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?

>>38
But types can be and are meaningful for execution. Just as types are a good thing for compilers to understand, it is equally a good thing for your programs to understand types in a symmetric way while it executes, and perform computations based on this type information. Run-time objects having types is a very useful and important concept.

The choice of value types represented at compile-time by a tagged union does not encompass all the possible types of the Haskell language, and any function compiled to manually dispatch over the tags of a tagged union at run-time must be recompiled if a new type is added (something very undesirable)

Using your terminology, Common Lisp reifies types in machine language (Lisp values (or run-time objects whatever) have and carry type information which Lisp programs compiled by the same compiler recognize in a uniform way).