kikuchy

package com.example.nfcftest

import android.nfc.NfcAdapter
import android.nfc.Tag
import android.nfc.tech.NfcF
import android.os.Bundle
import android.util.Log
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.Arrangement

kikuchy

type Broadcaster[T any] struct {
	chans []chan T
}

func (b *Broadcaster[T]) Listen() chan T {
	c := make(chan T)
	b.chans = append(b.chans, c)
	return c
}

kikuchy

import "sync"

type JobQueue struct {
    limit   int
    wg      sync.WaitGroup
    mu      sync.Mutex
    running int
    waiting []func()
}

kikuchy

enum $NAME$ {
  $V1$,
  $V2$,
}

extension $NAME$X on $NAME$ {
  T when<T>({
    required T Function() $V1$,
    required T Function() $V2$,
  }) {

kikuchy

// https://gist.github.com/kikuchy/d96a45d0b22b0baa437ccca69ad6679b

import 'dart:async';

typedef Combinator<T1, T2, R> = R Function(T1, T2);

Stream<R> combineLatestN<R>(
    List<Stream<dynamic>> streams, R Function(List<dynamic>) combinator) {
  final combined = StreamController<R>();
  final subscriptions = <StreamSubscription>{};

kikuchy

import "package:flutter/material.dart";

final VoidCallback? nullableFunction = null;
final Map<String, String>? nullableMap = null;

void main() {
  // これはnon-null
  final int a = 1;

  // なのでこれは静的型検査でエラーになる

kikuchy

enum ColorExpression {
  rgb,
  cymk,
}

abstract class ColorValue {
  ColorExpression get expression;
}

class RgbColor extends ColorValue {

kikuchy

enum Hoge {
  hoge, fuga, moge, piyo,
}

void main() {
  Set s = {
    for (Hoge h in Hoge.values)
      if (h != Hoge.hoge) h
  };
  print(s);

kikuchy

import "dart:async";
void main() async {
  final job = Future.delayed(Duration(seconds: 2), () => print("ended"));
  final completer = Completer()..complete(job);
  print(completer.isCompleted);		// fal....true!?!?!?
  await job;
  print(completer.isCompleted);		// true, of course.
}

kikuchy

void main() {
  Future(() => throw Exception())
    .then((i) => print(i),
          // Statically, no issues found. But it causes RUNTIME error 👇
          // 
          // Uncaught Error: TypeError: Closure 'main_closure1': type '() => void' is not a subtype of type '(Object) => dynamic'
          onError: () => print("foo"));
  
  Future(() => throw Exception())
    .then((i) => print(i),