Merge pull request #879 from unoplatform/dev/dr/docsModel

docs(feed): Doc for 2.3 release

doc/Overview/Reactive/in-apps.md

@@ -3,24 +3,23 @@ uid: Overview.Reactive.InApps
 ---
 # Usage in applications of feeds
 
-The recommended use for feeds is only in view models.
+The recommended use for feeds is only in models.
 
-The reactive framework allows you to design state-less view models, focusing on the presentation logic. 
-Your view models only have to request in their constructors the user _ inputs_ that are expected from the view. Inputs could be:
-* An `IInput<T>` to get _data_ from the view (e.g. for 2-way bindings);
-* An `ICommandBuilder` for the "trigger" inputs.
-
-In order to easily interact with the binding engine in a performant way, a `BindableXXX` class is automatically generated. It is this class that will hold the state and which **has to be set as `DataContext` of your page**.
+The Reactive framework allows you to design state-less _models_, focusing on the presentation logic. 
+They are expected to expose some `IFeed`, `IListFeed`, `IState` or `IListState`.
+A bindable friendly and higly performant _view model_ is then automatically generated by the Reactive framework.
+It is this class that will hold the state and which **has to be set as `DataContext` of your page**.
 
 > [!NOTE]
-> The bindable counterpart of a class will be created when the class name ends with "ViewModel".
-> You can customize that behavior using the `[ReactiveBindable]` attribute.
+> The _ViewModel_ of a _model_ is created when the class name matches the regex "Model$".
+> You can customize that behavior using the `[ImplicitBindables("MyApp\.Presentation\.\.*Model$")]` on the assembly
+> or the `[ReactiveBindable]` attribute on you model itself.
 
 > [!NOTE]
-> For easier View Model creation, public properties will also be accessible on the `BindableXXX` class. 
-> You can also access the view model itself through the `Model` property.
+> To ease _models_ declaration, public properties are also accessible on the _view model_ class. 
+> You can also access the model itself through the `Model` property.
 
-## Display some data in the UI (VM to View)
+## Display some data in the UI (Model to View)
 
 To render a _feed_ in the UI, you only have to expose it through a public property:
 ```csharp
@@ -131,11 +130,64 @@ so you can enhance the UX of the pagination, like display a loading indicator wh
 </uer:FeedView>
 ```
 
+## Selection
+
+The reactive framework has embedded support of selected item of a `ListFeed` data-bound to a `Selector`, like the `ListView`.
+It is not required to data-bind (and synchronize) the `ListView.SelectedItem`, it will instead be automatically pushed from and to the view.
+
+```xml
+<uer:FeedView Source="{Binding Items}">
+	<DataTemplate>
+		<ListView ItemsSource="{Binding Data}" />
+	</DataTemplate>
+</uer:FeedView>
+```
+
+And in the model:
+
+```csharp
+public IListState<int> Items => ListView
+	.Value(this, () => ImmutableList.Create(1, 2, 3, 4, 5))
+	.Selection(SelectedItem);
+
+public IState<int> SelectedItem => State.Value(this, () => 3);
+```
+
+### Project selected item into another entity
+
+It is possible to synchronize the selected item _key_ into another aggregate root object, for instance, assuming `Profile` and `Country` records:
+
+```csharp
+public record Profile(string? FirstName, string? CountryId);
+
+public record Country(string Id, string Name);
+```
+
+The selected item automatically stored into the `Profile.CountyId` by doing:
+```csharp
+public IState<Profile> Profile => State.Async(this, _svc.GetProfile);
+
+public IListState<Country> Countries => ListState
+	.Async(this, _svc.GetCountries)
+	.Selection(Profile, p => p.CountryId);
+```
+
+```xml
+<uer:FeedView Source="{Binding Countries}">
+	<DataTemplate>
+		<ComboBox ItemsSource="{Binding Data}" />
+	</DataTemplate>
+</uer:FeedView>
+```
+
+> [!NOTE]
+> As the `IState<Porfile> Profile` state might be `None` when an item is being selected, the `Profile` class 
+> must have either a parameter-less contructor, either a constructor that accepts only nullable parameters.
 
 ## Commands
-The generated bindable counterpart of a class will automatically re-expose as `ICommand` public methods that are compatible (cf. "general rules" below).
+The generated _view model_ of a _model_ will automatically re-expose as `ICommand` public methods that are compatible (cf. "general rules" below).
 
-For instance, in your ViewModel:
+For instance, in your _model_:
 
 ```csharp
 public async ValueTask Share() 
@@ -152,7 +204,7 @@ This will be exposed into an `ICommand` that can be data-bound to the `Command`
 
 By default, if the method has a parameter `T myValue` and there is a property `Feed<T> MyValue` on the same class (matching type and name), that parameter will automatically be filled from that feed.
 
-For instance, in your ViewModel:
+For instance, in your _model_:
 
 ```csharp
 public IFeed<string> Message { get; }

src/Uno.Extensions.Core.Generators/Common/Extensions/StringExtensions.cs

@@ -113,4 +113,9 @@ public static string Replace(this string text, char[] chars, char replacement)
 
 		return result.ToString();
 	}
+
+	public static string TrimEnd(this string text, string value, StringComparison comparison)
+		=> text.EndsWith(value, comparison)
+			? text.Substring(0, text.Length - value.Length)
+			: text;
 }

src/Uno.Extensions.Reactive.Generator/Bindables/BindableViewModelGenerator.cs

@@ -79,9 +79,12 @@ private static string GetViewModelName(INamedTypeSymbol type)
 		var isLegacyMode = type.ContainingAssembly.FindAttribute<ImplicitBindablesAttribute>() is { Patterns.Length: 1 } config
 			&& config.Patterns[0] is ImplicitBindablesAttribute.LegacyPattern;
 
-		return !isLegacyMode && type.Name.IndexOf("ViewModel", StringComparison.OrdinalIgnoreCase) < 0
-			? $"{type.Name}ViewModel"
-			: $"Bindable{type.Name}";
+		return isLegacyMode switch
+		{
+			true => $"Bindable{type.Name}",
+			_ when type.Name.EndsWith("ViewModel", StringComparison.OrdinalIgnoreCase) => $"Bindable{type.Name}",
+			_ => $"{type.Name.TrimEnd("Model", StringComparison.OrdinalIgnoreCase)}ViewModel",
+		};
 	}
 
 	private string Generate(INamedTypeSymbol model)

src/Uno.Extensions.Reactive.Tests/Generator/Given_ViewModel_Then_GenerateBindable.cs

@@ -96,7 +96,12 @@ public void NestedInheritingViewModel()
 		=> Assert.IsNotNull(GetBindable(typeof(NestedSubViewModel)));
 
 	private Type? GetBindable(Type vmType)
-		=> vmType.GetNestedType(vmType.Name.Contains("ViewModel") ? $"Bindable{vmType.Name}" : $"{vmType.Name}ViewModel");
+		=> vmType.GetNestedType(vmType.Name switch
+		{
+			{ } name when name.EndsWith("ViewModel", StringComparison.OrdinalIgnoreCase) => $"Bindable{vmType.Name}",
+			{ } name when name.EndsWith("Model", StringComparison.OrdinalIgnoreCase) => $"{name.Substring(0, name.Length - "Model".Length)}ViewModel",
+			{ } name => $"{name}ViewModel",
+		});
 
 	private Type? GetBindable(string vmType)
 	{