I have started a blog to talk about SW verification. In this blog I
use a variant of Eiffel called "Modern Eiffel". The latest blog entry
at
http://softwareverificaton.wordpress.com/2012/01/25/language-outline-7/
gives an outline of the language. It describes the use of inductive
data types (or sometimes called algebraic data types) within Modern
Eiffel.