Add gestureRecognizer shortland modifier

[edgarfgp]

Span("Hello")
    .font(size = 14.)
    .gestureRecognizer(TapGestureRecognizer(TapCommand))

[TimLariviere]

I would be very careful with this kind of shorthand.

Having 2 modifiers to do the same thing (gestureRecognizers vs gestureRecognizer) could lead to unwanted behavior and crashes, because Fabulous will treat those 2 modifiers as independants even though they both work with the same collection behind the scene.

So doing this would be possible:

Label("Hello")
    .gestureRecognizer(TapGestureRecognizer(Tapped))
    .gestureRecognizers() {
        DragGestureRecognizer(Dragged)
    }

As a user, I would expect both gestures to be applied, but most likely Fabulous will just crash because it expects 1 property = 1 modifier exclusively to be able to do diffing correctly.

In this case, when applying Tapped, Fabulous expects the Gestures collection to be empty but it already contains Dragged. Most likely, this will result in a IndexOutOfRange at some point.

[TimLariviere]

If you really wish to have this kind of shorthand modifier, you need to keep a single AttributeDefinition for all variants of the same modifier. Like this Fabulous will know it's actually the same modifier and will work with only the "latest" one declared.

eg.

type ViewModifiers =
    // The main one that every other variants will call instead of creating their own attributes
    static member gestureRecognizers(this: WidgetBuilder<#IFabView>) =
        AttributeCollectionBuilder(...)

type ViewExtraModifiers =
    // The shorthand
    static member gestureRecognizer(this: WidgetBuilder<#IFabView>, gesture: WidgetBuilder<#IFabGestureRecognizer>) =
        this.gestureRecognizers() { gesture }

// Dragged is the latest one, Fabulous will ignore Tapped
Label("Hello")
    .gestureRecognizer(TapGestureRecognizer(Tapped))
    .gestureRecognizers() {
        DragGestureRecognizer(Dragged)
    }

// Tapped is the latest one, Fabulous will ignore Dragged
(Label("Hello")
    .gestureRecognizers() {
        DragGestureRecognizer(Dragged)
    })
    .gestureRecognizer(TapGestureRecognizer(Tapped))

[edgarfgp]

@TimLariviere This is ready