content: --------------------------------------------------------------------------------
  -- MIT License
  --
  -- Copyright (C) 2023 Duck McSouls <quacksouls [AT] gmail [DOT] com>
  --
  -- Permission is hereby granted, free of charge, to any person obtaining a copy
  -- of this software and associated documentation files (the "Software"), to deal
  -- in the Software without restriction, including without limitation the rights
  -- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  -- copies of the Software, and to permit persons to whom the Software is
  -- furnished to do so, subject to the following conditions:
  --
  -- The above copyright notice and this permission notice shall be included in
  -- all copies or substantial portions of the Software.
  --
  -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  -- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  -- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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  --------------------------------------------------------------------------------
  
  import Text.Printf
  
  -- | The maximum of three integers.
  max3 :: Integer -> Integer -> Integer -> Integer
  max3 a b c
      | a >= b && a >= c = a
      | b >= a && b >= c = b
      | otherwise = c
  
  -- | Determine the greatest of three integers.
  main = do
      let a = 1 :: Integer
      let b = 2 :: Integer
      let c = 3 :: Integer
      let test1 = (max a $ max b c) == max3 a b c
      let test2 = (max (-a) $ max b c) == max3 (-a) b c
      let test3 = (max a $ max (-b) c) == max3 a (-b) c
      let test4 = (max a $ max b (-c)) == max3 a b (-c)
      printf "%d, %d, %d: %d, %s\n" a b c (max3 a b c) $ show test1
      printf "%d, %d, %d: %d, %s\n" (-a) b c (max3 (-a) b c) $ show test2
      printf "%d, %d, %d: %d, %s\n" a (-b) c (max3 a (-b) c) $ show test3
      printf "%d, %d, %d: %d, %s\n" a b (-c) (max3 a b (-c)) $ show test4
  