A shopping cart DSL built on top of Roslyn APIs.
Down below you will find a couple of blog posts on how to use it, extend it, and include these kinds of DSLs in your LOB apps.
Thanks for stopping by and please free to contact me if you have any questions.
http://alemiralles.blogspot.com.ar/2012/11/roslyn-shopping-cart-part-1.html
http://alemiralles.blogspot.com.ar/2012/11/roslyn-shopping-cart-dsl-part-2.html
http://alemiralles.blogspot.com.ar/2012/12/roslyn-shopping-cart-dsl-part-3.html
http://alemiralles.blogspot.com.ar/2012/12/roslyn-shopping-cart-dsl-part-4.html