https://news.ycombinator.com/item?id=25228079

add this to the list of pain points that would disappear if we got rid of improper lists..

I think I would miss 1.

btw, I think Sam’s definition of “An improper list is one whose final cons cell doesn’t have null in the cdr” is not right in the same way that “A proper list is one whose final cons cell does have null in the cdr” is not a correct definition of (proper) lists.

A proper list is either null or a pair of anything and a proper list.

An improper list is either a value that is not null or a pair, or a pair of anything and an improper list.

1 is neither null or a pair, so it is an improper list.