initials firstname lastname = [f] ++ ". " ++ [l] ++ "."
    where (f:_) = firstname
          (l:_) = lastname
-- Alternative: initials (f:_) (l:_) = [f] ++ ". " ++ [l] ++ "."
-- initials "Felipo" "Soranz"

calcBmis :: (RealFloat a) => [(a, a)]
initials :: String -> String -> String
initials firstname lastname = [f] ++ ". " ++ [l] ++ "."
    where (f:_) = firstname
          (l:_) = lastname
-- Alternative: initials (f:_) (l:_) = [f] ++ ". " ++ [l] ++ "."
-- initials "Felipo" "Soranz"
initials firstname lastname = [f] ++ ". " ++ [l] ++ "."
    where (f:_) = firstname
          (l:_) = lastname
-- Alternative: initials (f:_) (l:_) = [f] ++ ". " ++ [l] ++ "."
-- initials "Felipo" "Soranz"