Doc/chapter 5/update materials

projects/starters/chapter_05/lib/async/async_sample_1.dart

@@ -0,0 +1,48 @@
+import "dart:async";
+
+Future<String> myLongRunningFunction() => Future.delayed(
+ Duration(seconds: 3),
+ () {
+ print("Inside the future");
+ throw Exception("No internet connection!");
+ return "Hello in the future!";
+ },
+ );
+
+void main() {
+ print("Starting main");
+ var futureResult = myLongRunningFunction();
+ print("Immediate result: $futureResult");
+ futureResult
+ .then(
+ (result) {
+ print("Result of function: $result");
+ },
+ )
+ .timeout(
+ Duration(
+ seconds: 1,
+ ),
+ )
+ .catchError(
+ (error) {
+ print("Caught TimeoutException error: $error");
+ },
+ test: (e) => e is TimeoutException,
+ )
+ .catchError(
+ (error) {
+ print("Caught String error: $error");
+ },
+ test: (e) => e is String,
+ )
+ .whenComplete(() {
+ print("Inside whenComplete");
+ });
+ var i = 0;
+ /*while(true){
+ for (int j = 0; j < 1000; j++)
+ print("${i++}");
+ } !!FREEZES!!*/
+ print("Ending main");
+}

projects/starters/chapter_05/lib/async/async_sample_2.dart

@@ -0,0 +1,42 @@
+Future<String> myLongRunningFunction() => Future.delayed(
+ Duration(seconds: 3),
+ () {
+ print("Inside the future");
+ throw Exception("No internet connection!");
+ return "Hello in the future!";
+ },
+ );
+
+Future<String> myAsyncFunction() async {
+ await Future.delayed(Duration(seconds: 3));
+ print("Inside the future");
+ throw Exception("No internet connection");
+ return "Hello in the future";
+}
+
+void asyncVoidFunction() async {
+ print("Starting async void function!");
+ await Future.delayed(Duration(seconds: 1));
+ print("Ending async void function!");
+}
+
+void myAsyncTestFunction() async {
+ print("Starting async func");
+ asyncVoidFunction();
+ //await asyncVoidFunction(); //!ERROR! Cannot await void function
+ print("Calling long running function!");
+ try {
+ var result = await myLongRunningFunction();
+ print("Immediate result: $result");
+ } catch (e) {
+ print("Caught error: $e");
+ } finally {
+ print("Inside finally");
+ }
+}
+
+void main() {
+ print("Starting main function!");
+ myAsyncTestFunction();
+ print("Ending main function!");
+}

projects/starters/chapter_05/lib/async/generator_sample_1.dart

@@ -0,0 +1,16 @@
+import "dart:math";
+
+Iterable<int> calculatePrimes() sync* {
+ yield 2;
+ for (int i = 3; true; i++) {
+ if (calculatePrimes()
+ .takeWhile((prime) => prime <= sqrt(i))
+ .every((prime) => i % prime != 0)) {
+ yield i;
+ }
+ }
+}
+
+void main() {
+ calculatePrimes().take(20).forEach(print);
+}

projects/starters/chapter_05/lib/async/generator_sample_2.dart

@@ -0,0 +1,14 @@
+Stream<int> myStreamGeneratorFunction() async* {
+ yield 1;
+ await Future.delayed(Duration(milliseconds: 200));
+ yield 2;
+ await Future.delayed(Duration(milliseconds: 200));
+ yield 3;
+ await Future.delayed(Duration(milliseconds: 200));
+}
+
+void main() async {
+ await for (var value in myStreamGeneratorFunction()) {
+ print(value);
+ }
+}

projects/starters/chapter_05/pubspec.lock

@@ -7,7 +7,7 @@ packages:
  name: async
  url: "https://pub.dartlang.org"
  source: hosted
- version: "2.8.1"
+ version: "2.9.0"
  boolean_selector:
  dependency: transitive
  description:
@@ -21,35 +21,28 @@ packages:
  name: characters
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.1.0"
- charcode:
- dependency: transitive
- description:
- name: charcode
- url: "https://pub.dartlang.org"
- source: hosted
- version: "1.3.1"
+ version: "1.2.1"
  clock:
  dependency: transitive
  description:
  name: clock
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.1.0"
+ version: "1.1.1"
  collection:
  dependency: transitive
  description:
  name: collection
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.15.0"
+ version: "1.16.0"
  fake_async:
  dependency: transitive
  description:
  name: fake_async
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.2.0"
+ version: "1.3.1"
  flutter:
  dependency: "direct main"
  description: flutter
@@ -66,21 +59,28 @@ packages:
  name: matcher
  url: "https://pub.dartlang.org"
  source: hosted
- version: "0.12.10"
+ version: "0.12.12"
+ material_color_utilities:
+ dependency: transitive
+ description:
+ name: material_color_utilities
+ url: "https://pub.dartlang.org"
+ source: hosted
+ version: "0.1.5"
  meta:
  dependency: transitive
  description:
  name: meta
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.7.0"
+ version: "1.8.0"
  path:
  dependency: transitive
  description:
  name: path
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.8.0"
+ version: "1.8.2"
  sky_engine:
  dependency: transitive
  description: flutter
@@ -92,7 +92,7 @@ packages:
  name: source_span
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.8.1"
+ version: "1.9.0"
  stack_trace:
  dependency: transitive
  description:
@@ -113,34 +113,27 @@ packages:
  name: string_scanner
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.1.0"
+ version: "1.1.1"
  term_glyph:
  dependency: transitive
  description:
  name: term_glyph
  url: "https://pub.dartlang.org"
  source: hosted
- version: "1.2.0"
+ version: "1.2.1"
  test_api:
  dependency: transitive
  description:
  name: test_api
  url: "https://pub.dartlang.org"
  source: hosted
- version: "0.4.2"
- typed_data:
- dependency: transitive
- description:
- name: typed_data
- url: "https://pub.dartlang.org"
- source: hosted
- version: "1.3.0"
+ version: "0.4.12"
  vector_math:
  dependency: transitive
  description:
  name: vector_math
  url: "https://pub.dartlang.org"
  source: hosted
- version: "2.1.0"
+ version: "2.1.2"
 sdks:
- dart: ">=2.12.0 <3.0.0"
+ dart: ">=2.17.0-0 <3.0.0"