I'm the author of a .NET RethinkDB client (https://github.com/mfenniak/rethinkdb-net https://github.com/mfenniak/rethinkdb-net), and I can add that RethinkDB's

I'm the author of a .NET RethinkDB client (https://github.com/mfenniak/rethinkdb-net https://github.com/mfenniak/rethinkdb-net), and I can add that RethinkDB's lambda functions were very easy to implement in .NET by using C#'s expression tree feature (http://msdn.microsoft.com/en-us/library/bb397951.aspx http://msdn.microsoft.com/en-us/library/bb397951.aspx). With that feature, a lambda can automatically be converted to an AST by creating a function that takes an Expression<Func<...>> parameter, which can easily be traversed and converted into RethinkDB's expression tree. Expression trees were introduced at the same time as LINQ, to support LINQ.