_________________________________________________________________
                                      
                                   dtd2html
                                       
   dtd2html is a Perl program that generates an HTML document that
   documents an SGML document type definition (DTD) and allows hypertext
   navigation of an SGML DTD.
   
   Contents:
   
     * Overview
     * Usage
     * HTML File Descriptions
     * Description File
     * Quick Reference Mode
     * Updating Description File
     * Resolving External Entities
     * Availability
     * Author
       
     _________________________________________________________________
                                      
Overview

   dtd2html generates various HTML files for hypertext navigation of an
   SGML DTD. The files generated are as follows:
   
   DTD-HOME.html
          File is the home page of the HTML document. This file contains
          the basic links to start navigating through the DTD. The name
          of this file can be changed with the -homefile option. User
          text may be added to this page via the Description File.
          
   TOP-ELEM.html
          This file lists the top-most elements of the DTD, and contains
          the links to element pages describing each top-most element.
          The name of this file can be changed with the -topfile option.
          
   ALL-ELEM.html
          This file contains a list of all elements defined in the DTD.
          This page allows quick access to any individual element
          description page. The name of this file can be changed with the
          -allfile option.
          
   ENTS.html (Optional)
          File contains a list of general entities defined in the DTD.
          This file is only generated if the -ents option is specified
          during program invocation. The name of this file can be changed
          with the -entfile option.
          
   DTD-TREE.html (Optional)
          File contains the content heierachy tree(s) of the top-most
          element(s) in the DTD. This file is only generated if the -tree
          option is specified during program invocation. The name of this
          file can be changed with the -treefile option.
          
   element.html
          For each element defined in the DTD, an element description
          file is generated with a filename of the element name suffixed
          by ".html". User text may be added to this page via the
          Description File.
          
   element.attr.html
          For each element defined in the DTD, a file is generated
          describing the attributes defined for the element. User text
          may be added to this page via the Description File.
          
   element.cont.html
          For each element defined in the DTD, a file is generated
          listing the content model decleration of the element as
          declared in the DTD.
          
   Once all the files are generated, one needs only to create a link in
   the Web server being used to the DTD-HOME page.
   
   Note
          If you have a Web client that can load local files, than
          linking the DTD-HOME page to the Web server is unnecessary.
          
   More information on the content of each file is in the HTML File
   Descriptions section.
   
     _________________________________________________________________
                                      
Usage

   dtd2html is invoked from a command-line shell, with the following
   syntax:
   
   % dtd2html [options] filename
   
   filename is the SGML DTD to be parsed for generating the HTML files.
   The following is the list of options available:
   
   -allfile filename
          Set the filename for file listing all elements in the DTD to
          filename. The default name is "ALL-ELEM.html".
          
   -catalog filename
          Use filename as the file for mapping public identifiers and
          external entities to system files. If -catalog is not
          specified, "catalog" is used as the default filename. See
          Resolving External Entities for more information.
          
   -contnosort
          The base content list of the element.html page is listed as
          declared in the content model declaration. Normally, the
          elements are listed in sorted order and with no group
          delimiters, group connectors, or occurance indicators.
          
   -descfile filename
          Use filename as the source for element descriptions in the DTD.
          If this argument is not specified, no description file is used.
          See Description File for more information.
          
   -docurl URL
          Use URL for location of documentation on dtd2html. The default
          URL is "http://www.oac.uci.edu/indiv/ehood/dtd2html.html".
          
   -dtdname string
          Set the name of the DTD to string. If not specified, dtd2html
          determines the name of the DTD by its filename with the
          extension stripped off. If reading from standard input, then
          this argument should be specified. Otherwise, "Unknown" is
          used. The string " DTD" will be appended to the name of the
          DTD. If the -qref option is specified, then the string " DTD
          Quick Reference" is appended to represent the title of the
          quick reference document.
          
   -elemlist
          Generate a blank description file to standard output. See
          Description File for more information.
          
   -ents
          Generate a general entities page. The general entities types
          listed are: replaceable character data, CDATA, SDATA, and PI
          (processing instruction). Note: For large DTDs, this list may
          be quite large and provide little usefulness to the document.
          
   -entsfile filename
          Set the filename for the general entities page to filename. The
          default name is "ENTS.html".
          
   -entslist
          Generate a blank description file to standard output containing
          ONLY general entity entries. This differs from -elemlist is
          that -elemlist outputs ONLY entries for elements and
          attributes. See Description File for more information.
          
   -help
          Print out a terse description of all options available. No HTML
          files are generated and all other options are ignored when this
          option is specified.
          
   -homefile filename
          Set the filename for the HTML home page for the DTD to
          filename. The default name is "DTD-HOME.html".
          
   -keepold
          This option is only valid if -updateel is specified. This
          option tells dtd2html to preserve any old descriptions when
          updating an description file.
          
   -level #
          Set the prune level of the content hierachy tree to #. This
          option is only valid if -tree is specified.
          
   -modelwidth #
          Set the maximum output width for content model declarations to
          # for element.cont.html pages. Default value is 65.
          
   -nodocurl
          Do not insert hyperlink to dtd2html documentation in the
          DTD-HOME page.
          
   -noreport
          This option is only valid if -updateel is specified. This
          options tells dtd2html to not output a report when updating an
          description file.
          
   -outdir path
          Set destination of generated HTML files to path. Defaults to
          the current working directory.
          
   -qref
          Output a quick reference document of the DTD. The document is
          outputted to standard output (STDOUT). When this option is
          specified, only the quick reference document is generated.
          Therefore, the tree page and the -outdir options are ignored.
          See Quick Reference Mode for more information on the -qref
          option.
          
   -qrefdl
          Output a quick reference document of the DTD using the <DL>,
          definition list, HTML tag. When this option is specified, only
          the quick reference document is generated. Therefore, the tree
          page and the -outdir options are ignored. See Quick Reference
          Mode for more information. This option overrides the behavior
          of the -qref option.
          
   -qrefhtag htag
          Use htag as the header tag for the element names when the -qref
          option is specified. Defaults to '<H2>'.
          
   -reportonly
          This option is only valid if -updateel is specified. This
          options tells dtd2html to generate only a report when the
          -updateel option is specified.
          
   -topfile filename
          Set the filename for file listing the top-most elements in the
          DTD to filename. The default name is "TOP-ELEM.html".
          
   -tree
          Generate the content hierarchy of the top-most elements defined
          in the DTD.
          
   -treelink
          Create anchor in HTML pages to the tree page, even if -tree is
          not specified.
          
   -treefile filename
          Set the filename for file containing the content hierarchy
          tree(s) of the DTD to filename. The default name is
          "DTD-TREE.html". This option is only valid if -tree is
          specified.
          
   -treeonly
          Create only the tree page. This option implies -tree.
          
   -treetop string
          Set the top-most elements to string. String is a comma
          separated list of elements that dtd2html should treat as the
          top-most elements when printing the content hierarchy tree(s),
          and/or which elements get listed in the TOP-ELEM page.
          Normally, dtd2html will compute what are the top-most elements
          of the DTD. This option overrides that computation.
          
   -updateel file
          Perform an update of the description file specified by file.
          This option allows one to update an element description to
          contain any new elements/attributes that have been added to the
          DTD without affecting element descriptions already defined. See
          Updating Description File for more information.
          
   -verbose
          Print status messages to standard error on what dtd2html is
          doing. This option generates much output, and is used mainly
          for debugging purposes.
          
     _________________________________________________________________
                                      
HTML File Descriptions

   All HTML files/pages generated contain hypertext links at the end of
   the page to the DTD-HOME, TOP-ELEM, ALL-ELEM, ENTS (optional), and
   DTD-TREE (optional) pages, unless stated otherwise.
   
  DTD-HOME
  
   This page is the root of the HTML document. It contains the links to
   the other main pages as described above.
   
   One can add documentation to the home page via the Description File or
   by manually editting the file.
   
  TOP-ELEM
  
   This page contains the list of all top-most elements defined in the
   DTD. A top-most element is defined as: An element which cannot be
   contained by another element or can be only contained by itself.
   
  ALL-ELEM
  
   This page contains an alphabetic list of all elements defined in the
   DTD.
   
  ENTS
  
   This page contains an alphabetic list of of general entities defined
   in the DTD. The general entities types listed are: replaceable
   character data, CDATA, SDATA, and PI (processing instruction). Note:
   For large DTDs, this list may be quite large and provide little
   usefulness to the document. Also, entities are not handled when
   updating a description file.
   
  DTD-TREE
  
   This page contains the content hierarchy tree(s) of the top-most
   elements of the DTD. The maximum depth of the tree can be set via the
   -level command-line option.
   
   The tree shows the overall content hierarchy for an element. Content
   hierarchies of descendents will also be shown. 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 "..."). Elements pruned because
   maximum depth has been reached will not have "..." appended.
   
   Example:
   
     |__section+)
         |_(effect?, ...
         |__title, ...
         |__toc?, ...
         |__epc-fig*,
         |   |_(effect?, ...
         |   |__figure,
         |   |   |_(effect?, ...
         |   |   |__title, ...
         |   |   |__graphic+, ...
         |   |   |__assoc-text?)

   Note
          Pruning must be done to avoid a combinatorical explosion. It is
          common for DTD's to define content hierarchies of infinite
          depth. Even with a predefined maximum depth, the generated tree
          can become very large.
          
   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 inclusions and exclusions are not propagated
   down is because of the pruning done. Since an element may occur in
   multiple contexts -- and have different ancestoral inclusions and
   exclusions in effect -- an element without "..." may be the only place
   of reference to see the content hierarchy of the element.
   
   Example:
   
    D1
     |  {+} idx needbegin needend newline
     |
     |_(head,
     |   | {A+} idx needbegin needend newline
     |   |  {-} needbegin needend
     |   |
     |   |_(((#PCDATA |
     |   |____((acro |
     |   |       | {A+} idx needbegin needend newline
     |   |       | {A-} needbegin needend
     |   |       |
     |   |       |_(((#PCDATA |
     |   |       |____((super | ...
     |   |       |______sub)))*)) ...

   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 {} lines give additional
   information regarding the element with respect to its existance within
   a specific context. For example, when an ACRO element occurs within
   D1,HEAD -- along with its normal content -- it can contain IDX and
   NEWLINE elements due to inclusions from ancestors. However, it cannot
   contain NEEDBEGIN and NEEDEND regardless of its defined content since
   an ancestor(s) excludes them.
   
   Note
          Exclusions override inclusions. If an element occurs in an
          inclusion set and an exclusion set, the exclusion takes
          precedence. Therefore, in the above example, NEEDBEGIN, NEEDEND
          are excluded from ACRO.
          
   Explanation of {}'s keys:
   
   {+}
          The list of inclusion elements defined by the current element.
          Since this is part of the content model of the element, the
          inclusion subelements are printed as part of the content
          hierarchy of the current element after the base content model.
          Subelements that are inclusions will have {+} appended to the
          subelement entry.
          
   {A+}
          The list of inclusion elements due to ancestors. This is listed
          as reference to determine the content of an element within a
          given context. None of the ancestoral inclusion elements are
          printed as part of the content hierarchy of the element.
          
   {-}
          The list of exclusion elements defined by the current element.
          Since this is part of the content model of the element, any
          subelement in the content model that would be excluded will
          have {-} appended to the subelement listing.
          
   {A-}
          The list of exclusion elements due to ancestors. This is listed
          as reference to determine the content of an element within a
          given context. None of the ancestoral exclusion elements have
          any effect on the printing of the content hierarchy of the
          current element.
          
  element
  
   The element page describes the content of element. The element page is
   divided into the following sections:
   
     * Element description (optional, see Description File).
     * Links to subelements broken into three parts:
          + Base content
          + Inclusions (if defined)
          + Exclusions (if defined)
     * Links to element's attribute and content declaration pages.
     * Tag minimization (if defined).
     * Links to all possible parent elements.
     * Links to main pages as described above. However, the link to the
       DTD-TREE goes to the complete element entry in the tree.
       
  element.attr
  
   The element.attr page describes the attributes of element. The
   element.attr page is divided into the following sections:
   
     * Attribute description (optional, see Description File).
     * List of attributes with possible values and default value.
     * Link back to element page.
       
   This page is not created if no attributes are defined for element.
   
  element.cont
  
   The element.cont page gives the element's content model decleration as
   defined in the DTD. The element.cont page is divided into the
   following sections:
   
     * Base content decleration.
     * Inclusion content decleration (if defined).
     * Exclusion content decleration (if defined).
     * Link back to element page.
       
   The content models are reformatted to allow better readability. The
   maximum width to use when reformating is set by the -modelwidth
   option. Each element listed in the content model is a hyperlink to
   that element's page.
   
   Here's an example of how dtd2html formats content model declarations:
   
    (((#PCDATA|
       ((acro|book|emph|location|not|parm|term|var))|
       ((super|sub))|
       ((link|xref))|
       ((computer|cursor|display|keycap|softkey|user))|
       ((footnote|ineqn|ingraphic|fillin))|
       ((nobreak)))*))

   This page is not created if element is defined with empty content.
   
     _________________________________________________________________
                                      
Description File

   dtd2html supports the ability to add documentation to the HTML files
   generated from a DTD through the -descfile option. Documentation can
   be added to the element pages, the attribute pages, and/or ents page.
   
  Basic Syntax
  
   The basic syntax of the description file is as follows:
   
    <?DTD2HTML identifier>
    <P>
    Description of identifier here.
    </P>
    <?DTD2HTML identifier>
    <P>
    Description of identifier here.
    </P>
    ...

   The line <?DTD2HTML identifier> signifies the beginning of a
   description entry for identifier. All text up to the next <?DTD2HTML
   ...> instruction or end-of-file is used as the identifier description.
   
   The identifier can be one of the following formats:
   
   element
          An element name in the DTD. The following description text will
          go at the top of the element's page.
          
   element*
          An element in the DTD followed by a `*'. The following
          description text will go at the top of the element's attribute
          page.
          
   element*attribute
          An element in the DTD followed by a `*' which is followed by an
          attribute name of the element. The following description text
          will go below the attribute heading of the element's attribute
          page.
          
   element+
          An element in the DTD followed by a '+'. The following
          description text goes after each elements listed in ALL-ELEM
          and in element pages. Due to the context that the description
          text will appear (ie. inside a <LI> element), it is best to
          keep the description to a single sentence.
          
   *attribute
          A `*' followed by an attribute name. The following description
          text will go to any attribute named attribute, unless a
          specific description is given to the attribute via an
          element*attribute. This identifier allows to add descriptions
          to commonly shared attributes in one locale.
          
   entity&
          A general entity followed by a '&'. The following description
          text will go after each entity listed in the ENTS page. Due to
          the context that the description text will appear (ie. inside a
          <LI> element), it is best to keep the description to a single
          sentence.
          
   identifier,identifier,...
          A sequence of identifiers separated by commas, `,'. This allows
          a description to be shared among muliple identifiers. Note:
          there should be NO whitespace between the identifiers and the
          commas.
          
   If the special element, -HOME-, is specified in the description file,
   then its description text will be put on the DTD-HOME page.
   
  Special Instructions
  
   dtd2html provides special instructions that may be used in a
   description file to control how dtd2html processes the file.
   
   Special instructions follow a similiar syntax as descriptive
   instructions:

    <?DTD2HTML #instruction argument>

   The following special instructions are defined:
   
   #include argument
          The include directive tells dtd2html to treat the argument as a
          filename to read that contains description entries. Example:
          
    <?DTD2HTML #include ents.dsc>

          The example instructs dtd2html to open a file called ents.dsc
          and read it for description entries.
          
  Comments
  
   SGML comments are also supported in the description file. Comments are
   skipped by dtd2html. The syntax for a comment is the following:
   
    <!-- This is a comment -->

   WARNING
          dtd2html can only handle a comment that spans a single line (to
          make the parsing simple). Therefore, the following will cause
          dtd2html to add the comment text beyond the first line of the
          comment to an indentifier's description:
          
    <!-- This is a comment
         that spans more than one line.
      -->

          If you want to put line breaks in the description file without
          them being applied to an indentifier's description, then use
          the SGML short comment: <!>.
          
  Example
  
<!-- Include external descriptions -->
<!>
<?DTD2HTML #include ents.dsc>
<!>
<!-- A short description -->
<!>
<?DTD2HTML a+ >
Anchor; source and/or destination of a link
<!>
<!-- A shared description -->
<!>
<?DTD2HTML h1,h2,h3,h4,h5,h6 >
<p>
The six heading elements,
<H1> through <H6>, denote section headings.
Although the order and occurrence of headings is not constrained by
the HTML DTD, documents should not skip levels (for example, from H1
to H3), as converting such documents to other representations is
often problematic.
</p>
<!>
<!-- Element and attribute descriptions -->
<!>
<?DTD2HTML a >
<p>
The &lt;A&gt; element indicates a hyperlink anchor.
At least one of the NAME and HREF attributes should be present.
</p>
<?DTD2HTML a* >
<?DTD2HTML a*href >
<p>
Gives the URI of the head anchor of a hyperlink.
</p>
<?DTD2HTML a*methods >
<p>
Specifies methods to be used in accessing the
destination, as a whitespace-separated list of names.
The set of applicable names is a function of the scheme
of the URI in the HREF attribute. For similar reasons as
for the <a href="title.html">TITLE</a>
attribute, it may be useful to include the
information in advance in the link. For example, the
HTML user agent may chose a different rendering as a
function of the methods allowed; for example, something
that is searchable may get a different icon.
</p>

  Description File Notes
  
     * dtd2html ignores element descriptions that are empty or contain
       only the <P> tag.
     * If duplicate descriptions exist, the first one defined is used (In
       versions prior to 1.3.0, it was the last description defined that
       was used).
     * To get started with a description file for a DTD, you can use the
       -elemlist option to dtd2html to generate a file with all elements
       and attributes defined in the DTD with empty descriptions.
     * To get a list of general entities, you can use the -entslist
       option to dtd2html to generate a file with general entities
       defined in the DTD with empty descriptions.
       
     _________________________________________________________________
                                      
Quick Reference Mode

   dtd2html supports the ability to generate a quick reference document
   of a DTD with the -qref option. The document generated is sent to
   standard output (STDOUT). Therefore, one should redirect STDOUT to a
   file. Example:
   
    % dtd2html -qref html.dtd > htmlqref.html

   No other output/files are generated while in quick reference mode.
   
   The format of the quick reference document is as follows:
   
     * The title is determined by the -dtdname option (or the filename of
       the DTD if the option is not specified).
     * Each element is listed in an <H2> tag (or the tag specified by the
       -qrefhtag option) wrapped with the '<>' characters.
     * Any element description text follows the element heading if
       defined in a description file.
     * All elements are listed in alphabetical order.
     * Each element in the <H2> tag is wrapped with the <A
       NAME="element"> tag so one may cross-reference the element if
       desired. Example:

    <H2><A NAME="body">&lt;body&gt;</A></H2>.

  Defintion List, <DL>, Format
  
   An alternative format for the quick reference document may be
   generated with the -qrefdl command-line option. The format of the
   document shares the same properties as those of the -qref option, with
   the following exceptions:
   
     * All elements are listed in a <DL>, definition list.
     * Each element is listed in the <DT> section of <DL>.
     * Element descriptions are placed in the <DD> section of the <DL>.
       
   Each element is still wrapped in a <A NAME> statement to allow
   cross-referencing.
   
  Quick Reference Notes
  
     * -qrefdl takes precedence over -qref if both are specified on the
       command-line.
       
  Quick Reference Tips
  
     * Keep element descriptions as brief as possible. The quick
       reference document may get quite large for large DTDs. Care must
       also be given if using the -qrefdl option; less HTML markup is
       available while in a <DL>.
     * Keep a separate description file just for the quick reference.
       Usually, the description file used in the normal dtd2html output
       would be inappropriate for a quick reference.
     * The -HOME- element description identifier may be used to place
       text before the list of elements. One could add a link to the
       DTD-HOME page that is generated by dtd2html when the -qref option
       is not used.
       
     _________________________________________________________________
                                      
Updating Description File

   As a DTD changes, one can automatically update the element description
   file for the DTD to reflect the changes via the -updateel command line
   option. The new updated description file is sent to standard output
   (STDOUT). Therefore, one should redirect STDOUT to a file. Example:
   
    % dtd2html -updateel html.desc html.dtd > html-new.desc

   When updating a description file, a report is prepended to the new
   description file. The report is contained in SGML comment declaration
   statements. Here's an example of what the report looks like:
   
<!-- Element Description File Update                                      -->
<!-- Source File:  sgm/html.desc                                          -->
<!-- Source DTD:  sgm/html.2.0/html.dtd                                   -->
<!-- Deleting Old?  Yes                                                   -->
<!-- Date:  Mon Jun 27 00:25:41 EDT 1994                                  -->
<!-- New identifiers:                                                     -->
<!--    br, dl*, dl*compact, form, form*, form*action, form*enctype,      -->
<!--    form*method, img*ismap, input, input*, input*align,               -->
<!--    input*checked, input*maxlength, input*name, input*size,           -->
<!--    input*src, input*type, input*value, option, option*,              -->
<!--    option*selected, option*value, select, select*,                   -->
<!--    select*multiple, select*name, select*size, strike, textarea,      -->
<!--    textarea*, textarea*cols, textarea*name, textarea*rows            -->
<!-- Old identifiers:                                                     -->
<!--    dir*, dir*compact, key, link*name, menu*, menu*compact, ol*,      -->
<!--    ol*compact, u, ul*, ul*compact                                    -->
<!--                                                                      -->

  Updating Notes
  
     * Entity descriptions are NOT checked, and are excluded from the
       output. Only elements and attributes are processed.
     * If the description file processed contains "#include"
       instructions, these instructions are not preserved in the output.
       The output is a merging of all description entries processed.
     * If "#include" instruction are used, it may be best to use the
       -reportonly option. Therefore, you can determine what has changed
       and update the description file(s) manually.
     * The report will specify any new identifiers that were created, and
       any old identifier no longer applicable to the DTD.
     * By default, any old identifiers are removed in the new element
       description file. This can be overriden by the -keepold option.
       The report will state if old identifiers are deleted or not.
     * ALL non-deleted identifiers keep all the description text
       specified in the source (original) description file.
     * If you desire no report, use the -noreport option.
     * If all you desire is to see what changes exist without creating a
       new description file, then use the -reportonly option. This option
       will only cause the report to be generated. This may be used to
       help keep track of changes in a DTD.
     * Any user entered comments in the source element description file
       are lost in the update.
       
     _________________________________________________________________
                                      
Resolving External Entities

   Defining the mapping between external entities to system files may be
   done via the -catalog command-line option. The catalog provides you
   with the capability of mapping public identifiers to system
   identifiers (files) or to map entity names to system identifiers.
   
   Catalog Syntax
   
   The syntax of a catalog is a subset of SGML catalogs (as defined in
   SGML Open Draft Technical Resolution 9401:1994).
   
   A catalog contains a sequence of the following types of entries:
   
   PUBLIC public_id system_id
          This maps public_id to system_id.
          
   ENTITY name system_id
          This maps a general entity whose name is name to system_id.
          
   ENTITY %name system_id
          This maps a parameter entity whose name is name to system_id.
          
   Syntax Notes
   
     * 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

   Environment Variables
   
   The following envariables (ie. environment variables) are supported:
   
   P_SGML_PATH
          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.
          
   SGML_CATALOG_FILES
          This envariable is a colon (semi-colon for MSDOS users)
          separated list of catalog files to read. 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.
          
   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.
   SGML_CATALOG_FILES and SGML_SEARCH_PATH are supported for
   compatibility with James Clark's nsgmls(1).
   
   Note
          When searching for a file via the P_SGML_PATH and/or
          SGML_SEARCH_PATH, if the file is not found in any of the paths,
          then the current working directory is searched.
          
   Note
          The file specified by -catalog is read first before any files
          specified by SGML_CATALOG_FILES.
          
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Availability

   This program is part of the perlSGML package; see
   <URL:http://www.oac.uci.edu/indiv/ehood/perlSGML.html>
   
     _________________________________________________________________
                                      
Author

   
    Earl Hood <ehood@medusa.acs.uci.edu>
    
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