Exotic Programming Ideas, Part 3: Effect Systems(stephendiehl.com)

   - Oleg eats lambdas for breakfast

   - The Y combinator fears Oleg

   - Oleg knows all the programs that halt on a Turing machine

   - Oleg is the guy that Chuck Norris goes to when he has an algorithm complexity question

   - Oleg reprograms his own DNA with Scheme macros

   - All of Oleg's Haskell programs are well-typed by definition

   - Oleg can read C++ compiler error messages.

   - Oleg built his house out of Prolog relations

   - Oleg speaks machine lanugage

   - Oleg once turned a zero into a one.

   - Emacs? Vi? Oleg wills files into existance

   - Oleg has the Haskell98 Report memorized. In Binary. In UTF-EBCDIC

   - Oleg can write unhygienic syntax-rules macros.

   - Sometimes Recursion gets confused when Oleg uses it.

    handleReq req = 
      withTraceSpan (...)
      . withLogging (...)
      $ handleReqInner req

  (defvar x 0) ; x is global so dynamically scoped

  (defun f (g) (let ((x 1)) (funcall g))

  (let ((x 2))
    (f (lambda () (print x))))
  ; => 1
  (print x)
  ; => 0

  fun add-refs( a : ref<h,int>, b : ref<h,int> ) : st<h> int {
    a := 10
    b := 20
    (!a + !b)
  }

  fun sqr(x : int) : total int { x*x }

  [[int -> total int]]  = Z -> Z

  [[int -> exn int]] = Z -> (Z + 1)

  [[int -> st<h> int]] =  (H,Z) -> (H,Z)

  [[int -> div int]] = Z -> Z_\bot

    while true { }

    while i < 5 { i—-; }