NorfairKing

02/12 15:38:50: Launching app
$ adb shell am start -n "eu.cs_syd.intray/eu.cs_syd.intray.android.ui.activity.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Client not ready yet..Waiting for process to come online
Connected to process 18258 on device ulefone-power_3s-0123456789ABCDEF
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
W/System: ClassLoader referenced unknown path: /data/app/eu.cs_syd.intray-1/lib/arm64
I/art: Starting a blocking GC HeapTrim
I/InstantRun: starting instant run server: is main process
W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
V/PhoneWindow: D

NorfairKing

resolver: lts-11.13
packages:
- .

# https://github.com/NorfairKing/validity/tree/development
extra-deps:

  - git: [email protected]:NorfairKing/validity.git
    commit: 4de0a0eff895ee2dc7f0bc17cf65d3acb0a0cd5a
    subdirs:

NorfairKing

I've been thinking about where one would get started to find problems in code.

Ideally I'd come up with some mathematical properties to spot that would be
likely to indicate that bugs are more common.

Part 1: Possible implementations

One idea I've had stems from algebra. It starts with the concept of cardinality.
Out of all possible implementations of a solution to a certain problem, there
are only few of them that correctly solve the problem.

NorfairKing

newtype Deprecated a b = Deprecated { undeprecate :: a -> b }


(💩 ) :: Deprecated a b -> a -> b
(💩 ) = undeprecate

myDeprecatedFunction :: Deprecated Int Int
myDeprecatedFunction = Deprecated myFunction
  where
    myFunction :: Int -> Int

NorfairKing

module Problem where

bigBadMathProblem :: Integer -> Integer
bigBadMathProblem = (* 5)

NorfairKing

module TH where

import           Language.Haskell.TH

precompute :: [Int] -> DecsQ
precompute xs = do
  let name = mkName "lookupTable"
      patterns = map intToPat xs
      fnBodies = map precomputeInteger xs
      precomputedClauses =