sma

/// A KV that can be observed for changes to key bindings.
class ObservableKV {
  ObservableKV(this._kv);
  final KV _kv;
  final _listeners = <void Function(String, Object?)>[];

  Stream<(Object, Object?)> observe(String prefix) {
    late final StreamController<(Object, Object?)> controller;

    void listener(String key, Object? value) {

sma

/// A simple key-value store w/persistent sqlite3 database.
class KV {
  KV._(this._db);
  final Database _db;

  static Future<KV> open(String name) async {
    return KV._(sqlite3.open(name)..execute('create table if not exists kv (k text primary key, v jsonb)'));
  }

  Future<Object?> get(String key) async {

sma

/// A simple read-optimized in-memory key-value store w/persistent file-based redo log.
class KV {
  KV._(this._file, this._data);
  final File _file;
  final Map<String, dynamic> _data;

  static Future<KV> open(File file) async {
    final data = <String, dynamic>{};
    if (!file.existsSync()) return KV._(file, data);
    await for (final line in file //

sma

import 'package:flutter/material.dart';

void main() {
  runApp(const App());
}

class App extends StatelessWidget {
  const App({super.key});

  @override

sma

import 'package:flutter/material.dart';

void main() {
  runApp(const App());
}

class App extends StatelessWidget {
  const App({super.key});

  @override

sma

import 'dart:async';

import 'package:flutter/material.dart';

/// See [asyncTask].
typedef Task<T> = Future<T?> Function(bool Function() cancelled);

/// Runs the future returned by [task] and shows a modal waiting dialog after
/// an initial [delay] (default 100 ms) with an optional [label] until the future
/// completes. The [task] is passed a function that returns whether the task

sma

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {

sma

Creating such an editor can be very complicated. The principle is easy, though. Create a notifier that holds your models, observe that notifier and draw the objects accordingly to the models, then modify the model based on the UI interaction.

Here's a model:

class Box {
  Box({
    required this.center,
    required this.size,
    required this.rotation,

required this.color,

sma

So you want Flutter for the web. Sure thing.

Run

dart create -t web fltr_web
cd fltr_web
dart pub get
dart pub add dev:webdev
dart run webdev serve

sma

import 'package:flutter/material.dart';

void main() {
  Forth().run('V: count 5 ! : inc dup @ 1 + ! ; '
      '[ [ text ] count builder [ count inc ] " Increment text button ] '
      'list column app run');
}

typedef Impl = void Function(Forth f);