[epidemian]

The author is not complying with their own requirements:

> Pattern matching and polymorphism is not allowed

Using dynamic dispatch on different functions of type Int -> Int is, precisely, polymorphism. Doesn't look much like the OO polymorphism that some people are used to, but FP folks use this kind of functional polymorphism all the time.

That being said, the main premise of the article is quite valuable: yes, you can program with no conditionals. And i think it's quite useful to know that polymorphism can be used like that without suffering too much of an unfriendly syntax (see lmm's comment on Smalltalk: http://news.ycombinator.com/item?id=5198419).

Finally, although pattern matching can be seen as an overpowered if-statement, the relation can be also turned around: the if-statement is a special case of pattern matching. I won't say that pattern matching is not conditional statements, but i think it's also quite valuable to notice that you can use pattern matching as a new programming primitive instead of the if-statement. For example, the if-statement implemented in Haskell:

  if :: Bool -> a -> a -> a
  if True  x _ = x
  if False _ y = y

Relying only on pattern matching instead of conditional if-statements can make quite the difference on how one reasons about programming problems (e.g. Prolog and declarative programming in general).