On 05/04/2012, Grigory Sarnitskiy
One could expect from a language that bears 'functional' as its characteristic to be able to do everything imaginable with functions. However, the only thing Haskell can do with functions is to apply them to arguments and to feed them as arguments, run in parallel (run and concatenate programs).
Obviously, that's not all of the imaginable possibilities. One also can rewrite programs. And write programs that rewrite programs. And write programs that rewrite programs that rewrite the first programs and so on. But there is no such possibility in Haskell, except for introducing a DSL.
Note, that the reflectivity is important.
For x86 machine: http://hackage.haskell.org/package/hdis86 Truly, I often wish to be able to pattern match on functions myself. Alas, the function is not an algebraic data type.