Re:Lisp and Haskell (2015)
by boloust on Thursday October 08, 2020 @07:06AM
(#24717953)
The issue with null, as commonly implemented, is that null is a value that inhabits all types. So in that sense it is a defect of the type system.
[ Parent
| on HN ]
In Common Lisp, T is the "any" type (which makes sense there, as type specifiers can be formed using unions using (or type-A type-B ...) lists), the value NIL is the sole instance of the type NULL.