dtdtree
outputs the content hierarchy tree
(in ASCII) of SGML elements defined in a DTD.
dtdtree
is invoked from the command-line as follows:
% dtdtree [options] elementname elementname ...
Any strings after, and not part of, command-line options are treated as the elements (elementname) to output trees for. If no elements are specified, than the tree(s) for the top-most element(s) defined in the DTD are printed.
The following are the list of options available:
-dtd
filenameUse filename as the SGML DTD to parse. Otherwise, read from standard in.
-help
Print a brief usage description. No other action is performed.
-level
#Set the prune level of the content hierachy tree to # Defaults to 15.
-mapfile
filenameUse filename as the file for mapping public
identifiers and external entities to system files. The default is
"map.txt
". See
Resolving External Entities for more
information.
-treefile
filenameOutput element content tree(s) to filename.
Otherwise, dtdtree
prints to standard out.
-verbose
Ouput to standard error messages of what dtdtree
is doing.
This option
is mainly for debugging purposes.
The output generated by dtdtree
is as follows:
Elements that exist at a higher (or equal) level, or if the maximum depth has been reached, are pruned. The string "..." is appended to an element if it has been pruned due to pre-existance at a higher (or equal) level. The content of the pruned element can be determined by searching for the complete tree of the element (ie. elements w/o "...").
Since the tree outputed is static, the inclusion and exclusion sets of elements are treated specially. Inclusion and exclusion elements inherited from ancestors are not propagated down to determine what elements are printed, but special markup is presented at a given element if there exists inclusion and exclusion elements from ancestors. The reason inclusion and exclusion elements are not propagated down is because of the pruning done. An element w/o "..." may be the only place of reference to see the content hierarchy of that element. However, the element may occur in multiple contents and have different ancestoral inclusion and exclusion elements applied to it.
Have I lost you? Maybe an example may help:
OPENBOOK | |_d1 | | (I): idx needbegin needend newline | | | |_abbrev | | | (Ia): idx needbegin needend newline | | | (X): needbegin needend | | | | | |_#PCDATA | | |_acro | | | | (Ia): idx needbegin needend newline | | | | (Xa): needbegin needend | | | | | | | |_#PCDATA | | | |_sub ... | | | |_super ... | | |
Ignoring the lines starting with ()'s, one gets the content hierachy
of an element as defined by the DTD without concern of where it
may occur in the overall structure. The ()'s line give additional
information regarding the element with respect to its existance
within a specific context. For example, when an acro element
occurs within openbook
/d1
/abbrev
,
along with its normal
content, it can contain idx
and newline
elements due to
inclusions from ancestors. However, it cannot contain needbegin
,
needend
regardless of its defined content since an ancestor(s)
excludes them.
needbegin
,
needend
are excluded from acro
.Explanation of ()'s keys:
(I)
(Ia)
(X)
(Xa)
dtdtree
provides the capability of resolving
external entities to system files via the
-mapfile
command-line option.
The map file, or catalog,
provides you with the capability of mapping public
identifiers to system identifiers (files) or to map entity names to
system identifiers.
dtdtree
. However, since version 1.2.0, the "map file"
format has changed to following similiar conventions of SGML catalogs
(as defined in
SGML Open Draft Technical Resolution 9401:1994).
Therefore,
the term "map file" and "catalog" are the same in the context of this
document.
A catalog contains a sequence of the following types of entries:
PUBLIC
public_id system_idThis maps public_id to system_id.
ENTITY
name system_idThis maps a general entity whose name is name to system_id.
ENTITY %
name system_idThis maps a parameter entity whose name is name to system_id.
A system_id string cannot contain any spaces. The system_id is treated as pathname of file.
Any line in a catalog file that does not follow the previously mentioned entries is ignored.
In case of duplicate entries, the first entry defined is used.
Example catalog file:
-- ISO public identifiers -- PUBLIC "ISO 8879-1986//ENTITIES General Technical//EN" iso-tech.ent PUBLIC "ISO 8879-1986//ENTITIES Publishing//EN" iso-pub.ent PUBLIC "ISO 8879-1986//ENTITIES Numeric and Special Graphic//EN" iso-num.ent PUBLIC "ISO 8879-1986//ENTITIES Greek Letters//EN" iso-grk1.ent PUBLIC "ISO 8879-1986//ENTITIES Diacritical Marks//EN" iso-dia.ent PUBLIC "ISO 8879-1986//ENTITIES Added Latin 1//EN" iso-lat1.ent PUBLIC "ISO 8879-1986//ENTITIES Greek Symbols//EN" iso-grk3.ent PUBLIC "ISO 8879-1986//ENTITIES Added Latin 2//EN" ISOlat2 PUBLIC "ISO 8879-1986//ENTITIES Added Math Symbols: Ordinary//EN" ISOamso -- HTML public identifiers and entities -- PUBLIC "-//IETF//DTD HTML//EN" html.dtd PUBLIC "ISO 8879-1986//ENTITIES Added Latin 1//EN//HTML" ISOlat1.ent ENTITY "%html-0" html-0.dtd ENTITY "%html-1" html-1.dtd
dtdtree
also supports envariables (ie. environment
variables) to aid in resolving external entities. The following
envariables are used by dtdtree
:
This is a colon (semi-colon for MSDOS users) separated list of paths for finding catalog files or system identifiers. For example, if a system identifier is not an absolute pathname, then the paths listed in P_SGML_PATH are used to find the file.
This envariable is a colon (semi-colon for MSDOS users)
separated list of catalog files to read.
The file specified by
-mapfile
is read first before any files specified by SGML_CATALOG_FILES. If
a file in the list is not an absolute path, then file is searched in
the paths listed in the P_SGML_PATH and SGML_SEARCH_PATH.
This is a colon (semi-colon for MSDOS users) separated list of paths for finding catalog files or system identifiers. This envariable serves the same function as P_SGML_PATH. If both are defined, paths listed in P_SGML_PATH are searched first before any paths in SGML_SEARCH_PATH.
The use of P_SGML_PATH is for compatibility with earlier versions
of dtdtree
. SGML_CATALOG_FILES and SGML_SEARCH_PATH
are supported for compatibility with James Clark's nsgmls(1)
.
This program is part of the perlSGML package; see <URL:http://www.oac.uci.edu/indiv/ehood/perlSGML.html>