[racket] Defining a typed language

Matthias Felleisen writes:

 > Konrad, I am surprised you want to remove contracts from
 > Typed-Untyped boundaries given your history of praising types on
 > this mailing list. But yes, you're on the right track.

I don't want to remove contracts from the boundaries, I want to remove
the boundaries themselves, by making my modules typed but using my own
specialized language.

More concretely, I want to be able to use the Math library from my own
modules without incurring the cost of a contract at any element
access.

Overall I am quite happy with Typed Racket's type system, the only
serious problem I ever encountered being the cyclic data structures
discussed recently. And even for those, the solution Sam posted is
quite nice in practice, but not very obvious to find.

Konrad