Haskell-book/11/Programmer.hs


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module Programmer where

data OperatingSystem = GnuPlusLinux
                     | OpenBSDPlusNevermindJustBSDStill
                     | Mac
                     | Windows
                     deriving (Eq, Show)

data ProgLang = Haskell
              | Agda
              | Idris
              | PureScript
              deriving (Eq, Show)

data Programmer = Programmer { os :: OperatingSystem
                             , lang :: ProgLang }
                  deriving (Eq, Show)

allOperatingSystems :: [OperatingSystem]
allOperatingSystems =
    [ GnuPlusLinux
    , OpenBSDPlusNevermindJustBSDStill
    , Mac
    , Windows
    ]

allLanguages :: [ProgLang]
allLanguages =
    [ Haskell
    , Agda
    , Idris
    , PureScript
    ]

allProgrammers :: [Programmer]
allProgrammers = do
    o <- allOperatingSystems
    l <- allLanguages
    return Programmer { os = o
                      , lang = l }