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 }).