where.hs

bmiTell :: (RealFloat a) => a -> a -> String  
bmiTell weight height  
    | weight / height ^ 2 <= 18.5 = "You're underweight, you emo, you!"  
    | weight / height ^ 2 <= 25.0 = "You're supposedly normal. Pffft, I bet you're ugly!"  
    | weight / height ^ 2 <= 30.0 = "You're fat! Lose some weight, fatty!"  
    | otherwise                   = "You're a whale, congratulations!"  

-- DRY

bmiTell' :: (RealFloat a) => a -> a -> String  
bmiTell' weight height  
    | bmi <= 18.5 = "You're underweight, you emo, you!"
    | bmi <= 25.0 = "You're supposedly normal. Pffft, I bet you're ugly!"  
    | bmi <= 30.0 = "You're fat! Lose some weight, fatty!"  
    | otherwise   = "You're a whale, congratulations!"  
    where bmi = weight / height ^ 2  

bmiCalc weight height = weight / height ^ 2 

--         Kg Meters
-- bmiCalc 60 1.68

bmiTell'' :: (RealFloat a) => a -> a -> String  
bmiTell'' weight height  
    | bmi <= skinny = "You're underweight, you emo, you!"
    | bmi <= normal = "You're supposedly normal. Pffft, I bet you're ugly!"  
    | bmi <= fat = "You're fat! Lose some weight, fatty!"  
    | otherwise   = "You're a whale, congratulations!"  
    where bmi = weight / height ^ 2 
          skinny = 18.5  
          normal = 25.0  
          fat = 30.0  

initials :: String -> String -> String  
initials firstname lastname = [f] ++ ". " ++ [l] ++ "."  
    where (f:_) = firstname  
          (l:_) = lastname   

initials' :: String -> String -> String  
initials' (f:_) (l:_) = [f] ++ ". " ++ [l] ++ "."  

calcBmis :: (RealFloat a) => [(a, a)] -> [a]  
calcBmis xs = [bmi w h | (w, h) <- xs]  
    where bmi weight height = weight / height ^ 2  

-- helper functions