XamlX - WinUI

This repo contains the source code for the 2020 Hackathon project to bring the XamlX compiler to WinUI3.

What is XamlX?

Taken from the XamlX (linked above) readme, XamlX is a:

General purpose pluggable XAML compiler with no runtime dependencies. Currently being used by Avalonia project as the XAML engine. The compiler isn't tied to Avalonia in any way, shape or form and can be used for any purposes by configuring XamlLanguageTypeMappings to match the needs of your particular framework. Further customization can be done by AST manipulations, see examples of those in Avaloni repository.

One of the key differences between XamlX and the way that WPF and WinUI have serialized XAML files, is that they generate Intermediate Language (IL) instructions, rather than a binary format reprenstation of the markup (BAML/XBF). This enables support for any .NET language, and doesn't require individual work for C#, VB, or F#.

Debugging Features of XamlX

XamlX has some really cool debugging features, the below images are curtosy of a tweet from Jumar Macato (Twitter: @jumarmacatoto)

Xaml Breakpoints!

Inline XamlParse Exceptions!

Getting Started

How to debug the current Avalonia Compiler:

Debug Unit tests in Avalonia.Markup.Xaml

Goals

Enable compilation of WinUI3 applications using a XamlX based compiler, similar to the Avalonia Compiler
Add support for emitting C++ backend
Ensure support for WinUI Specific language features:
- (P0) x:Bind
- (P0) x:Load
- (P1) x:Phase
Xaml Direct transforms and a special emitter for method calls?
Add support for new collection syntax being added:

<Grid ColumnDefinitions="*,*.Auto"/>

Project Plan

Parallelizable work:

C++/WinRT backend
Adding support for WinUI
xaml direct transforms
standalone exe

Standalone exe

Make a standalone exe for easy testing and inner loop.

C++ Backend

Emitters all the basic logic for the nodes
Follow pattern for IL folder here: https://github.com/kekekeks/XamlX/tree/master/src/XamlX
Can use Cecil which has support .winmd for local types
- Property on CecilReader called ApplyWindowsRuntimeProjections - set this to false.

Emitters are templated on two types:

Result Type - valid vs invalid. Emitter returns invalid result if it doesn't emit anything. Chain of responsiblity, so if one emitter can't do it, moves on to the next one.
Base emitter - as close to the primitive instructions as needed.

Node Emitter's call methods on base emitter to emit the node. Base emitter is passed to the node.

Xaml Direct transform

Assigned to: Jeremy

WinUI Support

Copying Avalonia compiler
Adding WinUI specific language features

Limitiations and Workarounds

Parsing Windows.UI.Color

XamlX uses TypeConverters, or looks for a static Parse method to convert types from string. Since WinRT doesn't support type converters, and we can't have methods on structs, you can't do something like this: <SolidColorBrush x:Key="RedBrush" Color="Red"/>

Workaround is to use x:Static and do this instead:

<SolidColorBrush x:Key="RedBrush" Color="{x:Static Colors.Red}"/>

License

This project is licensed with the MIT license.

Related Projects

You should take a look at these related projects:

stevenbrix/xamlx-winui