AXSG compiles Avalonia XAML into generated C# and then layers runtime, language-service, and editor tooling on top of that compiler. The goal is to keep XAML authoring productive without treating XAML as a reflection-only runtime artifact.
What AXSG changes
Compared with a plain XAML pipeline, AXSG emphasizes:
generated C# output you can inspect, diff, debug, and reason about
stronger semantic checking for bindings, selectors, themes, includes, and resource references
C# expression features that still stay inside valid XAML forms
runtime support for hot reload, hot design, and generated fallback services
editor features that understand compiler semantics instead of only XML structure
Where it fits
AXSG is useful when you need one or more of these:
compile-time validation for XAML-heavy UI codebases
generated code you can audit or profile
richer binding/expression syntax without code-behind event handlers
editor tooling that follows the same semantics as the build
runtime support for hot reload and design-time workflows
Main feature families
XAML language features
compiled bindings with explicit and inferred source context
shorthand expressions and full expression bindings
inline C# in attribute, object-element, and CDATA forms
event bindings and inline event code
selector, control-theme, resource, include, and URI navigation support
Runtime features
generated helper/runtime contracts
hot reload registration and replacement logic
hot design and registry-backed tooling surfaces
runtime fallback services where generated code delegates execution