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182:. An SGML document is a text document with SGML markup defined in an SGML prologue (i.e., the DTD and subdocuments). A complete SGML document comprises not only the document instance itself, but also the prologue and, optionally, the SGML declaration (which defines the document's markup syntax and declares the
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entity contains any kind of data, and a reference to it will result in the application's merely being notified of the entity's presence; the content of the entity will not be parsed, even if it is text. An unparsed entity can only be
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devices, to ease document authoring when there is a need to use characters that are not easily typed or that are not widely supported by legacy character encodings. Each such entity consists of just one character from the
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Additional markup constructs and processor options may affect whether and how entities are processed. For example, a processor may optionally ignore external entities.
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entity contains text, which will be incorporated into the document and parsed if the entity is referenced. A parameter entity can only be a parsed entity.
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When parsed, this document would be reported to the downstream application the same as if it has been written as follows, assuming the
43:). Entities are foundational to the organizational structure and definition of SGML documents. The SGML specification defines numerous
51:, SGML tags, and/or references to previously defined entities. Certain entity types may also invoke external documents. Entities are
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A reference to an undeclared entity is an error unless a default entity has been defined. For example:
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When an external entity references a complete SGML document, it is known in the calling document as an
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string, or a parsed string comprising markup and entities defined in the same document (such as a
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An entity declaration may have a literal value, or may have some combination of an optional
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The general entities from the example above might be referenced in a document as follows:
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identifier, which identifies the entity independent of any particular representation. In
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has 252 built-in character entities that do not need to be explicitly declared, while
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Standard entity sets for SGML and some of its derivatives have been developed as
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has the same five as XML, but if its DTDs are explicitly used, then it has 253 (
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that invokes an external document, thereby necessitating the intervention of an
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396:. Parsed general entities are referenced by placing the entity name between "
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exists and consists of the text found in the resource identified by the
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with either a unique alias (such as a user-specified name) or an SGML
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Parameter entities are referenced by placing the entity name between
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Entities are also further classified as parsed or unparsed:
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entity can only be referenced within the document content.
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allows characters to be referenced by name instead of
601:. Although any character can be referenced using a
63:Entities are classified as general or parameter:
652:List of XML and HTML character entity references
632:being the extra entity beyond those in HTML 4).
708:Goldfarb, Charles F., and Yuri Rubinsky (Ed.).
677:"Web SGML and HTML 4.0 Explained - Chapter 6"
381:Names for entities must follow the rules for
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135:to resolve the external document reference.
554:. Unsourced material may be challenged and
228:. Unsourced material may be challenged and
574:Learn how and when to remove this message
248:Learn how and when to remove this message
78:entity can only be referenced within the
469:'Helloworld'isacommonteststring.
329:This DTD markup declares the following:
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162:, an entity declaration may not have a
504:"This entity is not defined"
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552:adding citations to reliable sources
321:"%greeting3; means Hello!"
226:adding citations to reliable sources
18:Standard Generalized Markup Language
476:Thecontentofhello.txtis:Salutations
358:An internal parameter entity named
373:exists and consists of the string
362:exists and consists of the string
337:exists and consists of the string
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369:An internal general entity named
344:An external general entity named
333:An internal general entity named
123:or subdocument). In contrast, an
712:. Oxford University Press, 1991.
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107:Internal and external entities
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294:"file:///hello.txt"
115:has a value that is either a
701:Goldfarb, Charles F. (Ed.).
260:An entity is defined via an
603:numeric character reference
483:InSpanish,¡Hola!meansHello!
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703:ISO 8879 Review: WG8 N1855
657:XML external entity attack
607:character entity reference
588:Character entity reference
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723:Entity Management in SGML
705:. WG8 and Liaisons, 1996.
647:Object (computer science)
421:'isacommonteststring.
121:Document Type Declaration
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428:Thecontentofhello.txtis:
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266:document type definition
80:document type definition
642:Declarative programming
599:Universal Character Set
455:file contains the text
279:"Hello world"
166:identifier without a
31:, which associates a
681:www.is-thought.co.uk
548:improve this section
268:(DTD). For example:
222:improve this section
180:SGML document entity
174:SGML document entity
375:¡Hola! means Hello!
53:called by reference
516:Character entities
309:"¡Hola!"
262:entity declaration
184:character encoding
710:The SGML Handbook
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59:Entity types
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498:<!ENTITY
457:Salutations
339:Hello world
315:<!ENTITY
300:<!ENTITY
285:<!ENTITY
273:<!ENTITY
129:declaration
20:(SGML), an
732:Categories
696:References
630:'
624:has five.
611:code point
564:April 2009
438:InSpanish,
383:SGML names
238:April 2009
148:identifier
49:plain text
535:does not
453:hello.txt
371:greeting4
360:greeting3
346:greeting2
335:greeting1
318:greeting4
306:greeting3
288:greeting2
276:greeting1
209:does not
102:external.
76:parameter
39:(such as
29:data type
26:primitive
636:See also
594:mnemonic
501:#DEFAULT
99:unparsed
41:#DEFAULT
556:removed
541:sources
400:" and "
230:removed
215:sources
117:literal
69:general
16:In the
618:HTML 4
364:¡Hola!
291:SYSTEM
190:Syntax
168:SYSTEM
164:PUBLIC
152:PUBLIC
145:SYSTEM
127:has a
92:parsed
82:(DTD).
33:string
22:entity
663:Notes
626:XHTML
417:'
398:&
24:is a
743:SGML
605:, a
539:any
537:cite
507:>
392:and
324:>
312:>
297:>
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213:any
211:cite
160:SGML
622:XML
550:by
350:URI
224:by
186:).
156:XML
111:An
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