Haskell/Solutions/Control structures

case expressions Use a case statement to implement a fakeIf function which might be used as a replacement to the familiar if expressions. fakeIf :: Bool -> a -> a -> a fakeIf condition ifTrue ifFalse = case condition of True -> ifTrue False -> ifFalse Controlling actions, revisited Redo the "Haskell greeting" exercise in Simple input and output/Controlling actions, this time using a case statement. What does the following program print out? And why? main = do x <- getX putStrLn x getX = do return "My Shangri-La" return "beneath" return "the summer moon" return "I will" return "return" return "again" 1. main = do putStrLn "Hello, what is your name?" name <- getLine case name of "Simon" -> greatlanguage "John" -> greatlanguage "Phil" -> greatlanguage "Koen" -> putStrLn "I think debugging Haskell is fun." _ -> putStrLn "Sorry, I don't know you." where greatlanguage = putStrLn "I think Haskell is a great programming language." 2. Executing main will print "again". Remember that the value of a sequence of IO actions is the same as the value of the last action in the sequence. getX can also be written as: getX = do return "again" or even shorter, as: getX = return "again" As a result, x in the main function has the value "again", which will then be written to the screen.