We have seen many examples of Scala's list. Lists are sequences. Moreover, lists are strict sequences. Meaning all elements of the list are constructed upfront. However, there are non-strict sequences, whose elements are constructed as needed.
A list is formed by connecting cons cells. There are two cases:
1 :: Nil
In this case, the cons cell has a value and the empty list as a tail. This list has only one element. Let's fire up the REPL and try the following snippets:
scala> 1 :: Nil res2: List[Int] = List(1)
1 :: 2 :: Nil
Here, we have the cons cell having a value and another list as a tail:
scala> (1 :: (2 :: Nil)).tail res11: List[Int] = List(2)
A list with three elements looks like the following:
scala> val ...