Editing Null pointer (section)

== Other languages ==

In some programming language environments (at least one proprietary Lisp implementation, for example),{{citation needed|date=September 2011}} the value used as the null pointer (called <code>nil</code> in [[Lisp (programming language)|Lisp]]) may actually be a pointer to a block of internal data useful to the implementation (but not explicitly reachable from user programs), thus allowing the same register to be used as a useful constant and a quick way of accessing implementation internals.  This is known as the <code>nil</code> vector.

In languages with a [[tagged architecture]], a possibly null pointer can be replaced with a [[tagged union]] which enforces explicit handling of the exceptional case; in fact, a possibly null pointer can be seen as a [[tagged pointer]] with a computed tag.

Programming languages use different literals for the ''null pointer''. In [[Python (programming language)|Python]], for example, a null value is called <code>None</code>. In [[Java (programming language)|Java]] and [[C Sharp (programming language)|C#]], the literal <code>null</code> is provided as a literal for reference types. In [[Pascal (programming language)|Pascal]] and [[Swift (programming language)|Swift]], a null pointer is called <code>nil</code>. In [[Eiffel (programming language)|Eiffel]], it is called a <code>void</code> reference.