haskell：谁能解释以下代数数据类型

Question

could anyone explain the below algebric data type

data LOS = Cons Student LOS | Empty deriving (Show) 

and

type Name = String



data Student = Student           
  { firstName :: Name
  , lastName :: Name
  } deriving (Eq, Show)

I find it confusing the construction of the LOS data type

Answer 1

LOS is defining a list of students. You either have an empty list ( Empty ) or Cons , which holds both a value or the rest of the list.

You can have a list with an element ( Cons s1 Empty ), a list with two elements ( Cons s1 (Cons s2 Empty) ) and so on.