[Haskell-beginners] questionnaire data design patterns

[Amy de Buitléir]

Hi Alia,

Here's my suggestion. It does compile.

Of course, there are lots of ways to approach this kind of thing. My choice was
to refactor it so that the Answer type contains the correct answer and the
possible answers, as appropriate. Then when you write the method that prompts
the user for an answer, and the method that checks the user's answer, you can
pattern match on the Answer type.

-----
module Main where

data Answer = Open
            | Test { correctIntAnswer :: Int }
            | Choice { correctStringAnswer :: Int, options :: [(String, String)] }
            deriving (Show, Eq)

data Question = Question
    { questionName  :: String
    , questionText  :: String
    , answer :: Answer
    } deriving (Show, Eq)

data QuestionSet = QuestionSet
    { qsetTitle     :: String
    , qsetQuestions :: [Question]
    } deriving (Show, Eq)

data Questionnaire = Questionnaire
    { questionnaireTitle        :: String
    , questionnaireQuestionSets :: [QuestionSet]
    } deriving (Show, Eq)

q1 = Question
    { questionName  = "q1"
    , questionText  = "What is our name?"
    , answer        = Open
    }

q2 = Question
    { questionName  = "q2"
    , questionText  = "What is 1+1?"
    , answer        = Test 2
    }

q3 = Question
    { questionName  = "q2"
    , questionText  = "What is 2+1?"
    , answer        = Choice 3 [("1", "2"), ("2", "3"), ("3", "4")]
    }

qset = QuestionSet
    { qsetTitle     = "simple questions"
    , qsetQuestions = [q1, q2, q3]
    }

questionnaire = Questionnaire
    { questionnaireTitle        = "a questionnaire"
    , questionnaireQuestionSets = [qset]
    }