XAML has been discussed a bunch lately. It is easiest to show people what it is in person, but since that won't scale, I'll try to convey the same points by posting markup samples, descriptions and screenshots.
Avalon, Longhorn & XAML
Avalon is a presentation platform for the next generation of Windows (“Longhorn“). XAML is a markup language that can be used on Longhorn for many things including creating desktop apps, web pages, and printable documents. The system is very extensible. If you want to build your own set of elements, you have the power to do that. If you want to mix those elements with ours, you can. If you want to just use yours, you can. If you don't like angle brackets and would like to use only code, you can do that as well.
That being said, let's talk about the 5 element families that Avalon has in the build we just released at the PDC: Panels, Controls, Shapes, Decorators and ContentElements.
Elements which Measure, Arrange and Render their children in the element tree (DockPanel, FlowPanel, TextPanel, etc…)
Elements which provide keyboard and mouse interaction models for the user (Button, TextBox, etc…)
Elements which will render vector shapes (Ellipse, Rectangle, Path, etc…)
Elements that can contain 1 child, and will adorn or affect the rendering of that child. (Border, TransformDecorator)
ContentElements* (needs renaming)
Elements which provide semantic meaning for a documents structure (Paragraph, Section, Heading, etc…) and a few formatting tags (Bold, etc…)
Using elements from those 5 families, we are trying to enable developers & designers the power to build great user experiences for Windows “Longhorn“. We also want to provide a consistent markup and programming model experience in all of these element families.
In future posts, I'll drill down in each of these families, showing some markup and code examples and pointing you towards more information from our SDK and blogs.