The system declaration for MacSgmls is as follows:
| <!SYSTEM "ISO 8879:1986"
| --document character set--
| CHARSET
| --base character set--
| BASESET "ISO 646-1983//CHARSET International Reference Version (IRV)//ESC 2/5 4/0"
| --described character portion--
| DESCSET 0 128 0
| --capacity set--
| CAPACITY PUBLIC "ISO 8879:1986//CAPACITY Reference//EN"
| --feature use--
| FEATURES
| --markup minimization features--
| MINIMIZE
| DATATAG NO --data characters may serve simultaneously as tags--
| OMITTAG YES --some tags may be omitted altogether--
| RANK NO --element ranks may be omitted from tags--
| SHORTTAG YES --short tags with omitted delimiters, attribute specifications, or generic identifier may be used--
| --link type features--
| LINK
| SIMPLE NO --simple link process definitions may be used--
| IMPLICIT NO --implicit link process definitions may be used--
| EXPLICIT NO --explicit link process definitions may be used and longest chain of link process has the specific number of links--
| --other features--
| OTHER
| CONCUR NO --instances of the specified number of document types may occur concurrently with an instance of the base document type--
| SUBDOC YES 1 --the spcified number of SGML subdocument entities may be open at one time--
| FORMAL YES --that public identifiers are interpreted as formal public identifiers--
| --concrete syntax scope--
| SCOPE DOCUMENT
| --concrete syntax--
| SYNTAX PUBLIC "ISO 8879:1986//SYNTAX Reference//EN"
| SYNTAX PUBLIC "ISO 8879:1986//SYNTAX Core//EN"
| --validation services--
| VALIDATE
| GENERAL YES --a reportable markup error will be found and reported--
| MODEL YES --an ambiguous content model will be reported--
| EXCLUDE YES --an exclusion that could change a group's required or optional status in a model will be reported--
| CAPACITY YES --that exceeding a capacity limit will be reported--
| NONSGML YES --the occurrence of at least one non-SGML character, but not necessarily all, will be reported--
| SGML YES --an error in the SGML declaration will be reported--
| FORMAL YES --a formal public identifier error will be reported--
| --SDIF supprt--
| SDIF
| PACK NO --making from one or more entities to SDIF data string--
| UNPACK NO --breaking up SDIF data string into entities of constituent elements--
| >
The memory usage of MacSgmls is not a function of the capacity points used by a document; however, MacSgmls can handle capacities significantly greater than the reference capacity set.
Documents that do not use optional features are also supported. For example, if FORMAL NO is specified in the SGML declaration, public identifiers will not be required to be valid formal public identifiers.
Certain parts of the concrete syntax may be changed:
The shunned character numbers can be changed.
Eight bit characters can be assigned to LCNMSTRT, UCNMSTRT, LCNMCHAR and UCNMCHAR. Declaring this requires that the syntax reference character set be declared like this:
| BASESET "ISO Registration Number 100//CHARSET ECMA-94 Right Part of Latin Alphabet Nr. 1//ESC 2/13 4/1"
| DESCSET 0 256 0
Uppercase substitution can be performed or not performed both for entity names and for other names.
Either short reference delimiters assigned by the reference delimiter set or no short reference delimiters are supported.
The reserved names can be changed.
The quantity set can be increased within certain limits subject to there being sufficient memory available. The upper limit on NAMELEN is 239. The upper limits on ATTCNT, ATTSPLEN, BSEQLEN, ENTLVL, LITLEN, PILEN, TAGLEN, and TAGLVL are more than thirty times greater than the reference limits. The upper limit on GRPCNT, GRPGTCNT, and GRPLVL is 253. NORMSEP cannot be changed. DTAGLEN are DTEMPLEN irrelevant since MacSgmls does not support the DATATAG feature.
