Changing Immutable Objects

Changing immutable objects

We do sometimes need to “change” immutable objects. Of course, you can’t actually do that, but what you can do is create a copy of the original object, modified in some way. There are various ways of doing this, which we will explore here.

Let’s start with a simple example. The tail function takes a list and returns a list that is identical except that the first term is removed. So, [1, 2, 3] becomes [2, 3]. Here is how we might do this: