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S-expression

In computer programming, an S-expression (or symbolic expression, abbreviated as sexpr or sexp) is an expression in a like-named notation for nested list (tree-structured) data. S-expressions were invented for, and popularized by, the programming language Lisp, which uses them for source code as well as data.

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Characteristics

SyntaxExpressionOrdered pairListRecursive
29 related topics

Standardization

R6RSISLISPRon RivestInternet DraftRFC
15 related topics

Uses

Polish notationBooleanCons cellsM-expressionsHomoiconic
8 related topics

Relation to XML

CDATAXPath
2 related topics

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Overview

Characteristics

Uses

Relation to XML

Standardization

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Map overview Semantic statistics

S-expression

Nodes65
Edges64
Triples64
Avg. degree1.97
Density0.030769
Components1

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S-expression

Top relations

related to Standardization · 21
S-expression → ANSI, ANSI INCITS, Common Lisp, In May, Internet Draft, ISLISP, It, Lisp S-expressions, Lisp-derived, R2004, R5RS, R6RS, RFC, RFCs, Ron Rivest, Scheme, SPKI, Standards, The, These
related to Use in Lisp · 10
S-expression → As, Boolean, In, Lisp, Lisp's, LISP-like, Polish, This, Unicode, When
related to Datatypes and syntax · 7
S-expression → Hello, Integers, Lists, Strings, Symbols, The, There
related to Relation to XML · 6
S-expression → Another, CDATA, For, S-expressions, XML, XPath
related to External links · 5
S-expression → C/C, GitHubminilisp, Léon Bottou, Rosettacode, S-expressions
related to Characteristics · 3
S-expression → In, Lisp, S-expressions
related to Other uses · 2
S-expression → S-expressions, WebAssembly

Important terminology Word statistics

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Important terminology

s-expressions lisp data notation syntax representation xml code used programming use expression list strings languages prefix using also uses definition

Entity relationships Subject–Predicate–Object triples

SubjectPredicateObjectConfidenceSrc
Common Lispinstance ofModern Lisp dialects0.80text
Scheme provide such syntax via datum labelsinstance ofModern Lisp dialects0.80text
with which objects can be markedinstance ofModern Lisp dialects0.80text
which can then recur elsewhereinstance ofModern Lisp dialects0.80text
indicating shared rather than duplicated structureinstance ofModern Lisp dialects0.80text
enabling the reader or printer to detectinstance ofModern Lisp dialects0.80text
thus trigger evaluation or display of cycles without infinitely recursinginstance ofModern Lisp dialects0.80text
DSSSLinstance ofOther uses of S-expressions are in Lisp-derived languages0.80text
and as mark-up in communication protocols like IMAPinstance ofOther uses of S-expressions are in Lisp-derived languages0.80text
John McCarthy's CBCLinstance ofOther uses of S-expressions are in Lisp-derived languages0.80text
S-expressionrelated to CharacteristicsIn0.60section
S-expressionrelated to CharacteristicsLisp0.60section

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