diff --git a/packages/wyatt_type_utils/.gitignore b/packages/wyatt_type_utils/.gitignore
new file mode 100644
index 00000000..e38f9b0c
--- /dev/null
+++ b/packages/wyatt_type_utils/.gitignore
@@ -0,0 +1,133 @@
+# Miscellaneous
+*.class
+*.lock
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.buildlog/
+.history
+.svn/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/*
+
+# Visual Studio Code related
+.classpath
+.project
+.settings/
+.vscode/*
+!.vscode/settings.json
+!.vscode/extensions.json
+
+# Flutter repo-specific
+/bin/cache/
+/bin/mingit/
+/dev/benchmarks/mega_gallery/
+/dev/bots/.recipe_deps
+/dev/bots/android_tools/
+/dev/docs/doc/
+/dev/docs/flutter.docs.zip
+/dev/docs/lib/
+/dev/docs/pubspec.yaml
+/dev/integration_tests/**/xcuserdata
+/dev/integration_tests/**/Pods
+/packages/flutter/coverage/
+version
+
+# packages file containing multi-root paths
+.packages.generated
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
+.dart_tool/
+.flutter-plugins
+.flutter-plugins-dependencies
+.packages
+.pub-cache/
+.pub/
+build/
+flutter_*.png
+linked_*.ds
+unlinked.ds
+unlinked_spec.ds
+.fvm/
+
+# Android related
+**/android/**/gradle-wrapper.jar
+**/android/.gradle
+**/android/captures/
+**/android/gradlew
+**/android/gradlew.bat
+**/android/local.properties
+**/android/**/GeneratedPluginRegistrant.java
+**/android/key.properties
+**/android/.idea/
+*.jks
+
+# iOS/XCode related
+**/ios/**/*.mode1v3
+**/ios/**/*.mode2v3
+**/ios/**/*.moved-aside
+**/ios/**/*.pbxuser
+**/ios/**/*.perspectivev3
+**/ios/**/*sync/
+**/ios/**/.sconsign.dblite
+**/ios/**/.tags*
+**/ios/**/.vagrant/
+**/ios/**/DerivedData/
+**/ios/**/Icon?
+**/ios/**/Pods/
+**/ios/**/.symlinks/
+**/ios/**/profile
+**/ios/**/xcuserdata
+**/ios/.generated/
+**/ios/Flutter/App.framework
+**/ios/Flutter/Flutter.framework
+**/ios/Flutter/Flutter.podspec
+**/ios/Flutter/Generated.xcconfig
+**/ios/Flutter/app.flx
+**/ios/Flutter/app.zip
+**/ios/Flutter/.last_build_id
+**/ios/Flutter/flutter_assets/
+**/ios/Flutter/flutter_export_environment.sh
+**/ios/ServiceDefinitions.json
+**/ios/Runner/GeneratedPluginRegistrant.*
+
+# Coverage
+coverage/
+
+# Submodules
+!pubspec.lock
+packages/**/pubspec.lock
+
+# Web related
+lib/generated_plugin_registrant.dart
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Exceptions to the above rules.
+!**/ios/**/default.mode1v3
+!**/ios/**/default.mode2v3
+!**/ios/**/default.pbxuser
+!**/ios/**/default.perspectivev3
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+!/dev/ci/**/Gemfile.lock
+!.vscode/extensions.json
+!.vscode/launch.json
+!.idea/codeStyles/
+!.idea/dictionaries/
+!.idea/runConfigurations/
+
+# Omit committing pubspec.lock for library packages; see
+# https://dart.dev/guides/libraries/private-files#pubspeclock.
+pubspec.lock
diff --git a/packages/wyatt_type_utils/.vscode/extensions.json b/packages/wyatt_type_utils/.vscode/extensions.json
new file mode 100644
index 00000000..30cd2233
--- /dev/null
+++ b/packages/wyatt_type_utils/.vscode/extensions.json
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2022 WYATT GROUP
+ * Please see the AUTHORS file for details.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see .
+ */
+
+{
+ "recommendations": [
+ "psioniq.psi-header",
+ "blaugold.melos-code"
+ ]
+}
\ No newline at end of file
diff --git a/packages/wyatt_type_utils/.vscode/launch.json b/packages/wyatt_type_utils/.vscode/launch.json
new file mode 100644
index 00000000..a5f4f148
--- /dev/null
+++ b/packages/wyatt_type_utils/.vscode/launch.json
@@ -0,0 +1,16 @@
+{
+ // Use IntelliSense to learn about possible attributes.
+ // Hover to view descriptions of existing attributes.
+ // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+ "version": "0.2.0",
+ "configurations": [
+ {
+ "name": "Launch Example",
+ "request": "launch",
+ "type": "dart",
+ "cwd": "example/",
+ "program": "lib/main.dart",
+ "flutterMode": "debug"
+ },
+ ]
+}
\ No newline at end of file
diff --git a/packages/wyatt_type_utils/.vscode/settings.json b/packages/wyatt_type_utils/.vscode/settings.json
new file mode 100644
index 00000000..708f5ba6
--- /dev/null
+++ b/packages/wyatt_type_utils/.vscode/settings.json
@@ -0,0 +1,71 @@
+{
+ "psi-header.changes-tracking": {
+ "isActive": true
+ },
+ "psi-header.config": {
+ "blankLinesAfter": 1,
+ "forceToTop": true
+ },
+ "psi-header.lang-config": [
+ {
+ "beforeHeader": [
+ "# -*- coding:utf-8 -*-",
+ "#!/usr/bin/env python3"
+ ],
+ "begin": "###",
+ "end": "###",
+ "language": "python",
+ "prefix": "# "
+ },
+ {
+ "beforeHeader": [
+ "#!/usr/bin/env sh",
+ ""
+ ],
+ "language": "shellscript",
+ "begin": "",
+ "end": "",
+ "prefix": "# "
+ },
+ {
+ "begin": "",
+ "end": "",
+ "language": "dart",
+ "prefix": "// "
+ },
+ {
+ "begin": "",
+ "end": "",
+ "language": "yaml",
+ "prefix": "# "
+ },
+ {
+ "begin": "",
+ "language": "markdown",
+ },
+ ],
+ "psi-header.templates": [
+ {
+ "language": "*",
+ "template": [
+ "Copyright (C) <> WYATT GROUP",
+ "Please see the AUTHORS file for details.",
+ "",
+ "This program is free software: you can redistribute it and/or modify",
+ "it under the terms of the GNU General Public License as published by",
+ "the Free Software Foundation, either version 3 of the License, or",
+ "any later version.",
+ "",
+ "This program is distributed in the hope that it will be useful,",
+ "but WITHOUT ANY WARRANTY; without even the implied warranty of",
+ "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the",
+ "GNU General Public License for more details.",
+ "",
+ "You should have received a copy of the GNU General Public License",
+ "along with this program. If not, see ."
+ ],
+ }
+ ],
+ "dart.runPubGetOnPubspecChanges": false,
+}
\ No newline at end of file
diff --git a/packages/wyatt_type_utils/AUTHORS b/packages/wyatt_type_utils/AUTHORS
new file mode 100644
index 00000000..f9506138
--- /dev/null
+++ b/packages/wyatt_type_utils/AUTHORS
@@ -0,0 +1,8 @@
+# Below is a list of people and organizations that have contributed
+# to this project. Names should be added to the list like so:
+#
+# Name/Organization
+
+Wyatt Group S.A.S
+Hugo Pointcheval
+Malo Léon
\ No newline at end of file
diff --git a/packages/wyatt_type_utils/CHANGELOG.md b/packages/wyatt_type_utils/CHANGELOG.md
new file mode 100644
index 00000000..7ad72ac3
--- /dev/null
+++ b/packages/wyatt_type_utils/CHANGELOG.md
@@ -0,0 +1,3 @@
+# 0.0.1
+
+- TODO: Describe initial release.
diff --git a/packages/wyatt_type_utils/LICENSE b/packages/wyatt_type_utils/LICENSE
new file mode 100644
index 00000000..e72bfdda
--- /dev/null
+++ b/packages/wyatt_type_utils/LICENSE
@@ -0,0 +1,674 @@
+ GNU GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc.
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+ The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works. By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users. We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors. You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+ To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights. Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+ For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received. You must make sure that they, too, receive
+or can get the source code. And you must show them these terms so they
+know their rights.
+
+ Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+ For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software. For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+ Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so. This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software. The systematic
+pattern of such abuse occurs in the area of products for individuals to
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+have designed this version of the GPL to prohibit the practice for those
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+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+ Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary. To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
+
+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ TERMS AND CONDITIONS
+
+ 0. Definitions.
+
+ "This License" refers to version 3 of the GNU General Public License.
+
+ "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+ "The Program" refers to any copyrightable work licensed under this
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+"recipients" may be individuals or organizations.
+
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+in a fashion requiring copyright permission, other than the making of an
+exact copy. The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
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+ A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+ To "propagate" a work means to do anything with it that, without
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+
+ To "convey" a work means any kind of propagation that enables other
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+a computer network, with no transfer of a copy, is not conveying.
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+ An interactive user interface displays "Appropriate Legal Notices"
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+ Additional terms, permissive or non-permissive, may be stated in the
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+ 8. Termination.
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+ You may not propagate or modify a covered work except as expressly
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+ Termination of your rights under this section does not terminate the
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+in a country, would infringe one or more identifiable patents in that
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+ If, pursuant to or in connection with a single transaction or
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+ A patent license is "discriminatory" if it does not include within
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+or that patent license was granted, prior to 28 March 2007.
+
+ Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+ 12. No Surrender of Others' Freedom.
+
+ If conditions are imposed on you (whether by court order, agreement or
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+excuse you from the conditions of this License. If you cannot convey a
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+not convey it at all. For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
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+
+ 13. Use with the GNU Affero General Public License.
+
+ Notwithstanding any other provision of this License, you have
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+ 14. Revised Versions of this License.
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+be similar in spirit to the present version, but may differ in detail to
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+
+ Each version is given a distinguishing version number. If the
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+
+ If the Program specifies that a proxy can decide which future
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+to choose that version for the Program.
+
+ Later license versions may give you additional or different
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+
+ 15. Disclaimer of Warranty.
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+ 16. Limitation of Liability.
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+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
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+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+
+ Copyright (C)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see .
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ Copyright (C)
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+.
\ No newline at end of file
diff --git a/packages/wyatt_type_utils/README.md b/packages/wyatt_type_utils/README.md
new file mode 100644
index 00000000..84de5044
--- /dev/null
+++ b/packages/wyatt_type_utils/README.md
@@ -0,0 +1,79 @@
+
+
+
+
+# Dart - Wyatt Type Utils
+
+
+
+Type Utils for Dart & Flutter.
+
+## Option\
+
+**Option** is a container object which may or may not contain a non-null value. If a **Value** is present, `isPresent()` will return true and `get()` will return the value. Additional methods that depend on the presence or absence of a contained value are provided, such as `orElse()` (return a default value if value not present) and `ifPresent()` (execute a block of code if the value is present).
+
+```dart
+final Option rand = Option.ofNullable(
+ Random().nextBool() ? null : 10,
+);
+
+print(
+ "`rand` is${rand.isNull ? "" : " not"} null, "
+ "so it's value is ${rand.orElse(15)}",
+);
+
+// Ok, `orElse` is equivalent to ?? but the Option is
+// useful for match pattern and other utils accesses.
+rand.match((value) {
+ print('Value is: $value');
+ }, () {
+ print('Rand is null');
+ },
+);
+
+print('`rand` contains 10 ? => ${rand.contains(10)}');
+```
+
+## Result\
+
+**Result** type is coming from functional languages where exceptions are (rightfully) considered a side-effect, and therefore not appropriate to pass domain errors. Mind the difference between different kinds of errors: Some of them belong to domain, others don't.
+
+*E.g. null reference exception or index out of bounds are not related to domain - they rather indicate a defect.*
+
+Either is defined as a generic type with two branches
+- success with **T**
+- failure with **E**
+
+It can appear in two forms, where it contains an object of **Ok**, or where it contains an object of **Err**. It cannot appear in both states at once, or in none of them. Therefore, if one possesses an **Result** instance, it either contains a successfully produced result, or contains an error object.
+
+```dart
+Future> requestTodo() async => Result.tryCatchAsync(
+ () => get('https://jsonplaceholder.typicode.com/todos/1'),
+ (error) => ServerError('Error while getting todo'),
+);
+
+final Result todo1 = await requestTodo();
+// In Flutter:
+todo1.either(buildWidgetWithTodo, buildSizedBox);
+```
diff --git a/packages/wyatt_type_utils/analysis_options.yaml b/packages/wyatt_type_utils/analysis_options.yaml
new file mode 100644
index 00000000..2f4f39c0
--- /dev/null
+++ b/packages/wyatt_type_utils/analysis_options.yaml
@@ -0,0 +1,20 @@
+# Copyright (C) 2022 WYATT GROUP
+# Please see the AUTHORS file for details.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see .
+
+include: package:wyatt_analysis/analysis_options.yaml
+
+analyzer:
+ exclude: "!example/**"
diff --git a/packages/wyatt_type_utils/example/lib/error.dart b/packages/wyatt_type_utils/example/lib/error.dart
new file mode 100644
index 00000000..67008d6d
--- /dev/null
+++ b/packages/wyatt_type_utils/example/lib/error.dart
@@ -0,0 +1,33 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see .
+
+class AppError {
+ final String message;
+
+ const AppError(this.message);
+
+ @override
+ // ignore: no_runtimetype_tostring
+ String toString() => '$runtimeType: $message';
+}
+
+class ServerError extends AppError {
+ ServerError(super.message);
+}
+
+class ClientError extends AppError {
+ ClientError(super.message);
+}
diff --git a/packages/wyatt_type_utils/example/lib/main.dart b/packages/wyatt_type_utils/example/lib/main.dart
new file mode 100644
index 00000000..e905a556
--- /dev/null
+++ b/packages/wyatt_type_utils/example/lib/main.dart
@@ -0,0 +1,63 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see .
+
+import 'dart:math';
+
+import 'package:http/http.dart' as http;
+import 'package:type_utils_example/error.dart';
+import 'package:type_utils_example/todo.dart';
+import 'package:wyatt_type_utils/wyatt_type_utils.dart';
+
+Future get(String url) async {
+ final res = await http.get(Uri.parse(url));
+ final todo = TodoModel.fromJson(res.body);
+ return todo;
+}
+
+Future> requestTodo() async => Result.tryCatchAsync(
+ () => get('https://jsonplaceholder.typicode.com/todos/1'),
+ (error) => ServerError('Error while getting todo'),
+ );
+
+Future> requestBadTodo() async =>
+ Result.tryCatchAsync(
+ () => get('https://jsonplaceholder.typicode.com/todos/123897'),
+ (error) => ServerError('Error while getting todo'),
+ );
+
+Future main() async {
+ final Result todo1 = await requestTodo();
+ todo1.either(print, print);
+
+ final Result todo2 = await requestBadTodo();
+ todo2.either(print, print);
+
+ final Option rand = Option.ofNullable(Random().nextBool() ? null : 10);
+
+ print(
+ "`rand` is${rand.isNull ? "" : " not"} null, "
+ "so it's value is ${rand.orElse(15)}",
+ );
+
+ // Ok, `orElse` is equivalent to ?? but the Option is useful for match pattern
+ rand.match((value) {
+ print('Value is: $value');
+ }, () {
+ print('Rand is null');
+ });
+
+ print('`rand` contains 10 ? => ${rand.contains(10)}');
+}
diff --git a/packages/wyatt_type_utils/example/lib/todo.dart b/packages/wyatt_type_utils/example/lib/todo.dart
new file mode 100644
index 00000000..e5f21752
--- /dev/null
+++ b/packages/wyatt_type_utils/example/lib/todo.dart
@@ -0,0 +1,85 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see .
+
+// ignore_for_file: public_member_api_docs, sort_constructors_first,
+// ignore_for_file: avoid_equals_and_hash_code_on_mutable_classes
+
+import 'dart:convert';
+
+class TodoModel {
+ final int id;
+ final int userId;
+ final String title;
+ final bool completed;
+ TodoModel({
+ required this.id,
+ required this.userId,
+ required this.title,
+ required this.completed,
+ });
+
+ TodoModel copyWith({
+ int? id,
+ int? userId,
+ String? title,
+ bool? completed,
+ }) =>
+ TodoModel(
+ id: id ?? this.id,
+ userId: userId ?? this.userId,
+ title: title ?? this.title,
+ completed: completed ?? this.completed,
+ );
+
+ Map toMap() => {
+ 'id': id,
+ 'userId': userId,
+ 'title': title,
+ 'completed': completed,
+ };
+
+ factory TodoModel.fromMap(Map map) => TodoModel(
+ id: map['id'] as int,
+ userId: map['userId'] as int,
+ title: map['title'] as String,
+ completed: map['completed'] as bool,
+ );
+
+ String toJson() => json.encode(toMap());
+
+ factory TodoModel.fromJson(String source) =>
+ TodoModel.fromMap(json.decode(source) as Map);
+
+ @override
+ String toString() => 'TodoModel(id: $id, userId: $userId, title: '
+ '$title, completed: $completed)';
+
+ @override
+ bool operator ==(covariant TodoModel other) {
+ if (identical(this, other)) {
+ return true;
+ }
+
+ return other.id == id &&
+ other.userId == userId &&
+ other.title == title &&
+ other.completed == completed;
+ }
+
+ @override
+ int get hashCode =>
+ id.hashCode ^ userId.hashCode ^ title.hashCode ^ completed.hashCode;
+}
diff --git a/packages/wyatt_type_utils/example/pubspec.yaml b/packages/wyatt_type_utils/example/pubspec.yaml
new file mode 100644
index 00000000..0562fe59
--- /dev/null
+++ b/packages/wyatt_type_utils/example/pubspec.yaml
@@ -0,0 +1,43 @@
+name: type_utils_example
+description: A new Flutter project.
+
+# The following line prevents the package from being accidentally published to
+# pub.dev using `flutter pub publish`. This is preferred for private packages.
+publish_to: "none" # Remove this line if you wish to publish to pub.dev
+
+# The following defines the version and build number for your application.
+# A version number is three numbers separated by dots, like 1.2.43
+# followed by an optional build number separated by a +.
+# Both the version and the builder number may be overridden in flutter
+# build by specifying --build-name and --build-number, respectively.
+# In Android, build-name is used as versionName while build-number used as versionCode.
+# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
+# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
+# Read more about iOS versioning at
+# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
+version: 1.0.0+1
+
+environment:
+ sdk: ">=2.17.0 <3.0.0"
+
+# Dependencies specify other packages that your package needs in order to work.
+# To automatically upgrade your package dependencies to the latest versions
+# consider running `flutter pub upgrade --major-versions`. Alternatively,
+# dependencies can be manually updated by changing the version numbers below to
+# the latest version available on pub.dev. To see which dependencies have newer
+# versions available, run `flutter pub outdated`.
+dependencies:
+ http: ^0.13.4
+
+ wyatt_type_utils:
+ path: "../"
+
+dev_dependencies:
+ wyatt_analysis:
+ git:
+ url: https://git.wyatt-studio.fr/Wyatt-FOSS/wyatt-packages
+ ref: wyatt_analysis-v2.1.0
+ path: packages/wyatt_analysis
+# For information on the generic Dart part of this file, see the
+# following page: https://dart.dev/tools/pub/pubspec
+
diff --git a/packages/wyatt_type_utils/example/test/widget_test.dart b/packages/wyatt_type_utils/example/test/widget_test.dart
new file mode 100644
index 00000000..1bb8b149
--- /dev/null
+++ b/packages/wyatt_type_utils/example/test/widget_test.dart
@@ -0,0 +1,15 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see .
diff --git a/packages/wyatt_type_utils/example/web/favicon.png b/packages/wyatt_type_utils/example/web/favicon.png
new file mode 100644
index 00000000..8aaa46ac
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diff --git a/packages/wyatt_type_utils/example/web/icons/Icon-192.png b/packages/wyatt_type_utils/example/web/icons/Icon-192.png
new file mode 100644
index 00000000..b749bfef
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diff --git a/packages/wyatt_type_utils/example/web/icons/Icon-512.png b/packages/wyatt_type_utils/example/web/icons/Icon-512.png
new file mode 100644
index 00000000..88cfd48d
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diff --git a/packages/wyatt_type_utils/example/web/icons/Icon-maskable-192.png b/packages/wyatt_type_utils/example/web/icons/Icon-maskable-192.png
new file mode 100644
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diff --git a/packages/wyatt_type_utils/example/web/icons/Icon-maskable-512.png b/packages/wyatt_type_utils/example/web/icons/Icon-maskable-512.png
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diff --git a/packages/wyatt_type_utils/example/web/index.html b/packages/wyatt_type_utils/example/web/index.html
new file mode 100644
index 00000000..41b3bc33
--- /dev/null
+++ b/packages/wyatt_type_utils/example/web/index.html
@@ -0,0 +1,58 @@
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ example
+
+
+
+
+
+
+
+
+
+
diff --git a/packages/wyatt_type_utils/example/web/manifest.json b/packages/wyatt_type_utils/example/web/manifest.json
new file mode 100644
index 00000000..096edf8f
--- /dev/null
+++ b/packages/wyatt_type_utils/example/web/manifest.json
@@ -0,0 +1,35 @@
+{
+ "name": "example",
+ "short_name": "example",
+ "start_url": ".",
+ "display": "standalone",
+ "background_color": "#0175C2",
+ "theme_color": "#0175C2",
+ "description": "A new Flutter project.",
+ "orientation": "portrait-primary",
+ "prefer_related_applications": false,
+ "icons": [
+ {
+ "src": "icons/Icon-192.png",
+ "sizes": "192x192",
+ "type": "image/png"
+ },
+ {
+ "src": "icons/Icon-512.png",
+ "sizes": "512x512",
+ "type": "image/png"
+ },
+ {
+ "src": "icons/Icon-maskable-192.png",
+ "sizes": "192x192",
+ "type": "image/png",
+ "purpose": "maskable"
+ },
+ {
+ "src": "icons/Icon-maskable-512.png",
+ "sizes": "512x512",
+ "type": "image/png",
+ "purpose": "maskable"
+ }
+ ]
+}
diff --git a/packages/wyatt_type_utils/lib/src/either_base.dart b/packages/wyatt_type_utils/lib/src/either_base.dart
new file mode 100644
index 00000000..651132ef
--- /dev/null
+++ b/packages/wyatt_type_utils/lib/src/either_base.dart
@@ -0,0 +1,145 @@
+// // Copyright (C) 2022 WYATT GROUP
+// // Please see the AUTHORS file for details.
+// //
+// // This program is free software: you can redistribute it and/or modify
+// // it under the terms of the GNU General Public License as published by
+// // the Free Software Foundation, either version 3 of the License, or
+// // any later version.
+// //
+// // This program is distributed in the hope that it will be useful,
+// // but WITHOUT ANY WARRANTY; without even the implied warranty of
+// // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// // GNU General Public License for more details.
+// //
+// // You should have received a copy of the GNU General Public License
+// // along with this program. If not, see .
+
+// // ignore_for_file: avoid_positional_boolean_parameters
+
+part 'future_result.dart';
+part 'result.dart';
+part 'option.dart';
+
+mixin _Left on _EitherBase {}
+
+mixin _Right on _EitherBase {}
+
+class _EitherBaseException implements Exception {
+ final String message;
+ const _EitherBaseException(this.message);
+
+ @override
+ String toString() => '_EitherException: $message';
+}
+
+abstract class _EitherBase {
+ const _EitherBase();
+
+ bool get _isLeft => this is _Left;
+
+ bool get _isRight => this is _Right;
+
+ LeftType? get _left => _fold(
+ (value) => value,
+ (right) => null,
+ );
+
+ RightType? get _right => _fold(
+ (left) => null,
+ (value) => value,
+ );
+
+ U _unwrap() {
+ if (U == LeftType) {
+ return _fold(
+ (value) => value,
+ (right) => throw const ResultException(
+ 'Illegal use. You should check left value before calling',
+ ),
+ ) as U;
+ }
+ if (U == RightType) {
+ return _fold(
+ (left) => throw const ResultException(
+ 'Illegal use. You should check right value before calling',
+ ),
+ (value) => value,
+ ) as U;
+ }
+ throw ResultException(
+ 'Illegal use. You should use $LeftType or $RightType type',
+ );
+ }
+
+ Future _unwrapAsync() {
+ if (U == LeftType) {
+ return _foldAsync(
+ Future.value,
+ (right) => throw const ResultException(
+ 'Illegal use. You should check left value before calling',
+ ),
+ ) as Future;
+ }
+ if (U == RightType) {
+ return _foldAsync(
+ (left) => throw const ResultException(
+ 'Illegal use. You should check right value before calling',
+ ),
+ Future.value,
+ ) as Future;
+ }
+ throw ResultException(
+ 'Illegal use. You should use $LeftType or $RightType type',
+ );
+ }
+
+ U _fold(
+ U Function(LeftType left) fnL,
+ U Function(RightType right) fnR,
+ );
+
+ Future _foldAsync(
+ Future Function(LeftType left) fnL,
+ Future Function(RightType right) fnR,
+ );
+
+ _EitherBase _and(
+ _EitherBase res,
+ );
+
+ _EitherBase _or(
+ _EitherBase res,
+ );
+
+ bool _contains(U x);
+
+ LeftType _expect(String msg);
+
+ RightType _expectErr(String msg);
+
+ _EitherBase _map(
+ U Function(LeftType left) mapper,
+ );
+
+ Future<_EitherBase> _mapAsync(
+ Future Function(LeftType left) mapper,
+ );
+
+ _EitherBase _mapErr(
+ F Function(RightType right) mapper,
+ );
+
+ Future<_EitherBase> _mapErrAsync(
+ Future Function(RightType right) mapper,
+ );
+
+ _EitherBase _either(
+ L Function(LeftType left) fnL,
+ R Function(RightType right) fnR,
+ );
+
+ Future<_EitherBase> _eitherAsync(
+ Future Function(LeftType left) fnL,
+ Future Function(RightType right) fnR,
+ );
+}
diff --git a/packages/wyatt_type_utils/lib/src/future_result.dart b/packages/wyatt_type_utils/lib/src/future_result.dart
new file mode 100644
index 00000000..95f8942f
--- /dev/null
+++ b/packages/wyatt_type_utils/lib/src/future_result.dart
@@ -0,0 +1,108 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see .
+
+part of 'either_base.dart';
+
+extension FutureResult on Future> {
+ /// Represents the left side of [Result] class.
+ Future get isOk => then((result) => result.isOk);
+
+ /// Represents the right side of [Result] class.
+ Future get isErr => then((result) => result.isErr);
+
+ /// Get [U] value, may throw an exception.
+ Future unwrap() => then((result) => result.unwrap());
+
+ /// Get **async** [U] value, may throw an exception.
+ ///
+ /// With nullable, `Future(Future(U)) == Future(U)`
+ Future unwrapAsync() => then((result) => result.unwrapAsync());
+
+ /// Fold [Ok] and [Err] into the value of one type
+ Future fold(
+ U Function(T value) valueTransformer,
+ U Function(E error) errorTransformer,
+ ) =>
+ then((result) => result.fold(valueTransformer, errorTransformer));
+
+ /// Fold [Ok] and [Err] **asynchronously** into the value of one type
+ Future foldAsync(
+ Future Function(T value) valueTransformer,
+ Future Function(E error) errorTransformer,
+ ) =>
+ then((result) => result.foldAsync(valueTransformer, errorTransformer));
+
+ /// Swap [Ok] and [Err]
+ Future> swap() => then((result) => result.swap());
+
+ /// Returns [res] if the [Result] is [Ok], otherwise returns
+ /// the [Err] value of this.
+ Future> and(Result res) =>
+ then((result) => result.and(res));
+
+ /// Returns [res] if the [Result] is [Err], otherwise returns
+ /// the [Ok] value of this.
+ Future> or(Result res) =>
+ then((result) => result.or(res));
+
+ /// Returns true if the result is an [Ok] or [Err] value containing
+ /// the given value/error.
+ Future contains(U x) => then((result) => result.contains(x));
+
+ /// Returns the contained [Ok] value. Throw [ResultException] on [Err] with
+ /// its content.
+ Future expect(String msg) => then((result) => result.expect(msg));
+
+ /// Returns the contained [Err] value. Throw [ResultException] on [Ok] with
+ /// its content.
+ Future expectErr(String msg) => then((result) => result.expectErr(msg));
+
+ /// Maps a [Result] to [Result] by applying a function to a
+ /// contained [Ok] value, leaving an [Err] value untouched.
+ Future> map(U Function(T value) mapper) =>
+ then((result) => result.map(mapper));
+
+ /// Maps a [Result] to [Result] by applying an **async** function
+ /// to a contained [Ok] value, leaving an [Err] value untouched.
+ Future> mapAsync(Future Function(T value) mapper) =>
+ then((result) => result.mapAsync(mapper));
+
+ /// Maps a [Result] to [Result] by applying a function to a
+ /// contained [Err] value, leaving an [Ok] value untouched.
+ Future> mapErr(F Function(E error) mapper) =>
+ then((result) => result.mapErr(mapper));
+
+ /// Maps a [Result] to [Result] by applying an **async** function
+ /// to a contained [Err] value, leaving an [Ok] value untouched.
+ Future> mapErrAsync(Future Function(E error) mapper) =>
+ then((result) => result.mapErrAsync(mapper));
+
+ /// Transforms a [Result] to [Result] by applying functions to
+ /// contained [Ok] and [Err] values.
+ Future> either(
+ U Function(T value) valueTransformer,
+ F Function(E error) errorTransformer,
+ ) =>
+ then((result) => result.either(valueTransformer, errorTransformer));
+
+ /// Transforms a [Result] to [Result] by applying **async**
+ /// functions to contained [Ok] and [Err] values.
+ Future> eitherAsync(
+ Future Function(T value) valueTransformer,
+ Future Function(E error) errorTransformer,
+ ) =>
+ then((result) => result.eitherAsync(valueTransformer, errorTransformer));
+}
diff --git a/packages/wyatt_type_utils/lib/src/option.dart b/packages/wyatt_type_utils/lib/src/option.dart
new file mode 100644
index 00000000..b86a510b
--- /dev/null
+++ b/packages/wyatt_type_utils/lib/src/option.dart
@@ -0,0 +1,301 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see .
+
+part of 'either_base.dart';
+
+/// {@template option_exception}
+/// [OptionException] is sometimes threw by [Option] objects.
+///
+/// ```dart
+/// throw OptionException('Emergency failure!');
+/// ```
+/// {@endtemplate}
+class OptionException extends _EitherBaseException {
+ /// {@macro result_exception}
+ const OptionException(super.message);
+
+ @override
+ String toString() => 'OptionException: $message';
+}
+
+/// {@template option}
+/// [Option] is a container object which may or may not contain a non-null
+/// value. If a [Value] is present, isPresent() will return true and get()
+/// will return the value.
+///
+/// Additional methods that depend on the presence or absence of
+/// a contained value are provided, such as orElse() (return a default value
+/// if value not present) and ifPresent() (execute a block of code if the
+/// value is present).
+/// {@endtemplate}
+abstract class Option extends _EitherBase {
+ /// {@macro option}
+ const Option._();
+
+ /// Represents the left side of [Option] class.
+ bool get isPresent => _isLeft;
+
+ /// Represents the right side of [Option] class.
+ bool get isNull => _isRight;
+
+ /// Get nullable [Value].
+ T? get() => _left;
+
+ /// Get [U] value, may throw an exception.
+ U unwrap() => _unwrap();
+
+ /// Get **async** [U] value, may throw an exception.
+ Future unwrapAsync() => _unwrapAsync();
+
+ /// Match [Value] and [None].
+ void match(
+ void Function(T value) value,
+ void Function() none,
+ ) =>
+ _fold(
+ (left) => value(left),
+ (right) => none(),
+ );
+
+ /// Match **async** [Value] and [None].
+ Future matchAsync(
+ Future Function(T value) value,
+ Future Function() none,
+ ) =>
+ _foldAsync(
+ (left) => value(left),
+ (right) => none(),
+ );
+
+ /// If [Value] is present, invoke the specified consumer
+ /// with the value, otherwise do nothing.
+ void ifPresent(
+ void Function(T value) consumer,
+ ) =>
+ _fold(
+ (left) => consumer(left),
+ (right) => {},
+ );
+
+ /// Return the [Value] if present, otherwise return [other].
+ T orElse(
+ T other,
+ ) =>
+ _fold(
+ (left) => left,
+ (right) => other,
+ );
+
+ /// Return the [Value] if present, otherwise call and return result
+ /// of [supplier].
+ T orElseLazy(
+ T Function() supplier,
+ ) =>
+ _fold(
+ (left) => left,
+ (right) => supplier(),
+ );
+
+ /// Returns [res] if the [Option] is [Value], otherwise returns
+ /// the [None] value of this.
+ Option and(Option res) => _and(res) as Option;
+
+ /// Returns [res] if the [Option] is [None], otherwise returns
+ /// the [Value] of this.
+ Option or(Option res) => _or(res) as Option;
+
+ /// Returns true if the result is a [Value].
+ bool contains(U x) => _contains(x);
+
+ /// Returns the contained [Value]. Throw [OptionException] on [None].
+ T expect(String msg) => _expect(msg);
+
+ /// Maps a [Option] to [Option] by applying a function to a
+ /// contained [Value].
+ Option map(U Function(T value) mapper) => _map(mapper) as Option;
+
+ /// Maps a [Option] to [Option] by applying an **async** function
+ /// to a contained [Value].
+ Future> mapAsync(Future Function(T value) mapper) async =>
+ await _mapAsync(mapper) as Option;
+
+ /// Constructs an [Option] with the specified present non-null [Value].
+ static Value of(T value) {
+ if (value == null) {
+ throw const OptionException("Value can' be null. Use `ofNullable()`");
+ }
+ return ofNullable(value) as Value;
+ }
+
+ /// Constructs an [Option] describing the specified [Value],
+ /// if non-null, otherwise returns a [None].
+ static Option ofNullable(T? value) {
+ if (value != null) {
+ return Value(value);
+ } else {
+ return None();
+ }
+ }
+
+ /// Constructs an [Option] with the specified present non-null [Value].
+ static Value ofLazy(T Function() value) {
+ final v = value();
+ if (v == null) {
+ throw const OptionException("Value can' be null. Use `ofNullableLazy()`");
+ }
+ return ofNullable(v) as Value;
+ }
+
+ /// Constructs an [Option] describing the specified [Value],
+ /// if non-null, otherwise returns a [None].
+ static Option ofNullableLazy(T? Function() value) {
+ final v = value();
+ if (v != null) {
+ return Value(v);
+ } else {
+ return None();
+ }
+ }
+}
+
+class Value extends Option with _Left {
+ final T value;
+
+ /// {@macro ok}
+ const Value(this.value) : super._();
+
+ @override
+ _EitherBase _and(_EitherBase res) => res as Option;
+
+ @override
+ bool _contains(U x) => value == x;
+
+ @override
+ _EitherBase _either(
+ L Function(T left) fnL,
+ R Function(void right) fnR,
+ ) =>
+ throw UnimplementedError();
+
+ @override
+ Future<_EitherBase> _eitherAsync(
+ Future Function(T left) fnL,
+ Future Function(void right) fnR,
+ ) =>
+ throw UnimplementedError();
+
+ @override
+ T _expect(String msg) => value;
+
+ @override
+ void _expectErr(String msg) => throw UnimplementedError();
+
+ @override
+ U _fold(U Function(T left) fnL, U Function(void right) fnR) => fnL(value);
+
+ @override
+ Future _foldAsync(
+ Future Function(T left) fnL,
+ Future Function(void right) fnR,
+ ) =>
+ fnL(value);
+
+ @override
+ _EitherBase _map(U Function(T left) mapper) =>
+ Value(mapper(value));
+
+ @override
+ Future<_EitherBase> _mapAsync(
+ Future Function(T left) mapper,
+ ) =>
+ mapper(value).then(Value.new);
+
+ @override
+ _EitherBase _mapErr(F Function(void right) mapper) =>
+ throw UnimplementedError();
+
+ @override
+ Future<_EitherBase> _mapErrAsync(
+ Future Function(void right) mapper,
+ ) =>
+ throw UnimplementedError();
+
+ @override
+ _EitherBase _or(_EitherBase res) => this as _EitherBase;
+}
+
+class None extends Option with _Right {
+ /// {@macro ok}
+ const None() : super._();
+
+ @override
+ _EitherBase _and(_EitherBase res) => this as Option;
+
+ @override
+ bool _contains(U x) => false;
+
+ @override
+ _EitherBase _either(
+ L Function(T left) fnL,
+ R Function(void right) fnR,
+ ) =>
+ throw UnimplementedError();
+
+ @override
+ Future<_EitherBase> _eitherAsync(
+ Future Function(T left) fnL,
+ Future Function(void right) fnR,
+ ) =>
+ throw UnimplementedError();
+
+ @override
+ T _expect(String msg) => throw OptionException(msg);
+
+ @override
+ void _expectErr(String msg) => throw UnimplementedError();
+
+ @override
+ U _fold(U Function(T left) fnL, U Function(void right) fnR) => fnR(null);
+
+ @override
+ Future _foldAsync(
+ Future Function(T left) fnL,
+ Future Function(void right) fnR,
+ ) =>
+ fnR(null);
+
+ @override
+ _EitherBase _map(U Function(T left) mapper) => None();
+
+ @override
+ Future<_EitherBase> _mapAsync(
+ Future Function(T left) mapper,
+ ) =>
+ Future.value(None());
+
+ @override
+ _EitherBase _mapErr(F Function(void right) mapper) =>
+ throw UnimplementedError();
+
+ @override
+ Future<_EitherBase> _mapErrAsync(
+ Future Function(void right) mapper,
+ ) =>
+ throw UnimplementedError();
+
+ @override
+ _EitherBase _or(_EitherBase res) => res;
+}
diff --git a/packages/wyatt_type_utils/lib/src/result.dart b/packages/wyatt_type_utils/lib/src/result.dart
new file mode 100644
index 00000000..4756f970
--- /dev/null
+++ b/packages/wyatt_type_utils/lib/src/result.dart
@@ -0,0 +1,327 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see .
+
+// ignore_for_file: avoid_positional_boolean_parameters
+
+part of 'either_base.dart';
+
+/// {@template result_exception}
+/// [ResultException] is sometimes threw by [Result] objects.
+///
+/// ```dart
+/// throw ResultException('Emergency failure!');
+/// ```
+/// {@endtemplate}
+class ResultException extends _EitherBaseException {
+ /// {@macro result_exception}
+ const ResultException(super.message);
+
+ @override
+ String toString() => 'ResultException: $message';
+}
+
+/// {@template result}
+/// [Result] type is coming from functional languages where exceptions are
+/// (rightfully) considered a side-effect, and therefore not appropriate to
+/// pass domain errors. Mind the difference between different kinds of errors:
+/// Some of them belong to domain, others don't.
+///
+/// *E.g. null reference exception or index out of bounds
+/// are not related to domain - they rather indicate a defect.*
+///
+/// Either is defined as a generic type with two branches
+/// - success with [T]
+/// - failure with [E]
+///
+/// It can appear in two forms, where
+/// it contains an object of [Ok], or where it contains an object
+/// of [Err]. It cannot appear in both states at once, or in none of them.
+/// Therefore, if one possesses an [Result] instance, it either contains a
+/// successfully produced result, or contains an error object.
+/// {@endtemplate}
+abstract class Result extends _EitherBase {
+ /// {@macro result}
+ const Result._();
+
+ /// Represents the left side of [Result] class.
+ bool get isOk => _isLeft;
+
+ /// Represents the right side of [Result] class.
+ bool get isErr => _isRight;
+
+ /// Get nullable [Ok] value, and discarding the error, if any.
+ T? get ok => _left;
+
+ /// Get nullable [Err] value, and discarding the success value, if any.
+ E? get err => _right;
+
+ /// Get [U] value, may throw an exception.
+ U unwrap() => _unwrap();
+
+ /// Get **async** [U] value, may throw an exception.
+ Future unwrapAsync() => _unwrapAsync();
+
+ /// Fold [Ok] and [Err] into the value of one type
+ U fold(
+ U Function(T value) valueTransformer,
+ U Function(E error) errorTransformer,
+ ) =>
+ _fold(
+ (left) => valueTransformer(left),
+ (right) => errorTransformer(right),
+ );
+
+ /// Fold [Ok] and [Err] **asynchronously** into the value of one type
+ Future foldAsync(
+ Future Function(T value) valueTransformer,
+ Future
+
+ 