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This electronic document is for use during development and review of International Standards. Official printed copies of International Standards can be purchased from the ISO and the national standards organization of your country.

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6 Base module

6.3 HyTime support declarations

A document may indicate conformance to HyTime by following the procedures in A.3.3.1 Enabling architecture use of APPINFO parameter. That is, the APPINFO parameter of the SGML declaration declares the existence of an ArcBase declaration, which identifies the HyTime architecture support declarations.

NOTE 93 The use of APPINFO serves to declare the use of architectures and HyTime within SGML declarations. However, it is sufficient to enable architectural processing to declare the use of HyTime with the ArcBase processing instruction within DOCTYPE declarations.

The support declarations include support attributes that are defined for all architectures. They are discussed in A.3.4 Architecture support declarations.

The support attributes for HyTime include support attributes for each module that control the use of optional facilities that affect the syntax of the HyTime meta-DTD. Additional support attributes control the use of facilities that have semantic, but not syntactic, implications.

There is a facility support attribute named after each module. The attribute value contains the names of the module's optional facilities for which support is being declared. If only the module name is specified, then only support of the module's mandatory facilities is declared, if any (some modules have no mandatory facilities). If other facilities are specified then support for the module is implied and need not be specified. If the specified attribute value is the empty string ("") or the attribute is not specified at all and the default value declared in the notation attribute declaration list is "#IMPLIED", then the module is not declared at all.

NOTE 94 For example, the following attributes declare that support is required for the optional desctxt facility of the base module and the non-optional facilities of the sched module. The links and rendition modules are not required at all. 

base="desctxt" sched="sched"

Some options require qualification in addition to stating their support. For these options, separate attributes are provided where the attribute name is the name of the option, for example: 

manyaxes="3"
When an option qualification attribute sets limits, if no value is specified, there is no limit for that option. Option-specific attributes are ignored if the option to which they apply is not supported.

The attribute highest quantum count limit (hyqcnt) declares a limit that no quantum count in the document instance will exceed, including the FCS dimensions of coordinate axes and the number of nodes in node lists. The hyqcnt is specified as a power of two that exceeds the limit. The HyTime default (and the minimum for any use of HyTime) is 4,294,967,295.

NOTE 95 In other words, when the default hyqcnt is used, a HyTime implementation is never required to accumulate a quantum count greater than the capacity of an unsigned 32-bit integer: (2**32)-1.

An application designer is required to choose granularities that will not cause this limit to be exceeded.

NOTE 96 The hyqcnt gives the application designer wide latitude in specifying the precision of HyTime coordinate addressing. For this reason, HyTime's use of finite quanta rather than infinite points does not restrict HyTime applications in any practical way.

The attribute any SGML declaration allowed (anysgml) specifies whether (anysgml) or not (nanysgml) the HyTime processor allows members of a hyperdocument to use different SGML declarations. When the value is "nanysgml", all SGML documents in the hyperdocument must conform to the same SGML declaration.

The attribute external references allowed (exrefs) specifies whether (exrefs) or not (nexrefs) external references are allowed. When external references are not allowed, all location addressing (except direct entity reference) must be to objects within the document from which the reference is made. The default is to allow external references. This option is ignored if the location address module is not supported.

The attribute SGML model groups for reftype (refmodel) specifies whether (SGMLmdl) or not (nSGMLmdl) reftype attributes may specify any valid SGML content model or are limited to repeating OR groups of element type names.

The attribute maximum number of anchors allowed in hyperlinks (manyanch) specifies the maximum number of anchors allowed for hyperlink instances. If the value is unspecified or is zero, the number of anchors is unlimited. This option is ignored if the hyperlinks module is not supported.

The attribute maximum number of axes allowed in coordinate spaces (manyaxes) specifies the maximum number of axes allowed for finite coordinate spaces. If the value is unspecified or is zero, the number of axes is unlimited. This option is ignored if the scheduling module is not supported.

The complete set of facility attributes, with all options supported, is: 

                 <!-- HyTime Support Declarations -->
<?IS10744 ArcBase HyTime>
<!NOTATION
   HyTime         -- HyTime Architecture --
                  -- A base architecture used in conformance with the
                     Architectural Form Definition Requirements of
                     International Standard ISO/IEC 10744. --

   PUBLIC "ISO/IEC 10744:1997//NOTATION AFDR ARCBASE
           Hypermedia/Time-based Structuring Language (HyTime)//EN"
>
<!ATTLIST #NOTATION HyTime
   ArcFormA NAME     HyTime
   ArcNamrA NAME     HyNames
   ArcSuprA NAME     sHyTime
   ArcIgnDA NAME     HyIgnD
   ArcDocF  NAME     #FIXED HyDoc
   ArcDTD   CDATA    "HyTime"

   -- NAMELEN must be at least 9 because the HyTime meta-DTD uses
      8-character parameter entity names. --
   ArcQuant CDATA    #FIXED "NAMELEN 9"

   ArcDataF NAME     #FIXED HyBridN
   ArcBridF NAME     #FIXED HyBrid

   -- For some HyTime forms, the generic identifiers of client elements
      are meaningful to a HyTime engine and must be customized.
      Therefore, automatic form mapping may be inappropriate. --
   ArcAuto  (ArcAuto|nArcAuto) nArcAuto

   ArcOptSA NAMES    "GenArc base links locs rend sched"

   GenArc         -- General architecture facilities --
      CDATA       -- Lextype: csname+ --
      "altreps dafe dvlist HyLex HyOrd included ireftype lextype
       opacity REGEX superdcn"

   base           -- Base module facilities --
      CDATA       -- Lextype: csname+ --
      "activity actypes bos bosspec conloc desctxt dimspec HyDimLst
       HyDimSpc HyFunk markfun valueref"

   locs           -- Location address module facilities --
                  -- Clause: 6.3 --
      CDATA       -- Lextype: csname+ --
      "agrovdef bibloc dataloc datatok grovplan listloc mixedloc
       multloc nameloc nmsploc pathloc pgrovdef proploc queryloc
       refctl referatt refloc reftype relloc spanloc treecom treeloc
       treetype"

   links          -- Hyperlinks module facilities --
                  -- Clause: 6.3 --
      CDATA       -- Lextype: csname+ --
      "agglink anchloc clink hylink ilink linkloc traverse varlink"

   sched          -- Scheduling module facilities --
                  -- Clause: 6.3 --
      CDATA       -- Lextype: csname+ --
      "calibrat calspec dimref fcsloc grpdex grprepet HyCalSpc
       HyExSpec HyExtLst HyGrand measure objalign pulsemap sched"

   rend           -- Rendition module facilities --
                  -- Clause: 6.3 --
      CDATA       -- Lextype: csname+ --
      "baton batonseq HyDimPro HyExPro HyPro modify obextent patch
       project proseq wand wndpatch"

   anysgml        -- Any SGML declaration allowed --
                  -- Clause: 6.3 --
      (anysgml|nanysgml)
      nanysgml

   exrefs         -- External references allowed --
                  -- Clause: 6.3 --
      (exrefs|nexrefs)
      exrefs

   refmodel       -- SGML model groups for reftype --
                  -- Clause: 6.3 --
      (SGMLmdl|nSGMLmdl)
      nSGMLmdl

   hyqcnt         -- Highest quantum count limit --
                  -- Clause: 6.3 --
      NUMBER      -- Constraint: power of 2 >= 32  --
      32

   manyanch       -- Maximum number of anchors allowed in
                     hyperlinks --
                  -- Clause: 6.3 --
      NUMBER      -- Constraint: must be >= 2 --
      #IMPLIED    -- Default: no limit --

   manyaxes       -- Maximum number of axes allowed in coordinate
                     spaces --
                  -- Clause: 6.3 --
      NUMBER      -- Constraint: must be >= 1 --
      #IMPLIED    -- Default: no limit --
>
<!NOTATION AFDRMeta
   PUBLIC "ISO/IEC 10744:1997//NOTATION AFDR Meta-DTD Notation//EN"
>
<!ENTITY
   HyTime         -- HyTime meta-DTD --
                  -- Clause: 6.3 --

   PUBLIC "ISO/IEC 10744:1997//DTD AFDR Meta-DTD
           Hypermedia/Time-based Structuring Language (HyTime)//EN"

   CDATA AFDRMeta
>

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Copyright © 1992, 1997 International Organization for Standardization. All rights reserved.

This electronic document is for use during development and review of International Standards. Official printed copies of International Standards can be purchased from the ISO and the national standards organization of your country.

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