom/`)

Pure or nearly-pure DOM utilities (`contains`, `getDocument`, `getWindow`,
focus, traversal, base observer wrappers). It contains no active runtime —
that role belongs to `adom`.

---

## 2.bis How a component executes

The closed architecture (post-2026-04-25) defines six pieces with disjoint
responsibilities. None invades the next.

```
Morfo            declares
SomaRuntime      transcribes
Provider         supplies sources, targets and handlers
Render bag       re-derives attrs from state (Svelte renders them)
EngineSemantic   orchestrates prepare + dispatch to perceptual channels
VisualChannel    prepares data-event* via SignalProjector + holds
SignalProjector  projects data-event* via uix.dom
ADom             applies DOM mutations (the structural commit)
```

### The operational split

`Morfo` is DNA: one file per component declaring `parts`, `data-*`, `aria-*`,
`role`, `keyboard`, `focus`, `events`. It executes nothing.

`SomaRuntime` (in `soma/`) interprets the morfo. One instance per component
receives from the provider the state sources, the DOM targets and the event
handlers. It exposes `partProps(part)`, `attachPart(part, target)`,
`keydown(part, event)`, `trigger(eventName)`.

`Provider` supplies what the morfo cannot infer: reactive getters for
`states` and `props`, reactive getters for `parts` (dynamic ids), synchronous
handlers for the `events`, and the glue for orthogonal layers (Presence,
Dismissal, ScrollLock — those are not morfo).

`Effects` (registered by the runtime on mount) listen for source changes and
apply the derived attrs via `dom.apply`.

`EngineSemantic` receives the occurrence from `runtime.trigger`. It mints the
id, runs the channels' `prepare` hooks and dispatches the signal to ALL
registered channels — all of it synchronously, before `emit` returns its
`{ id, settled }` handle. The built-in `VisualChannel` projects `data-event-*`
through `SignalProjector`, holds the attrs for the configured `hold`, lets the
expression finish, cleans them up and only then resolves `settled`. Nobody
waits for that window: the signal precedes the structural commit, it does not
gate it. Non-visual channels (sound, haptic) are fire-and-forget.

`ADom` only applies the subsequent structural commit. It does not interpret.
Sema and ADom are sibling layers: the engine no longer depends on ADom.

### The `runtime.trigger(eventName)` sequence

```
1. imperative prewrite (transient markers like data-last-action)
2. events.emit(event)  → { id, settled }, dispatched, NOT awaited
3. the provider's synchronous handler mutates state — same tick
4. the render bag re-derives structural attrs (data-state, aria-*) and
   Svelte renders them
```

The signal precedes the commit; it does not gate it (D-full, 2026-09-15). Step 2
used to be awaited, which meant the state changed only after the ~240 ms hold.

The handler mutates state. The effects see the change and rewrite the DOM.
ADom is the only writer of mutable attrs.

### Three Soma scenarios

```ts
// Structural change without a signal
provider.commitState(change);
// internally: dom.apply(change)

// Structural change with a signal
provider.commitState(change, event);
// internally: events.emit(event); dom.apply(change) — same tick, in that order

// Signal without structural change
provider.emitEvent(event);
// internally: void events.emit(event)
```

### Operational rules

- What `dom.apply` writes, Svelte does not render. `partProps` only emits
  static identity (id, marker, ref).
- `events` handlers are synchronous. Async goes outside the trigger.
- Guards (`if (disabled) return`) live at the call-site, not inside the
  handler — if they reach the handler, a perceptual signal was already
  emitted.
- `Sema` and `ADom` are sibling layers: neither depends on the other.
- `morfo.events.commits` is descriptive: it documents the observable, it does
  not execute it. The real causal chain is handler → state → effect.

---

## 3. What makes UIX different

### 3.1 The structural contract is its own layer

In most libraries the component's public structure is scattered:

- attributes in the provider
- roles in the render
- parts in CSS
- selector names in docs
- contracts in tests

UIX concentrates that in `Morfo`. That enables:

- docs derived from the contract
- cross-layer validation (the eidos linter)
- less drift between headless and visual
- more reliable tooling

### 3.2 Semantics never mix with execution

UIX separates the **name of the occurrence** from its **modal
materialization**. Sound, vibration, CSS and future engines use the same
vocabulary without being glued to each other.

### 3.3 Headless behavior doesn't carry every modality

`Soma` is not a mega-engine that knows everything. It doesn't play WAVs or
haptic feedback, and it doesn't decide each channel's perceptual physics.
Soma emits. Channels execute.

### 3.4 The active DOM is app infrastructure

UIX recognizes there are cross-cutting DOM facts several consumers want to
listen to, which is why it introduces `adom` as an app service.

The rule is not "all DOM access goes through ADom". The rule is more precise:
UIX-managed writes, `document/window` listeners, global queries, observers
(`ResizeObserver`, `MutationObserver`, `IntersectionObserver`) and
cross-cutting imperative actions go through `ActiveDom`. That includes focus
and imperative scroll (`focus`, `scrollTo`, `scrollIntoView`,
`scrollWindowTo`). Local reads of an element the component already owns
(`contains`, `closest`, `getBoundingClientRect`, `scrollTop`) stay in the
component.

### 3.5 The app composes services, not "super components"

`active-app` lets the application compose `langs`, `dom`, `clipboard`,
`format`, `events`, and `ActiveUix` delivers them to layer scopes (`Soma`,
`Eidos`) instead of forcing every component to know the full active root.

---

## 4. What UIX is not

UIX is not:

- a flat collection of visual components
- a mere opinionated wrapper over existing primitives
- a classic design system where visuals, behavior and contracts live together
- a monolithic event service that executes every modality
- a global `EventEmitter` dressed up as architecture

UIX's originality is not in inventing exotic names, but in **separating real
problems** that other systems usually accept as a single block.

---

## 5. Dependency rules

```text
Morfo            → declares contracts
SomaRuntime      → interprets morfo inside Soma
Provider         → supplies sources, targets, handlers
Effects          → sync state → attrs
EngineSemantic   → registry + prepare/dispatch of signals to channels
VisualChannel    → prepares data-event* via SignalProjector + holds
SignalProjector  → projects data-event* via uix.dom
ADom             → applies DOM mutations (the structural commit)
Eidos            → materializes visually by reading the DOM
App              → composes services
```

Hard rules:

- `Morfo` knows neither `Soma` nor any runtime code
- `SomaRuntime` reads `Morfo` and depends on `Sema`
- `Provider` does not write mutable attrs to the DOM directly; it supplies
  them as sources to the runtime
- `EngineSemantic` does not mutate the DOM directly; it only orchestrates
  channel hooks
- `VisualChannel.prepare()` delegates DOM projection to a `SignalProjector`
- `DomSignalProjector` writes through the `ActiveDom` received from
  `ActiveUix`
- `Sema` and `ADom` are sibling layers
- `ADom` knows neither `Morfo`, nor `Sema`, nor `Soma`, nor `Eidos`; it only
  executes the mutations, listeners and cross-cutting DOM actions it receives
- `ActiveEidos` adapts `ActiveUix` for visual components; wrappers do not
  import `getActiveUix()` directly
- `Eidos` consumes DOM and `data-*`, not `Soma`/`Sema` internals
- What `dom.apply` writes, Svelte does not render

### The 2-of-3 rule for extending Morfo

A Morfo extension is only justified when **at least two of the three layers**
(soma, sema, eidos) consume it. If only soma benefits, the pattern is a
virtual prop on the provider — do not extend the contract.

| Extension               | Soma           | Sema             | Eidos                    | In morfo |
| ----------------------- | -------------- | ---------------- | ------------------------ | -------- |
| `parts[].archetype`     | ✅ emit        | ✅ verbs by role | ✅ transversal selectors | ✅       |
| `events[].semantic`     | ✅ payload     | ✅ vocabulary    | ✅ tinting               | ✅       |
| `events[].prewrite`     | ✅ executes    | ✅ sequence      | ✅ exit tinting          | ✅       |
| `firstOf` value source  | ✅ only        | —                | —                        | ❌       |
| `prop-not-nullish` cond | ✅ only        | —                | —                        | ❌       |
| Field-context OR        | — virtual prop | —                | —                        | ❌       |

### Canonical cross-layer vocabularies

- **Archetypes**: the cross-component part classification. Defined in
  `src/uix/morfo/types.ts:ARCHETYPE_VOCABULARY`. Emitted as
  `data-archetype="..."` by `runtime.partProps`.
- **Verbs**: the canonical action verbs for `morfo.events[].name`. Defined in
  `src/uix/sema/verbs.ts:SEMA_VERBS`. Name convention:
  `{family}-{verb}[-{nuance}]` (e.g. `commit-save`, `emerge-dismiss-escape`).
  The family prefix is mandatory — `validateMorfo` throws without it.

---

## 6. The difference in one sentence

> Morfo declares, SomaRuntime transcribes, Provider supplies, the render bag
> derives, Sema emits, ADom applies the prewrite, Eidos reads.

Seven pieces, seven responsibilities, none invades the next.

---

## 7. Suggested reading order

0. [`CANON.md`](../CANON.md) — the **semantic canon**: the vocabulary
   (families, intents, verbs, composition, channels) anchored to the book +
   code. The source of truth everything else links.
1. [`architecture/morfo.md`](./morfo.md) — declaration, archetypes, the
   2-of-3 rule
2. [`architecture/sema.md`](./sema.md) — the `emit`
   contract, canonical verbs, channels
3. [`architecture/eidos.md`](./eidos.md) — what eidos
   consumes from the DOM + wrappers
4. [`SOMA_ARCHITECTURE.md`](./soma-architecture.md) — the
   runtime that transcribes morfo
5. [`component-guide.md`](../guides/component-guide.md) — the
   operational guide to create/migrate components
6. [`src/arts/adom/README.md`](../../src/arts/adom/README.md) — `dom.apply`
7. [`architecture/active-uix.md`](./active-uix.md) — the composition root