| TITLE: | Recent Changes to ISO 8879 (C) Copyright 1998 International Organization for Standardization |
| SOURCE: | JTC1/WG4 |
| PROJECT: | JTC1.18.15.1 |
| PROJECT EDITOR: | Charles F. Goldfarb |
| STATUS: | Personal Contribution |
| ACTION: | For approval by WG4 |
| SUMMARY OF MAJOR POINTS: | This document collects in one place the changes made to ISO 8879 in 1997 (which are the only changes made since 1988). It incorporates corrections to Annexes K and L that are still undergoing formal approval. |
| DATE: | 18 March 1998 |
| DISTRIBUTION: | WG4 members and liaisons |
| REFER TO: | ISO 8879 |
| SUPERCEDES: | WG4 N1959, N1963 |
| REPLY TO: | Dr. James D. Mason
(ISO/IEC JTC1/WG4 Convenor) Lockheed Martin Energy Systems Information Technology Services 1060 Commerce Park Oak Ridge, TN 37830 U.S.A. Telephone: +1 423 574-6973 Facsimile: +1 423 574-6983 Network: masonjd@ornl.gov http://www.ornl.gov/sgml/wg4/ ftp://ftp.ornl.gov/pub/sgml/wg4/ |
All occurrences of "element declaration" in this International Standard are changed to "element type declaration".
All occurrences of "element set" in this International Standard are changed to "element type set".
Replace 4.223 with:
4.223 owner identifier: The portion of a public identifier that identifies its owner.Note: The owner of a public identifier is not necessarily the owner of the object that it identifies.
Add the following normative annexes J and K, and informative annex L, to ISO 8879.
This annex describes an optional extension of SGML known as the "Extended Naming Rules". The extension should be used only in SGML documents for which the normal naming rules are unsuitable (usually because of the size of the natural language character set). An SGML system need not support these Extended Naming Rules in order to be a conforming SGML system.
This annex is phrased in terms of revisions to be made to the body of this International Standard. However, these revisions are applicable only when the Extended Naming Rules are in use.
To distinguish SGML declarations that use this extension from those that do not, the minimum literal in productions [171] and [200] of ISO 8879:1986 must be modified to read "ISO 8879:1986 (ENR)". To accomplish this add the following sentence to the paragraph immediately following production [171] and to the second paragraph following production [200]:
However, when extended naming rules are used, the minimum data must be "ISO 8879:1986 (ENR)".
The extended naming rules are as follows.
For many languages the distinction made in production [189] between uppercase and lowercase is not relevant. It is, therefore, necessary to modify clause 13.4.5 to allow for both an extended character set and for the use of character sets that do not have different cases. The changes required, in the order of their occurrence in 13.4.5, are:
[189] naming rules =
"NAMING", ps+,
"LCNMSTRT", (ps+, extended naming value)+, ps+,
"UCNMSTRT", (ps+, extended naming value)+, ps+,
("NAMESTRT", (ps+, extended naming value)+, ps+)?,
"LCNMCHAR", (ps+, extended naming value)+, ps+,
"UCNMCHAR", (ps+, extended naming value)+, ps+,
("NAMECHAR", (ps+, extended naming value)+, ps+)?,
"NAMECASE", ps+,
"GENERAL", ps+, ("NO"| "YES"), ps+,
"ENTITY", ps+, ("NO"| "YES")
[189.1] extended naming value = parameter literal | character number | character range
A character number may be used to specify a character that is defined in the syntax-reference character set but is not permitted in an SGML declaration.
[189.2] character range = character number, ps*, minus, ps*, character number
Specifying a character range is equivalent to specifying every character number from (and including) the character number that starts the range to (and including) the character number that ends the range.
This annex remedies defects revealed by the multiple adaptations of SGML for the World Wide Web (WWW), intranets, and extranets. The annex corrects errors, resolves ambiguities for which there is a clear resolution that does not cause existing conforming documents to become non-conforming, and provides a choice of alternative resolutions for other ambiguities. Although motivated by the World Wide Web, applicability of this annex extends to all uses of SGML.
This annex makes reference to groves and property sets, which are defined in the SGML Extended Facilities of the 2nd Edition of HyTime (ISO/IEC 10744) and also in DSSSL (ISO/IEC 10179).
The decision to conform to this annex is made for individual documents and is indicated in the SGML declaration, as described below (K.3.2). An SGML system need not support this annex in order to be a conforming SGML system.
This annex is organized as a set of replacement and new syntax productions, and is phrased in terms of modifications to be made to the body of this International Standard, though the numbers of the affected clauses are not necessarily cited. However, these modifications are applicable only when conforming to this annex.
An SGML parser that supports this annex shall be able to parse conforming SGML documents that do not claim conformance to it. The parsing of such documents must produce the same grove as would a conforming SGML parser that does not support this annex. Error reporting for such documents, however, is with respect to the standard as modified by this annex; errors with respect to the unmodified standard need not be reported.
Markup declarations that occur in the external and internal subsets of document type declarations.
The portion of a document type declaration subset referenced by the external identifier parameter of a document type declaration.
The portion of a document type declaration subset that occurs between the dso and dsc of a document type declaration.
If the dso and dsc are omitted, the internal subset is empty (rather than non-existent).
A document instance in which a start-tag with a generic identifier, and an end-tag, are present for every element, and the attribute name is present in every attribute specification in the start-tag.
Note 1: An SGML declaration requires document instances to be fully-tagged if it specifies OMITTAG NO and SHORTTAG STARTTAG EMPTY NO and ATTRIB OMITNAME NO. A system should offer means, such as a parameter to the invocation of processing, to request validation of whether an instance is fully-tagged even when the SGML declaration does not require it to be.
A document instance for which, for every markup declaration required for it by the body of this International Standard, either:
The document type declaration itself could be an implied declaration, as provided in clause K.4.9.
Note 2: An SGML declaration requires document instances to be fully-declared if it specifies IMPLYDEF ATTLIST NO and ELEMENT NO ENTITY NO NOTATION NO. A system should offer means, such as a parameter to the invocation of processing, to request validation of whether an instance is fully-declared even when the SGML declaration does not require it to be.
A document instance that conforms to such markup declarations as are required for it by the body of this International Standard that are present in its associated document type declaration.
Note 3: An SGML system that supports unconstrained SGML documents must be able to parse DTD declarations and resolve both internal and external entity references. If it continues parsing (as a form of error-recovery) after failing to access a referenced entity, the results are unpredictable. Observing one or more of the entity constraints defined in this International Standard may cause a document to be more amenable to processing by a simpler SGML system, or in an environment (such as a network) where access to external entities may be slow or unreliable.
A document instance in which every element and marked section ends in the entity in which it begins.
Note 4: This constraint makes it possible, as a form of error-recovery, for parsing to continue in a fully-tagged document instance after a failure to access a referenced entity. The resulting grove will be the same for the parsed text, except for the tree addresses of younger siblings of the nodes in the inaccessible entity. The constraint also has implementation benefits for editors, "lazy" replacement of entity references, and sharing of grove portions when entities are reused.
An SGML document that has no entity references other than references to predefined data character entities.
Note 5: A reference-free document can be parsed by conforming SGML systems that cannot resolve entity references.
An SGML document that has no external entity references.
Note 6: An external-reference-free document could have attribute values that contain names of external entities or that otherwise might cause an application to access an external entity by means other than entity references.
Note 7: External-reference-free documents can be parsed by systems that cannot resolve external entity-references.
A general entity, associated with a character number in the syntax-reference character set, that is used to reference significant SGML characters as data.
Note 8: In order to allow delimiter escaping when parsing without respect to DTD declarations, there should be a predefined data character entity for the first character of each delimiter string that can be recognized in a mode where data can occur.
The characters assigned to the SEPCHAR, SPACE, RE, and RS functions.
[171] SGML declaration = "<!SGML", ps+, (SGML declaration body | SGML declaration reference), ps*, ">"
In order for SGML documents to be self-identifying, it is strongly recommended that all conforming SGML documents contain one of the forms of SGML declaration.
[171.2] SGML declaration reference = name, external identifier? where "name" is a name in the reference concrete syntax. "external identifier" must reference an SGML declaration body. If omitted, the external identifier is "SYSTEM".
A public identifier, if formal, shall use the public text class (10.2.2.1) "SD" to identify an SGML declaration body.
Note 9: For example:
<!SGML HTML3.2 PUBLIC "+//IDN W3C.ORG//SD HTML Version 3.2//EN">
[171.1] SGML declaration body = ps*, minimum literal, ps+, document character set, ps+, capacity set, ps+, concrete syntax scope, ps+, concrete syntax, ps+, feature use, ps+, application-specific information, (ps+, added requirements)?
The minimum data of the minimum literal shall be one of the following:
The ENR suffix indicates that the document conforms to Annex J of this International Standard.
The WWW suffix indicates that the document conforms to Annex K (this annex) of this International Standard, which incorporates by reference the provisions of Annex J of this International Standard and supersedes any contradictory provisions elsewhere in this International Standard.
Note 10: Certain parameters of the SGML declaration body are omissible in order to allow existing documents to conform to this annex by a simple change to the minimum data. Nevertheless, it is recommended that all parameters be specified.
[180] capacity set =
"CAPACITY", ps+,
(("PUBLIC", ps+, public identifier)|
"NONE"|
("SGMLREF", (ps+, name, ps+, number)*))
NONE indicates that no capacities are specified.
Specifying NONE does not require a system to support capacities greater than those specified in its system declaration.
[182] concrete syntax = "SYNTAX", ps+, (public concrete syntax | (shunned character number identification, ps+, syntax-reference character set, ps+, function character identification, ps+, naming rules, ps+, delimiter set, ps+, reserved name use, ps+, quantity set, (ps+, predefined data character entities)?))
[194] quantity set =
"QUANTITY", ps+,
("NONE"|
("SGMLREF", (ps+, name, ps+, number)*))
NONE indicates that no quantities are specified.
Specifying NONE does not require a system to support quantities greater than those specified in its system declaration.
[194.1] predefined data character entities =
"ENTITIES", ps+,
("NONE"|(parameter literal, ps+, character number)+)
Each interpreted "parameter literal" must be a valid general entity name in the syntax being defined, and is associated with a character number in the syntax-reference character set. When the named entity is referenced, the replacement text is a numeric character reference to the corresponding character. Predefined data character entities are treated as though defined at the start of the internal subset of all documents in which the concrete syntax is used.
Note 11: For example:
ENTITIES "amp" 38 "lt" 60 "gt" 62 "quot" 34 "apos" 39
[196] markup minimization features =
"MINIMIZE", ps+,
"DATATAG", ps+, ("NO"|"YES"), ps+,
"OMITTAG", ps+, ("NO"|"YES"), ps+,
"RANK", ps+, ("NO"|"YES"), ps+,
"SHORTTAG", ps+, ("NO"|"YES"|
(start-tag options, ps+, end-tag options, ps+, attribute-options)),
(ps+, empty element ending rules,
ps+, implied default declarations)?
[196.1] start-tag options =
"STARTTAG", ps+,
"EMPTY", ps+, ("NO"|"YES"), ps+,
"UNCLOSED", ps+, ("NO"|"YES"), ps+,
"NETENABL", ps+, ("NO"|"ALL"|"IMMEDNET")
where
EMPTY YES enables empty start-tags.
UNCLOSED YES enables unclosed start-tags.
NETENABL ALL permits NET-enabling start-tags and NULL end-tags; and
IMMEDNET restricts them to elements with empty syntactic content that
must be ended by a NET, so it cannot be specified if EMPTYNRM NO is
specified.
Note 12: An element with empty syntactic content need not have been declared EMPTY.
[196.2] end-tag options =
"ENDTAG", ps+,
"EMPTY", ps+, ("NO"|"YES"), ps+,
"UNCLOSED", ps+, ("NO"|"YES")
where
EMPTY YES enables empty end-tags.
UNCLOSED YES enables unclosed end-tags.
[196.3] attribute options =
"ATTRIB", ps+,
"DEFAULT", ps+, ("NO"|"YES"), ps+,
"OMITNAME", ps+, ("NO"|"YES"), ps+,
"VALUE", ps+, ("NO"|"YES")
where
DEFAULT YES enables attribute value defaulting (7.9.1.1).
OMITNAME YES allows attribute names and vi to be omitted for
unique NMTOKEN values (7.9.1.2).
VALUE YES allows some attribute values to be specified without
delimiters, rather than as literals (7.9.3.1).
Note 13: DEFAULT NO does not bar default values from attribute definition list declarations.
[196.4] empty element ending rules =
"EMPTYNRM", ps+, ("NO"|"YES")
where
EMPTYNRM YES applies normal rules for the presence of end-tags, including
markup minimization rules, to elements of a type declared EMPTY, or
that are forced to be EMPTY by an explicit content reference
attribute (7.3.).
Note 14: Specifying EMPTYNRM YES applies to mandatorily empty elements the same rules about the presence of end-tags that apply to other kinds of elements.
[196.5] implied default declarations =
"IMPLYDEF", ps+,
"ATTLIST", ps+, ("NO"|"YES"), ps+,
"DOCTYPE", ps+, ("NO"|"YES"), ps+,
"ELEMENT", ps+, ("NO"|"YES"), ps+,
"ENTITY", ps+, ("NO"|"YES"), ps+,
"NOTATION", ps+, ("NO"|"YES")
where
DOCTYPE YES means that an implied document type declaration includes
an implied declaration for an external subset entity (see K.4.9); and
YES for the other parameters allows information of the specified type
to be used in the document instance without an explicit declaration.
A declaration is implied, as follows:
ATTLIST YES means an undeclared attribute is declared as: CDATA #IMPLIED
ELEMENT YES means an undeclared element type is declared as: - - ANY
ENTITY YES means an undeclared general entity is declared as: SYSTEM
NOTATION YES means an undeclared notation is declared as: SYSTEM
Note 15: IMPLYDEF DOCTYPE YES implies only a declaration for an external subset entity. Other declarations may be implied if needed, and if permitted by the applicable IMPLYDEF parameters.
When IMPLYDEF ENTITY is specified, #DEFAULT cannot be specified as a general entity name.
Implicitly declared definitions occur in the grove in the order in which it is necessary to imply their declarations. No attribute assignment node is created for an attribute unless the attribute is specified.
Note 16: An implied declaration is not necessarily the same as an explicit declaration for the same object that was ignored during parsing (Note 29). Nor does it constrain any explicit declaration that might be created for that object as a result of processing (for example, when generating an explicit DTD for a document that has none).
[198] other features =
"OTHER", ps+,
"CONCUR", ps+, ("NO"|("YES", ps+, number)), ps+,
"SUBDOC", ps+, ("NO"|("YES", ps+, number)), ps+,
"FORMAL", ps+, ("NO"|"YES"),
(urn feature, keeprsre feature, validity feature, entities feature)?
[198.1] urn feature =
ps+, "URN", ps+, ("NO"|"YES")
where
URN YES means public identifiers are interpreted according to the
applicable Internet Engineering Task Force RFC2141 governing
Universal Resource Names.
If both URN and FORMAL are YES, public identifiers are interpreted either as formal public identifiers or as URNs.
[198.2] keeprsre feature =
ps+, "KEEPRSRE", ps+, ("YES"|"NO")
where
KEEPRSRE YES means clause 7.6.1 does not apply.
Note 17: If KEEPRSRE YES is specified, all white space in mixed content is included in the grove as datachar nodes.
Note 18: This option does not affect delimited strings, such as attribute value literals, which have their own rules for normalizing white space (and which, in any case, do not occur in content).
[198.3] validity feature = ps+,
"VALIDITY", ps+, ("NOASSERT"|"TYPE")
where
NOASSERT makes no validity assertion.
TYPE asserts that document instances are type-valid.
If the parameter is omitted, TYPE is assumed.
[198.4] entities feature = ps+,
"ENTITIES", ps+, ("NOASSERT"|
("REF", ps+, ("NONE"|"INTERNAL"|"ANY"), ps+,
"INTEGRAL", ps+, ("NO"|"YES")))
where
NOASSERT makes no validity assertion.
REF asserts the document either has unconstrained entity references (ANY),
is external-reference-free (INTERNAL), or is reference-free (NONE).
INTEGRAL YES asserts document instances are integrally-stored.
If the parameter is omitted, NOASSERT is assumed.
It is a reportable markup error if a document is less constrained than is asserted.
Note 19: For example, if an otherwise conforming document incorrectly asserts that it is integrally-stored, the document is non-conforming. Had the assertion not been made, the document would have been conforming.
Note 20: A system should offer means, such as a parameter to the invocation of processing, to check whether a particular VALIDITY or ENTITIES assertion could correctly be made for a document, even when the SGML declaration does not make that assertion.
Note 21: To satisfy the classical requirement for SGML conformance, a document instance must be fully-declared using only markup declarations, as well as type-valid.
[199.1] added requirements =
"SEEALSO", ps+, ("NONE"| (ps+, public identifier)+)
The public identifiers identify additional requirements for the document, including requirements unrelated to the SGML language. These requirements are in addition to, and must not contradict, the requirements of this International Standard. Failure to satisfy the added requirements is not a reportable markup error, except to the extent that such requirements are also expressed in other parameters of the SGML declaration.
Note 22: For example, this parameter could be used by an SGML system to signal the existence of requirements for specific entity constraint assertions, formatting conventions for specified element types, or data restrictions, such as that the number of cells in a table row does not exceed the number specified in some attribute. It is not a reportable markup error if the added required entity assertions are not present in the SGML declaration; if they are present, it is a reportable markup error if the the document fails to satisfy them, as that would have been the case even in the absence of the added requirements.
It is not an error if the system is unable to access an object named by the public identifiers.
Note 23: See Annex L "Added Requirements for XML" for an example.
[62] character reference = named character reference | numeric character reference | hex character reference [62.1] named character reference = cro, function name, reference end [62.2] numeric character reference = cro, character number, reference end [62.3] hex character reference = hcro, hexdigit+, reference end
A hexdigit is a digit or lowercase a-f or uppercase A-F. The length of the hex digit string cannot exceed NAMELEN.
Name String Number Mode Constraint Description HCRO (none) (none) CON LIT HEX Hex character reference open NESTC (NET) (none) TAG NET-enabling start-tag close NET / 47 CON ELEM Null end-tag
HEX constraint: must be followed by a hexdigit.
If no assignment is made to NESTC, the NET is used.
[18] net-enabling start-tag = stago, generic identifier specification, attribute specification list, s*, nestc
[141] attribute definition list declaration =
mdo, "ATTLIST", ps+,
((associated element type | (rni, ("IMPLICIT"|"ALL")))|
(rni, "NOTATION", ps+,
(associated notation name | (rni, ("IMPLICIT"|"ALL"))))), ps+,
attribute definition list,
ps*, mdc
where the keywords indicate the objects associated with the attributes:
NOTATION indicates that the associated objects are notations.
IMPLICIT means all the implicitly defined element types or notations.
ALL means all element types or notations.
[149.1] associated notation name =
(notation name | name group)
IMPLICIT and ALL are the equivalent of name groups.
The same element type or notation may be the associated object in multiple ATTLIST declarations. An attempt to redefine an attribute that was previously defined for an associated object is not an error; the earliest definition prevails (just as for entity declarations). However, a definition associated with ALL can be overridden by subsequent attribute declarations for specific element types or notations (including declarations specified with IMPLICIT), except when the attribute has already been specified. It is therefore an error to specify a data attribute that was declared with ALL and then to attempt to redeclare that attribute.
[142] attribute definition list = attribute definition?, (ps+, attribute definition)*
[145] declared value = "CDATA"|"ENTITY"|"ENTITIES"|"ID"|"IDREF"|"IDREFS"|"NAME"|"NAMES"| "NMTOKEN"|"NMTOKENS"|"NUMBER"|"NUMBERS"|"NUTOKEN"|"NUTOKENS"| notation|name token group|data specification [145.1] data specification = "DATA", ps+, notation name, data attribute specification? where "notation name" identifies the data content notation of the attribute's value "data attribute specification" specifies the corresponding data attributes
The value of an attribute whose declared value is "data specification" is character data.
Note 24: An application may wish to verify that the value of a data specification attribute is meaningful in light of the specified notation name and data attributes, but it is not an SGML error if this is not the case.
[111] document type name = (generic identifier | (rni, "IMPLIED")) where IMPLIED means the document element can have any valid element type name.
It is a reportable markup error if IMPLIED is specified and the start-tag of the document element is omitted or does not contain a generic identifier.
IMPLIED cannot be specified if LINK EXPLICIT YES or CONCUR YES are specified in the SGML declaration.
[80] owner identifier = ISO owner identifier | registered owner identifier | unregistered owner identifier | internet domain name owner identifier [83.1] internet domain name owner identifier = "+//IDN ", minimum data where the minimum data must begin with an internet domain name.
Note 25: The string "IDN domain.name" is treated as an ISO/IEC 9070 "registered owner prefix". Any sub-domain names could be expressed as owner name components. For example, the internet domain name in "http://www.someisp.net/users/mtb" could occur in an FPI as:
+//IDN someisp.net::www::users::mtbor as:
+//IDN www.someisp.net/users/mtb
Note 26: When constructing a public text owner identifier using an internet domain name, users may wish to consider the name's potential lifespan and that of the objects to be identified by public identifiers that use it.
Semicolon, exclamation point, asterisk, number sign, commercial at sign, dollar sign, underscore, and percent sign are members of the abstract character class "special", which is usable in minimum data.
An element of a type declared EMPTY, or that is forced to be EMPTY by an explicit content reference attribute, cannot contain any text, including white space, other markup, or included subelements. Markup minimization can be applied to such elements (7.3).
A referenced parameter entity must consist of zero or more of the consecutive complete tokens that follow the ts in which the reference occurs in the same group (i.e., at the same nesting level), together with any intervening ts separators and connectors, and optionally with surrounding separators and connectors. The entity must end within the same group.
An Ee can occur in a ts only if the reference to the entity the Ee terminates occurs in the same group (i.e., at the same nesting level).
[113] entity set = (entity declaration | attribute definition list declaration | notation declaration | ds)* where The keyword "NOTATION" must be specified in the attribute definition list declaration.
[3] SGML subdocument entity = (s*, SGML declaration)?, prolog, document instance set, Ee
If the SGML declaration is omitted, the subdocument uses the SGML declaration applicable to the entity from which the subdocument entity is referenced.
If LINK EXPLICIT NO and CONCUR NO are specified in the SGML declaration and either or both of IMPLYDEF DOCTYPE YES or IMPLYDEF ELEMENT YES are specified, the SGML document entity need not contain a prolog. In such cases, a prolog will be implied consisting solely of a single implied document type declaration, as follows:
<!DOCTYPE #IMPLIED SYSTEM []>
<!DOCTYPE #IMPLIED []>
Note 27: When both the document type name and the external subset entity are implied in a document type declaration, a system may be able to locate an appropriate external subset by considering the storage identifier of the SGML document entity and/or the generic identifier of the document element.
If permitted by the implied default declarations parameter of the SGML declaration, a document type declaration (whether explicit or implied) may lack declarations for element types, attributes, notations, and/or general entities. Declarations are implied for them as provided in K.3.7.
Note 28: Care should be taken to insure that markup minimization in the instance does not obscure the element structure and cause the parser to misunderstand the intended implied declarations.
Note 29: If some or all of an instance's associated document type declaration should be unavailable or for other reasons ignored during parsing, it is recommended that the constructed grove be the same as if implied declarations had replaced the ignored ones.
Add new clause:
K.4.10 DTD data entities
K.4.10.1 DTD notations
To the extent that an SGML system can recognize properties expressed by DTD notations, it shall treat them identically to DTD properties that are expressed by markup declarations.
It is a reportable markup error if a DTD entity is referenced and its representation of required DTD properties is not understood by the system and it is not permissible to imply default declarations for them.
Note 4: Therefore, when implied default declarations are permitted, the use of a DTD notation that cannot be understood has the same effect as omitting the equivalent markup declarations.
K.4.10.2 External parameter entity declaration (10.5.5)
The declaration of an external parameter entity can include an entity type that specifies the name of a data notation.
K.4.10.3 External subset entity
Production 110 is replaced with:
[110] document type declaration = mdo, "DOCTYPE", ps+, document type name, (ps+, external identifier, (ps+, ("CDATA"|"NDATA"|"SDATA"), ps+, notation name)?)?, (ps+, dso, document type declaration subset, dsc)?, ps*, mdcThe notation name must be declared within the internal subset of the document type declaration.
Note 5: If data attributes are to be specified for a DTD data entity, an external parameter entity must be used rather than an external subset entity.
Add new clause:
K.4.11 Content model (11.2.4, 11.2.5)
[129] primitive content token = ( rni , ("PCDATA" | "ALL" | "IMPLICIT")) | element token | data tag group where ALL and IMPLICIT have the same meaning as in K.4.4 and are equivalent to optional repeatable OR groups.#ALL and #IMPLICIT are allowed in the name groups in [139] and [140]. They have the same meaning as in K.4.4.
This annex illustrates the relationship of SGML declarations to "added requirements" by means of a real-world example, XML. It is not intended as a specification for XML.
The Extensible Markup Language (XML) is the core subset of SGML functionality developed by the World Wide Web Consortium (W3C) for exchanging SGML documents over the World Wide Web. The current specification for XML can be found at the W3C web site at "http://www.w3.org/TR/" under the title "Extensible Markup Language (XML).
The XML specification covers the following aspects of an SGML application and system:
XML distinguishes two classes of conforming documents:
A full-SGML validating parser cannot validate documents for conformance to XML unless it is specially modified to support XML. That is because some of XML's language restrictions cannot be expressed in the SGML declaration. Those restrictions can be found in http://www.w3.org/TR/NOTE-sgml-xml.
XML documents implicitly contain an SGML declaration, which differs slightly depending on whether the document is "valid". XML documents that are well-formed but not valid implicitly contain the following SGML declaration.
<!SGML -- SGML Declaration for XML --
"ISO 8879:1986 (WWW)"
CHARSET
BASESET
"ISO Registration Number 176//CHARSET
ISO/IEC 10646-1:1993 UCS-4 with implementation
level 3//ESC 2/5 2/15 4/6"
DESCSET
0 9 UNUSED
9 2 9
11 2 UNUSED
13 1 13
14 18 UNUSED
32 95 32
127 1 UNUSED
128 32 UNUSED
160 55136 160
55296 2048 UNUSED -- surrogates --
57344 8190 57344
65534 2 UNUSED -- FFFE and FFFF --
65536 1048576 65536
CAPACITY NONE
SCOPE DOCUMENT
SYNTAX
SHUNCHAR NONE
BASESET "ISO Registration Number 176//CHARSET
ISO/IEC 10646-1:1993 UCS-4 with implementation
level 3//ESC 2/5 2/15 4/6"
DESCSET
0 1114112 0
FUNCTION
RE 13
RS 10
SPACE 32
TAB SEPCHAR 9
NAMING
LCNMSTRT ""
UCNMSTRT ""
NAMESTRT
58 95 192-214 216-246 248-305 308-318 321-328
330-382 384-451 461-496 500-501 506-535 592-680
699-705 902 904-906 908 910-929 931-974 976-982
986 988 990 992 994-1011 1025-1036 1038-1103
1105-1116 1118-1153 1168-1220 1223-1224
1227-1228 1232-1259 1262-1269 1272-1273
1329-1366 1369 1377-1414 1488-1514 1520-1522
1569-1594 1601-1610 1649-1719 1722-1726
1728-1742 1744-1747 1749 1765-1766 2309-2361
2365 2392-2401 2437-2444 2447-2448 2451-2472
2474-2480 2482 2486-2489 2524-2525 2527-2529
2544-2545 2565-2570 2575-2576 2579-2600
2602-2608 2610-2611 2613-2614 2616-2617
2649-2652 2654 2674-2676 2693-2699 2701
2703-2705 2707-2728 2730-2736 2738-2739
2741-2745 2749 2784 2821-2828 2831-2832
2835-2856 2858-2864 2866-2867 2870-2873 2877
2908-2909 2911-2913 2949-2954 2958-2960
2962-2965 2969-2970 2972 2974-2975 2979-2980
2984-2986 2990-2997 2999-3001 3077-3084
3086-3088 3090-3112 3114-3123 3125-3129
3168-3169 3205-3212 3214-3216 3218-3240
3242-3251 3253-3257 3294 3296-3297 3333-3340
3342-3344 3346-3368 3370-3385 3424-3425
3585-3630 3632 3634-3635 3648-3653 3713-3714
3716 3719-3720 3722 3725 3732-3735 3737-3743
3745-3747 3749 3751 3754-3755 3757-3758 3760
3762-3763 3773 3776-3780 3904-3911 3913-3945
4256-4293 4304-4342 4352 4354-4355 4357-4359
4361 4363-4364 4366-4370 4412 4414 4416 4428
4430 4432 4436-4437 4441 4447-4449 4451 4453
4455 4457 4461-4462 4466-4467 4469 4510 4520
4523 4526-4527 4535-4536 4538 4540-4546 4587
4592 4601 7680-7835 7840-7929 7936-7957
7960-7965 7968-8005 8008-8013 8016-8023 8025
8027 8029 8031-8061 8064-8116 8118-8124 8126
8130-8132 8134-8140 8144-8147 8150-8155
8160-8172 8178-8180 8182-8188 8486 8490-8491
8494 8576-8578 12295 12321-12329 12353-12436
12449-12538 12549-12588 19968-40869 44032-55203
LCNMCHAR ""
UCNMCHAR ""
NAMECHAR
45-46 183 720-721 768-837 864-865 903 1155-1158
1425-1441 1443-1465 1467-1469 1471 1473-1474
1476 1600 1611-1618 1632-1641 1648 1750-1764
1767-1768 1770-1773 1776-1785 2305-2307 2364
2366-2381 2385-2388 2402-2403 2406-2415
2433-2435 2492 2494-2500 2503-2504 2507-2509
2519 2530-2531 2534-2543 2562 2620 2622-2626
2631-2632 2635-2637 2662-2673 2689-2691 2748
2750-2757 2759-2761 2763-2765 2790-2799
2817-2819 2876 2878-2883 2887-2888 2891-2893
2902-2903 2918-2927 2946-2947 3006-3010
3014-3016 3018-3021 3031 3047-3055 3073-3075
3134-3140 3142-3144 3146-3149 3157-3158
3174-3183 3202-3203 3262-3268 3270-3272
3274-3277 3285-3286 3302-3311 3330-3331
3390-3395 3398-3400 3402-3405 3415 3430-3439
3633 3636-3642 3654-3662 3664-3673 3761
3764-3769 3771-3772 3782 3784-3789 3792-3801
3864-3865 3872-3881 3893 3895 3897 3902-3903
3953-3972 3974-3979 3984-3989 3991 3993-4013
4017-4023 4025 8400-8412 8417 12293 12330-12335
12337-12341 12441-12442 12445-12446 12540-12542
NAMECASE GENERAL NO ENTITY NO
DELIM
GENERAL SGMLREF
HCRO "&#x"
-- Ampersand followed by "#38;#x" (without quotes) --
NESTC "/"
NET ">"
PIC "?>"
SHORTREF NONE
NAMES SGMLREF
QUANTITY NONE
ENTITIES "amp" 38 "lt" 60 "gt" 62 "quot" 34 "apos" 39
FEATURES
MINIMIZE
DATATAG NO
OMITTAG NO
RANK NO
SHORTTAG
STARTTAG EMPTY NO UNCLOSED NO NETENABL IMMEDNET
ENDTAG EMPTY NO UNCLOSED NO
ATTRIB DEFAULT YES OMITNAME NO VALUE NO
EMPTYNRM YES
IMPLYDEF ATTLIST YES DOCTYPE NO ELEMENT YES
ENTITY NO NOTATION NO
LINK SIMPLE NO IMPLICIT NO EXPLICIT NO
OTHER CONCUR NO SUBDOC NO FORMAL NO URN NO
KEEPRSRE YES VALIDITY NOASSERT ENTITIES REF ANY INTEGRAL YES
APPINFO NONE
SEEALSO "ISO 8879:1986//NOTATION
Extensible Markup Language (XML) 1.0//EN"
>
The SGML declaration for valid XML documents differs in the following parameters.
FEATURES
MINIMIZE
IMPLYDEF ATTLIST NO ELEMENT NO
OTHER VALIDITY TYPE