Unityped vs multityped

Performance Warning: Matrix values are arrays, as exported by math/array. The same performance warning applies: operations are currently 25-50 times slower in untyped Racket than in Typed Racket, due to the overhead of checking higher-order contracts. We are working on it.
http://docs.racket-lang.org/math/matrices.html

Still not convinced that unityped languages suck ass?

>>37
There is no such thing as "run-time typing". There are runtime classification tags and Haskell has them just like Lisp. For example, for values of the type Either a b you can test at runtime whether they're Left a or Right b, but all of them will have type Either a b and the compiler will be able to use that information.
Types only exist as lexical program text entities understood by the compiler, not the program you write!
Precisely. That's the way it is in both Lisp and Haskell. .NET goes a bit further by reifying types in bytecode, so they are not text entities - but still program entities to let the compiler instantiate generic classes and functions into native code. But that doesn't change the fact you're correct - types are only meaningful for the compiler, not for execution!