An SGML System Conforming to International Standard ISO 8879 --
Standard Generalized Markup Language


nsgmls [ -BCdeglprsuv ] [ -alinktype ] [ -bbctf ] [ -csysid ] [ -Ddirectory ] [ -Emax_errors ] [ -ffile ] [ -iname ] [ -ooutput_option ] [ -tfile ] [ -wwarning_type ] [ sysid... ]


Nsgmls parses and validates the SGML document whose document entity is specified by the system identifiers sysid... and prints on the standard output a simple text representation of its Element Structure Information Set. (This is the information set which a structure-controlled conforming SGML application should act upon.) If more than one system identifier is specified, then the corresponding entities will be concatenated to form the document entity. Thus the document entity may be spread amongst several files; for example, the SGML declaration, prolog and document instance set could each be in a separate file. If no system identifiers are specified, then nsgmls will read the document entity from the standard input. A command line system identifier of - can be used to refer to the standard input. (Normally in a system identifier, <osfd>0 is used to refer to standard input.)


The following options are available:

Make link type linktype active. Not all ESIS information is output in this case: the active LPDs are not explicitly reported, although each link attribute is qualified with its link type name; there is no information about result elements; when there are multiple link rules applicable to the current element, nsgmls always chooses the first.
This determines the encoding used for output. If in fixed character set mode it specifies the name of an encoding; if not, it specifies the name of a BCTF.
Batch mode. Parse each sysid... specified on the command line separately, rather than concatenating them. This is useful mainly with -s.

If -tfilename is also specified, then the specified filename will be prefixed to the sysid to make the filename for the RAST result for each sysid.

Map public identifiers and entity names to system identifiers using the catalog entry file whose system identifier is sysid. Multiple -c options are allowed. If there is a catalog entry file called catalog in the same place as the document entity, it will be searched for immediately after those specified by -c.
The filename... arguments specify catalog files rather than the document entity. The document entity is specified by the first DOCUMENT entry in the catalog files.
Search directory for files specified in system identifiers. Multiple -D options are allowed. See the description of the osfile storage manager for more information about file searching.
Describe open entities in error messages. Error messages always include the position of the most recently opened external entity.
Nsgmls will exit after max_errors errors. If max_errors is 0, there is no limit on the number of errors. The default is 200.
Redirect errors to file. This is useful mainly with shells that do not support redirection of stderr.
Show the generic identifiers of open elements in error messages.
Pretend that
<!ENTITY % name "INCLUDE">

occurs at the start of the document type declaration subset in the SGML document entity. Since repeated definitions of an entity are ignored, this definition will take precedence over any other definitions of this entity in the document type declaration. Multiple -i options are allowed. If the SGML declaration replaces the reserved name INCLUDE then the new reserved name will be the replacement text of the entity. Typically the document type declaration will contain

<!ENTITY % name "IGNORE">

and will use %name; in the status keyword specification of a marked section declaration. In this case the effect of the option will be to cause the marked section not to be ignored.

Output additional information accordig to output_option:
Output definitions of all general entities not just for data or subdoc entities that are referenced or named in an ENTITY or ENTITIES attribute.
Distinguish attributes whose declared value is ID.
Output L commands giving the current line number and filename.
Output an i command for included subelements.
Output an e command for elements which are not allowed to have an end-tag, that is those with a declared content of empty or with a content reference attribute.
Output an f command before an N command, if a system identifier could be generated for that notation.
In fixed character set mode, output \% escape sequences for non-SGML data characters. Non-SGML data characters can result from numeric character references.

Multiple -o options are allowed.

Parse only the prolog. Nsgmls will exit after parsing the document type declaration. Implies -s.
Suppress output. Error messages will still be printed.
Output to file the RAST result as defined by ISO/IEC 13673:1995 (actually this isn't quite an IS yet; this implements the Intermediate Editor's Draft of 1994/08/29, with changes to implement ISO/IEC JTC1/SC18/WG8 N1777). The normal output is not produced.
Print the version number.
Control warnings and errors. Multiple -w options are allowed. The following values of type enable warnings:
Warn about constructs that are not allowed by XML.
Warn about mixed content models that do not allow #pcdata anywhere.
Warn about various dubious constructions in the SGML declaration.
Warn about various recommendations made in ISO 8879 that the document does not comply with. (Recommendations are expressed with ``should'', as distinct from requirements which are usually expressed with ``shall''.)
Warn about defaulted references.
Warn about duplicate entity declarations.
Warn about undefined elements: elements used in the DTD but not defined.
Warn about unclosed start and end-tags.
Warn about empty start and end-tags.
Warn about net-enabling start-tags and null end-tags.
Warn about minimized start and end-tags. Equivalent to combination of unclosed, empty and net warnings.
Warn about unused short reference maps: maps that are declared with a short reference mapping declaration but never used in a short reference use declaration in the DTD.
Warn about parameter entities that are defined but not used in a DTD. Unused internal parameter entities whose text is INCLUDE or IGNORE won't get the warning.
Warn about notations for which no system identifier could be generated.
Warn about conditions that should usually be avoided (in the opinion of the author). Equivalent to: mixed, should, default, undefined, sgmldecl, unused-map, unused-param, empty and unclosed.

A warning can be disabled by using its name prefixed with no-. Thus -wall -wno-duplicate will enable all warnings except those about duplicate entity declarations.

The following values for warning_type disable errors:

Do not give an error for an ID reference value which no element has as its ID. The effect will be as if each attribute declared as an ID reference value had been declared as a name.
Do not give an error when a character that is not a significant character in the reference concrete syntax occurs in a literal in the SGML declaration. This may be useful in conjunction with certain buggy test suites.
Do not require the document to be type-valid. This has the effect of changing the SGML declaration to specify VALIDITY NOASSERT and IMPLYDEF ATTLIST YES ELEMENT YES. An option of -wvalid has the effect of changing the SGML declaration to specify VALIDITY TYPE and IMPLYDEF ATTLIST NO ELEMENT NO. If neither -wvalid nor -wno-valid are specified, then the VALIDITY and IMPLYDEF specified in the SGML declaration will be used.

The following options are also supported for backwards compatibility with sgmls:

Same as -wduplicate.
Same as -oline.
Same as -c.
Same as -wdefault.
Same as -wundef.

James Clark