Supporting fixed-point expressions

FYI.

ATS also support the use of a fixed-point expression for defining an
anonymous function.
Here is an example:

val fib10 =
(fix f(x: int): int => if x >= 2 then f(x-1)+f(x-2) else x)(10)
val () = println! ("fib(10) = ", fib10)

For more examples of this kind, please see:

Cheers!