lambda linguistic and logical interface

For a long time I've been amazed how much the `lambda` expression construct gives you. The introduction of name into expressions is seen through `let` which is syntactic sugar for lambda underneath. I believe Scala `for` nested iterations are also syntactic sugar toward flatmap + lambda. It's also a clean expression of data dependency. The sub-expression has meaning only if the lambda abstraction can be reduced by application to values. Otherwise well it's another smaller lambda expression. Wonderful.