C# library for error handling in a functional style (inspired by Scala and Haskell) - Option (Maybe), Try. This helps preserve referential transparency when working with operations that might fail (result is unavailable, or they throw an exception). Results of these operations can be seamlessly used in LINQ queries (see examples).
This implementation was inspired by the Scala and Haskell languages and by an article about Maybe monad http://lanshiva.blogspot.co.at/2011/02/applied-functional-programming-in-c.html
Option - Basically a Maybe monad, i.e. a container for a value or nothing. Basic idea is very similar to Nullable, but is applicable to classes as well. It provides numerous advantages over the basic Nullable wrapper.