# s-expression

tags
: [[programming]] [[programming languages]]

An s-expression is a notation for listed data, often used by [[Lisp]] programming languages, where they represent both the program and the data.

Initially s-expressions were just cons cells ([[linked lists]]), so they could be represented as:

```text
(1 . (2 . (3 . NIL)))
```

However modern Lisps either do not use linked lists or do not make this clear to the programmer.