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OpenSP - Catalogs
Catalogs
The entity manager generates a system identifier for every external
entity using catalog entry files in the format defined by SGML Open
Technical Resolution TR9401:1997. The entity manager will give an
error if it is unable to generate a system identifier for an external
entity. Normally if the external identifier for an entity includes a
system identifier then the entity manager will use that as the
effective system identifier for the entity; this behaviour can be
changed using OVERRIDE or SYSTEM entries in
a catalog entry file.
A catalog entry file contains a sequence of entries in one of the
following forms:
-
PUBLIC pubid sysid
-
This specifies that sysid should be used as
the effective system identifier if the public identifier is
pubid. Sysid is a
system identifier as defined in ISO 8879 and
pubid is a public identifier as defined in ISO
8879.
-
ENTITY name sysid
-
This specifies that sysid should be used as the effective
system identifier if the entity is a general entity whose name is
name.
-
ENTITY %name sysid
-
This specifies that sysid should be used as
the effective system identifier if the entity is a parameter entity
whose name is name. Note that there is no space between
the % and the name.
-
DOCTYPE name sysid
-
This specifies that sysid should be used as
the effective system identifier if the entity is an entity declared in
a document type declaration whose document type name is name.
-
LINKTYPE name sysid
-
This specifies that sysid should be used as the
effective system identifier if the entity is an entity declared in a
link type declaration whose link type name is name.
-
NOTATION name sysid
-
This specifies that sysid should be used as
the effective system identifier for a notation whose name is
name.
This is relevant only with the -n option.
-
OVERRIDE bool
-
bool may be YES or
NO. This sets the overriding mode for entries up to the
next occurrence of OVERRIDE or the end of the catalog entry file. At
the beginning of a catalog entry file the overriding mode will be NO.
A PUBLIC, ENTITY, DOCTYPE, LINKTYPE or NOTATION entry with an
overriding mode of YES will be used whether or not the external
identifier has an explicit system identifier; those with an overriding
mode of NO will be ignored if external identifier has an explicit
system identifier.
-
SYSTEM sysid1 sysid2
-
This specifies that sysid2 should be used as the effective
system identifier if the system identifier specified in the external
identifier was sysid1.
sysid2 should always be quoted to
ensure that it is not misinterpreted when parsed by a system that does
not support this extension.
-
SGMLDECL sysid
-
This specifies that if the document does not contain an SGML declaration,
the SGML declaration in sysid should be implied.
-
DTDDECL pubid sysid
-
This specifies that if the document does not contain an SGML declaration
and uses a doctype declaration with public identifier
pubid, the SGML declaration in
sysid should be implied.
-
DOCUMENT sysid
-
This specifies that the document entity is sysid.
This entry is used only with the -C option.
-
CATALOG sysid
-
This specifies that sysid is the system
identifier of an additional catalog entry file to be read after this
one. Multiple CATALOG entries are allowed and will be
read in order.
-
BASE sysid
-
This specifies that relative storage object identifiers in system
identifiers in the catalog entry file following this entry should be
resolved using first storage object identifier in
sysid as the base, instead of the storage
object identifiers of the storage objects comprising the catalog entry
file.
Note that the
sysid must exist.
-
DELEGATE pubid-prefix sysid
-
This specifies that entities with a public identifier that has
pubid-prefix as a prefix should be resolved
using a catalog whose system identfier is
sysid. For more details, see A Proposal for
Delegating SGML Open Catalogs.
-
SGML name sysid
-
This specifies that the SGML declaration body in sysid
should be used when the document starts with a reference to an SGML
declaration named name. This is an OpenSP-specific
extension of the SGML Open catalog format. SGML declaration references
are defined in
Annex K of ISO 8879.
The delimiters can be omitted from the sysid
provided it does not contain any white space. Comments are allowed
between parameters delimited by -- as in SGML.
The entity manager will look for catalog entry files as follows:
-
a file called catalog in the same directory as the
document entity, unless the environment variable
SP_USE_DOCUMENT_CATALOG has the value NO or
0;
-
any catalog entry files specified using the -c option;
-
a list of files specified by the environment variable
SGML_CATALOG_FILES; the list is separated by colons under
Unix and by semi-colons under MS-DOS and Windows; if this environment
variable is not set, then a system dependent list of catalog entry
files will be used.
In fact catalog entry files are not restricted to being files: the
name of a catalog entry file is interpreted as a system identifier.
A match in one catalog entry file will take precedence over any match
in a later catalog entry file. A more specific matching entry in one
catalog entry file will take priority over a less specific matching
entry in the same catalog entry file. For this purpose, the order of
specificity is (most specific first):
-
SYSTEM entries;
-
PUBLIC entries;
-
DELEGATE entries ordered by the length of the prefix,
longest first;
-
ENTITY, DOCTYPE, LINKTYPE,
NOTATION and SGML entries.
For the purpose of implying an SGML declaration, DTDDECL
entries are more specific than SGMLDECL entries.
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