crepuscularity-flutter #

Naming: the package directory, the crepus flutter CLI, and all docs use the hyphenated crepuscularity-flutter, matching the sibling crates (crepuscularity-native, crepuscularity-gpui, …). The one exception is the Dart pubspec.yaml name: field, which must be crepuscularity_flutter because pub.flutter-io.cn names cannot contain hyphens (^[a-z][a-z0-9_]*$). The import and the dependency key in a consumer's pubspec.yaml therefore also use the underscore form — that is the pub package name, not an inconsistency.

Flutter runtime renderer for Crepuscularity — the Flutter counterpart to the SwiftUI and Jetpack Compose native shells in examples/native-shells. It turns Crepuscularity UI into Flutter widgets, from either the View IR wire format or .crepus source parsed in pure Dart (no Rust round-trip).

Usage #

import 'package:crepuscularity_flutter/crepuscularity_flutter.dart';

// From decoded View IR JSON ({ version, root: [...] }).
CrepusView.fromIr(irMap, onAction: (action) => handle(action));

// From .crepus source, rendered directly.
CrepusView.fromSource('''
stack col gap-2
  text font-semibold "Reminder"
  text text-sm "Pay rent tomorrow"
  button "Do it now" onclick=prompt:Draft a rent reminder
''', onAction: (action) => handle(action));

Both entry points produce the same widget tree; fromSource(x) and fromIr(lower(x)) agree on the shared fixtures (see test/conformance_test.dart).

Vocabulary #

Constrained, non-executing subset of the View IR ViewNode kinds (crates/crepuscularity-native/src/ir.rs):

text, stack (row/column, Tailwind-ish spacing/alignment), scroll, button, toggle, checkbox, progress, meter, badge, divider, spacer, image, if, forEach, list, listItem.

Anything outside the allowlist (webView, filePicker, dropzone, free input/picker/slider, tabs, slot, …) renders nothing — it never throws.

Action model #

The package is generic and action-agnostic. on_click / on_change / on_long_press strings are surfaced verbatim to the host via onAction; the package never interprets, maps, or evaluates an action. The host owns action policy (whitelisting, URL safety, etc.). There is no eval anywhere.

Caps #

CrepusLimits bounds node count (default 60), depth (8), and source length (8000). Oversized input yields an empty document, gracefully.

Distribution #

This package is designed to be consumed as a published dependency, fetched and pinned via the crepus flutter CLI affordance (see crates/crepuscularity-cli). Until it is published, host apps pin it with a git dependency on this repo (git: { url, ref, path: plugins/flutter }).