Symbolic Expression
manual
manual reference zettelstore
zmk
00001012000000 00001012920516 00001012920525 00001012921000 00001012931000
00001012000000 00001012920516 00001012920525 00001012921000 00001012931000
1
(c) 2020-present by Detlef Stern <ds@zettelstore.de>
20230403145644
00001012930500
en
EUPL-1.2-or-later
20230403154010
20230403154010
public
A symbolic expression (also called s-expression) is a notation of a list-based tree. Inner nodes are lists of arbitrary length, outer nodes are primitive values (also called atoms) or the empty list.
A symbolic expression is either
a primitive value (atom), or
a list of the form (E1 E2 … En), where Ei is itself a symbolic expression, separated by space characters.
An atom is a number, a string, or a symbol.
Symbolic expressions are used in programming languages like LISP or Scheme, where they denote both data structures and the program itself. This allows a LISP or Scheme program to process LISP or Scheme programs. That property is also used within Zettelstore.
Symbolic expressions are relatively easy to read, to parse, and to process.
See also
Syntax of symbolic expressions in the Zettelstore
S-expression @ Wikipedia