OperatorAssociativity.purs

module Main where

import Control.Monad.Eff
import Debug.Trace

foreign import data Assert :: !

foreign import assert
  "function assert(x) { return function (desc) {\
  \  return function () {\
  \    if (!x) throw new Error('assertion (' + desc + ') failed');\
  \    return {};\
  \  };\
  \};};" :: forall e. Boolean -> String -> Eff (assert :: Assert | e) Unit

bug :: Number -> Number -> Number
bug a b = 0 - (a - b)

foreign import explode
  "function explode() {\
  \  throw new Error('Assertion failed!');\
  \}":: forall eff a. Eff eff a

main = do
    assert (bug 0 2 == 2)       "bug 0 2 == 2"
    assert (0 - (0 - 2) == 2)   "0 - (0 - 2) == 2"
    assert (0 - (0 + 2) == -2)  "0 - (0 + 2) == -2"

    assert (6 / (3 * 2) == 1)   "6 / (3 * 2) == 1"
    assert ((6 / 3) * 2 == 4)   "(6 / 3) * 2 == 4"

    assert (6 % (2 * 2) == 2)   "6 % (2 * 2) == 2"
    assert ((6 % 2) * 2 == 0)   "(6 % 2) * 2 == 0"

    assert (4 % (9 / 3) == 1)   "4 % (9 / 3) == 1"
    assert ((4 % 9) / 2 == 2)   "(4 % 9) / 2 == 2"