Pod::Simple::Subclassing(category27-allgemeinwissen.html) - phpMan

Pod::Simple::SubclassiUser)Contributed Perl DocumenPod::Simple::Subclassing(3)

NAME
       Pod::Simple::Subclassing -- write a formatter as a Pod::Simple subclass
SYNOPSIS
         package Pod::SomeFormatter;
         use Pod::Simple;
         @ISA = qw(Pod::Simple);
         $VERSION = '1.01';
         use strict;
         sub _handle_element_start {
               my($parser, $element_name, $attr_hash_r) = @_;
               ...
         }
         sub _handle_element_end {
               my($parser, $element_name, $attr_hash_r) = @_;
               # NOTE: $attr_hash_r is only present when $element_name is "over" or "begin"
               # The remaining code excerpts will mostly ignore this $attr_hash_r, as it is
               # mostly useless. It is documented where "over-*" and "begin" events are
               # documented.
               ...
         }
         sub _handle_text {
               my($parser, $text) = @_;
               ...
         }
         1;
DESCRIPTION
       This document is about using Pod::Simple to write a Pod processor,
       generally a Pod formatter. If you just want to know about using an
       existing Pod formatter, instead see its documentation and see also the
       docs in Pod::Simple.
       The zeroeth step in writing a Pod formatter is to make sure that there
       isn't already a decent one in CPAN. See <http://search.cpan.org/>;, and
       run a search on the name of the format you want to render to. Also
       consider joining the Pod People list
       <http://lists.perl.org/showlist.cgi?name=pod-people>; and asking whether
       anyone has a formatter for that format -- maybe someone cobbled one
       together but just hasn't released it.
       The first step in writing a Pod processor is to read perlpodspec, which
       contains notes information on writing a Pod parser (which has been
       largely taken care of by Pod::Simple), but also a lot of requirements
       and recommendations for writing a formatter.
       The second step is to actually learn the format you're planning to
       format to -- or at least as much as you need to know to represent Pod,
       which probably isn't much.
       The third step is to pick which of Pod::Simple's interfaces you want to
       use -- the basic interface via Pod::Simple or Pod::Simple::Methody is
       event-based, sort of like HTML::Parser's interface, or sort of like
       XML::Parser's "Handlers" interface), but Pod::Simple::PullParser
       provides a token-stream interface, sort of like HTML::TokeParser's
       interface; Pod::Simple::SimpleTree provides a simple tree interface,
       rather like XML::Parser's "Tree" interface. Users familiar with XML-
       handling will find one of these styles relatively familiar; but if you
       would be even more at home with XML, there are classes that produce an
       XML representation of the Pod stream, notably
       Pod::Simple::XMLOutStream; you can feed the output of such a class to
       whatever XML parsing system you are most at home with.
       The last step is to write your code based on how the events (or tokens,
       or tree-nodes, or the XML, or however you're parsing) will map to
       constructs in the output format. Also sure to consider how to escape
       text nodes containing arbitrary text, and also what to do with text
       nodes that represent preformatted text (from verbatim sections).
Events
       TODO intro... mention that events are supplied for implicits, like for
       missing >'s
       In the following section, we use XML to represent the event structure
       associated with a particular construct.  That is, TODO
       "$parser->_handle_element_start( element_name, attr_hashref )"
       "$parser->_handle_element_end( element_name  )"
       "$parser->_handle_text(  text_string  )"
       TODO describe
       events with an element_name of Document
           Parsing a document produces this event structure:
             <Document start_line="543">
                   ...all events...
             </Document>
           The value of the start_line attribute will be the line number of
           the first Pod directive in the document.
           If there is no Pod in the given document, then the event structure
           will be this:
             <Document contentless="1" start_line="543">
             </Document>
           In that case, the value of the start_line attribute will not be
           meaningful; under current implementations, it will probably be the
           line number of the last line in the file.
       events with an element_name of Para
           Parsing a plain (non-verbatim, non-directive, non-data) paragraph
           in a Pod document produces this event structure:
                   <Para start_line="543">
                     ...all events in this paragraph...
                   </Para>
           The value of the start_line attribute will be the line number of
           the start of the paragraph.
           For example, parsing this paragraph of Pod:
             The value of the I<start_line> attribute will be the
             line number of the start of the paragraph.
           produces this event structure:
                   <Para start_line="129">
                     The value of the
                     <I>
                           start_line
                     </I>
                      attribute will be the line number of the first Pod directive
                     in the document.
                   </Para>
       events with an element_name of B, C, F, or I.
           Parsing a B<...> formatting code (or of course any of its
           semantically identical syntactic variants B<< ... >>, or
           B<<<< ... >>>>, etc.)  produces this event structure:
                     <B>
                           ...stuff...
                     </B>
           Currently, there are no attributes conveyed.
           Parsing C, F, or I codes produce the same structure, with only a
           different element name.
           If your parser object has been set to accept other formatting
           codes, then they will be presented like these B/C/F/I codes --
           i.e., without any attributes.
       events with an element_name of S
           Normally, parsing an S<...> sequence produces this event structure,
           just as if it were a B/C/F/I code:
                     <S>
                           ...stuff...
                     </S>
           However, Pod::Simple (and presumably all derived parsers) offers
           the "nbsp_for_S" option which, if enabled, will suppress all S
           events, and instead change all spaces in the content to non-
           breaking spaces. This is intended for formatters that output to a
           format that has no code that means the same as S<...>, but which
           has a code/character that means non-breaking space.
       events with an element_name of X
           Normally, parsing an X<...> sequence produces this event structure,
           just as if it were a B/C/F/I code:
                     <X>
                           ...stuff...
                     </X>
           However, Pod::Simple (and presumably all derived parsers) offers
           the "nix_X_codes" option which, if enabled, will suppress all X
           events and ignore their content.  For formatters/processors that
           don't use X events, this is presumably quite useful.
       events with an element_name of L
           Because the L<...> is the most complex construct in the language,
           it should not surprise you that the events it generates are the
           most complex in the language. Most of complexity is hidden away in
           the attribute values, so for those of you writing a Pod formatter
           that produces a non-hypertextual format, you can just ignore the
           attributes and treat an L event structure like a formatting element
           that (presumably) doesn't actually produce a change in formatting.
           That is, the content of the L event structure (as opposed to its
           attributes) is always what text should be displayed.
           There are, at first glance, three kinds of L links: URL, man, and
           pod.
           When a L<some_url> code is parsed, it produces this event
           structure:
             <L content-implicit="yes" raw="that_url" to="that_url" type="url">
                   that_url
             </L>
           The "type="url"" attribute is always specified for this type of L
           code.
           For example, this Pod source:
             L<http://www.perl.com/CPAN/authors/>;
           produces this event structure:
             <L content-implicit="yes" raw="http://www.perl.com/CPAN/authors/" to="http://www.perl.com/CPAN/authors/" type="url">
                   http://www.perl.com/CPAN/authors/
             </L>
           When a L<manpage(section)> code is parsed (and these are fairly
           rare and not terribly useful), it produces this event structure:
             <L content-implicit="yes" raw="manpage(section)" to="manpage(section)" type="man">
                   manpage(section)
             </L>
           The "type="man"" attribute is always specified for this type of L
           code.
           For example, this Pod source:
             L<crontab(5)>
           produces this event structure:
             <L content-implicit="yes" raw="crontab(5)" to="crontab(5)" type="man">
                   crontab(5)
             </L>
           In the rare cases where a man page link has a specified, that text
           appears in a section attribute. For example, this Pod source:
             L<crontab(5)/"ENVIRONMENT">
           will produce this event structure:
             <L content-implicit="yes" raw="crontab(5)/&quot;ENVIRONMENT&quot;" section="ENVIRONMENT" to="crontab(5)" type="man">
                   "ENVIRONMENT" in crontab(5)
             </L>
           In the rare case where the Pod document has code like
           L<sometext|manpage(section)>, then the sometext will appear as the
           content of the element, the manpage(section) text will appear only
           as the value of the to attribute, and there will be no
           "content-implicit="yes"" attribute (whose presence means that the
           Pod parser had to infer what text should appear as the link text --
           as opposed to cases where that attribute is absent, which means
           that the Pod parser did not have to infer the link text, because
           that L code explicitly specified some link text.)
           For example, this Pod source:
             L<hell itself!|crontab(5)>
           will produce this event structure:
             <L raw="hell itself!|crontab(5)" to="crontab(5)" type="man">
                   hell itself!
             </L>
           The last type of L structure is for links to/within Pod documents.
           It is the most complex because it can have a to attribute, or a
           section attribute, or both. The "type="pod"" attribute is always
           specified for this type of L code.
           In the most common case, the simple case of a L<podpage> code
           produces this event structure:
             <L content-implicit="yes" raw="podpage" to="podpage" type="pod">
                   podpage
             </L>
           For example, this Pod source:
             L<Net::Ping>
           produces this event structure:
             <L content-implicit="yes" raw="Net::Ping" to="Net::Ping" type="pod">
                   Net::Ping
             </L>
           In cases where there is link-text explicitly specified, it is to be
           found in the content of the element (and not the attributes), just
           as with the L<sometext|manpage(section)> case discussed above.  For
           example, this Pod source:
             L<Perl Error Messages|perldiag>
           produces this event structure:
             <L raw="Perl Error Messages|perldiag" to="perldiag" type="pod">
                   Perl Error Messages
             </L>
           In cases of links to a section in the current Pod document, there
           is a section attribute instead of a to attribute.  For example,
           this Pod source:
             L</"Member Data">
           produces this event structure:
             <L content-implicit="yes" raw="/&quot;Member Data&quot;" section="Member Data" type="pod">
                   "Member Data"
             </L>
           As another example, this Pod source:
             L<the various attributes|/"Member Data">
           produces this event structure:
             <L raw="the various attributes|/&quot;Member Data&quot;" section="Member Data" type="pod">
                   the various attributes
             </L>
           In cases of links to a section in a different Pod document, there
           are both a section attribute and a to attribute.  For example, this
           Pod source:
             L<perlsyn/"Basic BLOCKs and Switch Statements">
           produces this event structure:
             <L content-implicit="yes" raw="perlsyn/&quot;Basic BLOCKs and Switch Statements&quot;" section="Basic BLOCKs and Switch Statements" to="perlsyn" type="pod">
                   "Basic BLOCKs and Switch Statements" in perlsyn
             </L>
           As another example, this Pod source:
             L<SWITCH statements|perlsyn/"Basic BLOCKs and Switch Statements">
           produces this event structure:
             <L raw="SWITCH statements|perlsyn/&quot;Basic BLOCKs and Switch Statements&quot;" section="Basic BLOCKs and Switch Statements" to="perlsyn" type="pod">
                   SWITCH statements
             </L>
           Incidentally, note that we do not distinguish between these
           syntaxes:
             L</"Member Data">
             L<"Member Data">
             L</Member Data>
             L<Member Data>    [deprecated syntax]
           That is, they all produce the same event structure (for the most
           part), namely:
             <L content-implicit="yes" raw="$depends_on_syntax" section="Member Data" type="pod">
                   &#34;Member Data&#34;
             </L>
           The raw attribute depends on what the raw content of the "L<>" is,
           so that is why the event structure is the same "for the most part".
           If you have not guessed it yet, the raw attribute contains the raw,
           original, unescaped content of the "L<>" formatting code. In
           addition to the examples above, take notice of the following event
           structure produced by the following "L<>" formatting code.
             L<click B<here>|page/About the C<-M> switch>
             <L raw="click B<here>|page/About the C<-M> switch" section="About the -M switch" to="page" type="pod">
                   click B<here>
             </L>
           Specifically, notice that the formatting codes are present and
           unescaped in raw.
           There is a known bug in the raw attribute where any surrounding
           whitespace is condensed into a single ' '. For example, given L<
           link>, raw will be " link".
       events with an element_name of E or Z
           While there are Pod codes E<...> and Z<>, these do not produce any
           E or Z events -- that is, there are no such events as E or Z.
       events with an element_name of Verbatim
           When a Pod verbatim paragraph (AKA "codeblock") is parsed, it
           produces this event structure:
             <Verbatim start_line="543" xml:space="preserve">
                   ...text...
             </Verbatim>
           The value of the start_line attribute will be the line number of
           the first line of this verbatim block.  The xml:space attribute is
           always present, and always has the value "preserve".
           The text content will have tabs already expanded.
       events with an element_name of head1 .. head4
           When a "=head1 ..." directive is parsed, it produces this event
           structure:
             <head1>
                   ...stuff...
             </head1>
           For example, a directive consisting of this:
             =head1 Options to C<new> et al.
           will produce this event structure:
             <head1 start_line="543">
                   Options to
                   <C>
                     new
                   </C>
                    et al.
             </head1>
           "=head2" thru "=head4" directives are the same, except for the
           element names in the event structure.
       events with an element_name of encoding
           In the default case, the events corresponding to "=encoding"
           directives are not emitted. They are emitted if
           "keep_encoding_directive" is true.  In that case they produce event
           structures like "events with an element_name of head1 .. head4"
           above.
       events with an element_name of over-bullet
           When an "=over ... =back" block is parsed where the items are a
           bulleted list, it will produce this event structure:
             <over-bullet indent="4" start_line="543">
                   <item-bullet start_line="545">
                     ...Stuff...
                   </item-bullet>
                   ...more item-bullets...
             </over-bullet fake-closer="1">
           The attribute fake-closer is only present if it is a true value; it
           is not present if it is a false value. It is shown in the above
           example to illustrate where the attribute is (in the closing tag).
           It signifies that the "=over" did not have a matching "=back", and
           thus Pod::Simple had to create a fake closer.
           For example, this Pod source:
             =over
             =item *
             Something
             =back
           Would produce an event structure that does not have the fake-closer
           attribute, whereas this Pod source:
             =over
             =item *
             Gasp! An unclosed =over block!
           would. The rest of the over-* examples will not demonstrate this
           attribute, but they all can have it. See Pod::Checker's source for
           an example of this attribute being used.
           The value of the indent attribute is whatever value is after the
           "=over" directive, as in "=over 8".  If no such value is specified
           in the directive, then the indent attribute has the value "4".
           For example, this Pod source:
             =over
             =item *
             Stuff
             =item *
             Bar I<baz>!
             =back
           produces this event structure:
             <over-bullet indent="4" start_line="10">
                   <item-bullet start_line="12">
                     Stuff
                   </item-bullet>
                   <item-bullet start_line="14">
                     Bar <I>baz</I>!
                   </item-bullet>
             </over-bullet>
       events with an element_name of over-number
           When an "=over ... =back" block is parsed where the items are a
           numbered list, it will produce this event structure:
             <over-number indent="4" start_line="543">
                   <item-number number="1" start_line="545">
                     ...Stuff...
                   </item-number>
                   ...more item-number...
             </over-bullet>
           This is like the "over-bullet" event structure; but note that the
           contents are "item-number" instead of "item-bullet", and note that
           they will have a "number" attribute, which some
           formatters/processors may ignore (since, for example, there's no
           need for it in HTML when producing an "<UL><LI>...</LI>...</UL>"
           structure), but which any processor may use.
           Note that the values for the number attributes of "item-number"
           elements in a given "over-number" area will start at 1 and go up by
           one each time.  If the Pod source doesn't follow that order (even
           though it really should should!), whatever numbers it has will be
           ignored (with the correct values being put in the number
           attributes), and an error message might be issued to the user.
       events with an element_name of over-text
           These events are somewhat unlike the other over-* structures, as
           far as what their contents are.  When an "=over ... =back" block is
           parsed where the items are a list of text "subheadings", it will
           produce this event structure:
             <over-text indent="4" start_line="543">
                   <item-text>
                     ...stuff...
                   </item-text>
                   ...stuff (generally Para or Verbatim elements)...
                   <item-text>
                   ...more item-text and/or stuff...
             </over-text>
           The indent and fake-closer attributes are as with the other over-*
           events.
           For example, this Pod source:
             =over
             =item Foo
             Stuff
             =item Bar I<baz>!
             Quux
             =back
           produces this event structure:
             <over-text indent="4" start_line="20">
                   <item-text start_line="22">
                     Foo
                   </item-text>
                   <Para start_line="24">
                     Stuff
                   </Para>
                   <item-text start_line="26">
                     Bar
                           <I>
                             baz
                           </I>
                     !
                   </item-text>
                   <Para start_line="28">
                     Quux
                   </Para>
             </over-text>
       events with an element_name of over-block
           These events are somewhat unlike the other over-* structures, as
           far as what their contents are.  When an "=over ... =back" block is
           parsed where there are no items, it will produce this event
           structure:
             <over-block indent="4" start_line="543">
                   ...stuff (generally Para or Verbatim elements)...
             </over-block>
           The indent and fake-closer attributes are as with the other over-*
           events.
           For example, this Pod source:
             =over
             For cutting off our trade with all parts of the world
             For transporting us beyond seas to be tried for pretended offenses
             He is at this time transporting large armies of foreign mercenaries to
             complete the works of death, desolation and tyranny, already begun with
             circumstances of cruelty and perfidy scarcely paralleled in the most
             barbarous ages, and totally unworthy the head of a civilized nation.
             =back
           will produce this event structure:
             <over-block indent="4" start_line="2">
                   <Para start_line="4">
                     For cutting off our trade with all parts of the world
                   </Para>
                   <Para start_line="6">
                     For transporting us beyond seas to be tried for pretended offenses
                   </Para>
                   <Para start_line="8">
                     He is at this time transporting large armies of [...more text...]
                   </Para>
             </over-block>
       events with an element_name of over-empty
           Note: These events are only triggered if "parse_empty_lists()" is
           set to a true value.
           These events are somewhat unlike the other over-* structures, as
           far as what their contents are.  When an "=over ... =back" block is
           parsed where there is no content, it will produce this event
           structure:
             <over-empty indent="4" start_line="543">
             </over-empty>
           The indent and fake-closer attributes are as with the other over-*
           events.
           For example, this Pod source:
             =over
             =over
             =back
             =back
           will produce this event structure:
             <over-block indent="4" start_line="1">
                   <over-empty indent="4" start_line="3">
                   </over-empty>
             </over-block>
           Note that the outer "=over" is a block because it has no "=item"s
           but still has content: the inner "=over". The inner "=over", in
           turn, is completely empty, and is treated as such.
       events with an element_name of item-bullet
           See "events with an element_name of over-bullet", above.
       events with an element_name of item-number
           See "events with an element_name of over-number", above.
       events with an element_name of item-text
           See "events with an element_name of over-text", above.
       events with an element_name of for
           TODO...
       events with an element_name of Data
           TODO...
More Pod::Simple Methods
       Pod::Simple provides a lot of methods that aren't generally interesting
       to the end user of an existing Pod formatter, but some of which you
       might find useful in writing a Pod formatter. They are listed below.
       The first several methods (the accept_* methods) are for declaring the
       capabilities of your parser, notably what "=for targetname" sections
       it's interested in, what extra N<...> codes it accepts beyond the ones
       described in the perlpod.
       "$parser->accept_targets( SOMEVALUE )"
           As the parser sees sections like:
                   =for html  <img src="fig1.jpg">
           or
                   =begin html
                     <img src="fig1.jpg">
                   =end html
           ...the parser will ignore these sections unless your subclass has
           specified that it wants to see sections targeted to "html" (or
           whatever the formatter name is).
           If you want to process all sections, even if they're not targeted
           for you, call this before you start parsing:
             $parser->accept_targets('*');
       "$parser->accept_targets_as_text(  SOMEVALUE  )"
           This is like accept_targets, except that it specifies also that the
           content of sections for this target should be treated as Pod text
           even if the target name in "=for targetname" doesn't start with a
           ":".
           At time of writing, I don't think you'll need to use this.
       "$parser->accept_codes( Codename, Codename...  )"
           This tells the parser that you accept additional formatting codes,
           beyond just the standard ones (I B C L F S X, plus the two weird
           ones you don't actually see in the parse tree, Z and E). For
           example, to also accept codes "N", "R", and "W":
                   $parser->accept_codes( qw( N R W ) );
           TODO: document how this interacts with =extend, and long element
           names
       "$parser->accept_directive_as_data( directive_name )"
       "$parser->accept_directive_as_verbatim( directive_name )"
       "$parser->accept_directive_as_processed( directive_name )"
           In the unlikely situation that you need to tell the parser that you
           will accept additional directives ("=foo" things), you need to
           first set the parser to treat its content as data (i.e., not really
           processed at all), or as verbatim (mostly just expanding tabs), or
           as processed text (parsing formatting codes like B<...>).
           For example, to accept a new directive "=method", you'd presumably
           use:
                   $parser->accept_directive_as_processed("method");
           so that you could have Pod lines like:
                   =method I<$whatever> thing B<um>
           Making up your own directives breaks compatibility with other Pod
           formatters, in a way that using "=for target ..." lines doesn't;
           however, you may find this useful if you're making a Pod superset
           format where you don't need to worry about compatibility.
       "$parser->nbsp_for_S( BOOLEAN );"
           Setting this attribute to a true value (and by default it is false)
           will turn "S<...>" sequences into sequences of words separated by
           "\xA0" (non-breaking space) characters. For example, it will take
           this:
                   I like S<Dutch apple pie>, don't you?
           and treat it as if it were:
                   I like DutchE<nbsp>appleE<nbsp>pie, don't you?
           This is handy for output formats that don't have anything quite
           like an "S<...>" code, but which do have a code for non-breaking
           space.
           There is currently no method for going the other way; but I can
           probably provide one upon request.
       "$parser->version_report()"
           This returns a string reporting the $VERSION value from your module
           (and its classname) as well as the $VERSION value of Pod::Simple.
           Note that perlpodspec requires output formats (wherever possible)
           to note this detail in a comment in the output format.  For
           example, for some kind of SGML output format:
                   print OUT "<!-- \n", $parser->version_report, "\n -->";
       "$parser->pod_para_count()"
           This returns the count of Pod paragraphs seen so far.
       "$parser->line_count()"
           This is the current line number being parsed. But you might find
           the "line_number" event attribute more accurate, when it is
           present.
       "$parser->nix_X_codes(  SOMEVALUE  )"
           This attribute, when set to a true value (and it is false by
           default) ignores any "X<...>" sequences in the document being
           parsed.  Many formats don't actually use the content of these
           codes, so have no reason to process them.
       "$parser->keep_encoding_directive(  SOMEVALUE  )"
           This attribute, when set to a true value (it is false by default)
           will keep "=encoding" and its content in the event structure. Most
           formats don't actually need to process the content of an
           "=encoding" directive, even when this directive sets the encoding
           and the processor makes use of the encoding information. Indeed, it
           is possible to know the encoding without processing the directive
           content.
       "$parser->merge_text(  SOMEVALUE  )"
           This attribute, when set to a true value (and it is false by
           default) makes sure that only one event (or token, or node) will be
           created for any single contiguous sequence of text.  For example,
           consider this somewhat contrived example:
                   I just LOVE Z<>hotE<32>apple pie!
           When that is parsed and events are about to be called on it, it may
           actually seem to be four different text events, one right after
           another: one event for "I just LOVE ", one for "hot", one for " ",
           and one for "apple pie!". But if you have merge_text on, then
           you're guaranteed that it will be fired as one text event:  "I just
           LOVE hot apple pie!".
       "$parser->code_handler(  CODE_REF  )"
           This specifies code that should be called when a code line is seen
           (i.e., a line outside of the Pod).  Normally this is undef, meaning
           that no code should be called.  If you provide a routine, it should
           start out like this:
                   sub get_code_line {  # or whatever you'll call it
                     my($line, $line_number, $parser) = @_;
                     ...
                   }
           Note, however, that sometimes the Pod events aren't processed in
           exactly the same order as the code lines are -- i.e., if you have a
           file with Pod, then code, then more Pod, sometimes the code will be
           processed (via whatever you have code_handler call) before the all
           of the preceding Pod has been processed.
       "$parser->cut_handler(  CODE_REF  )"
           This is just like the code_handler attribute, except that it's for
           "=cut" lines, not code lines. The same caveats apply. "=cut" lines
           are unlikely to be interesting, but this is included for
           completeness.
       "$parser->pod_handler(  CODE_REF  )"
           This is just like the code_handler attribute, except that it's for
           "=pod" lines, not code lines. The same caveats apply. "=pod" lines
           are unlikely to be interesting, but this is included for
           completeness.
       "$parser->whiteline_handler(  CODE_REF  )"
           This is just like the code_handler attribute, except that it's for
           lines that are seemingly blank but have whitespace (" " and/or
           "\t") on them, not code lines. The same caveats apply. These lines
           are unlikely to be interesting, but this is included for
           completeness.
       "$parser->whine( linenumber, complaint string )"
           This notes a problem in the Pod, which will be reported to in the
           "Pod Errors" section of the document and/or send to STDERR,
           depending on the values of the attributes "no_whining",
           "no_errata_section", and "complain_stderr".
       "$parser->scream( linenumber, complaint string )"
           This notes an error like "whine" does, except that it is not
           suppressible with "no_whining". This should be used only for very
           serious errors.
       "$parser->source_dead(1)"
           This aborts parsing of the current document, by switching on the
           flag that indicates that EOF has been seen.  In particularly
           drastic cases, you might want to do this.  It's rather nicer than
           just calling "die"!
       "$parser->hide_line_numbers( SOMEVALUE )"
           Some subclasses that indiscriminately dump event attributes (well,
           except for ones beginning with "~") can use this object attribute
           for refraining to dump the "start_line" attribute.
       "$parser->no_whining( SOMEVALUE )"
           This attribute, if set to true, will suppress reports of non-fatal
           error messages.  The default value is false, meaning that
           complaints are reported.  How they get reported depends on the
           values of the attributes "no_errata_section" and "complain_stderr".
       "$parser->no_errata_section( SOMEVALUE )"
           This attribute, if set to true, will suppress generation of an
           errata section.  The default value is false -- i.e., an errata
           section will be generated.
       "$parser->complain_stderr( SOMEVALUE )"
           This attribute, if set to true will send complaints to STDERR.  The
           default value is false -- i.e., complaints do not go to STDERR.
       "$parser->bare_output( SOMEVALUE )"
           Some formatter subclasses use this as a flag for whether output
           should have prologue and epilogue code omitted. For example,
           setting this to true for an HTML formatter class should omit the
           "<html><head><title>...</title><body>..." prologue and the
           "</body></html>" epilogue.
           If you want to set this to true, you should probably also set
           "no_whining" or at least "no_errata_section" to true.
       "$parser->preserve_whitespace( SOMEVALUE )"
           If you set this attribute to a true value, the parser will try to
           preserve whitespace in the output.  This means that such formatting
           conventions as two spaces after periods will be preserved by the
           parser.  This is primarily useful for output formats that treat
           whitespace as significant (such as text or *roff, but not HTML).
       "$parser->parse_empty_lists( SOMEVALUE )"
           If this attribute is set to true, the parser will not ignore empty
           "=over"/"=back" blocks. The type of "=over" will be empty,
           documented above, "events with an element_name of over-empty".
SEE ALSO
       Pod::Simple -- event-based Pod-parsing framework
       Pod::Simple::Methody -- like Pod::Simple, but each sort of event calls
       its own method (like "start_head3")
       Pod::Simple::PullParser -- a Pod-parsing framework like Pod::Simple,
       but with a token-stream interface
       Pod::Simple::SimpleTree -- a Pod-parsing framework like Pod::Simple,
       but with a tree interface
       Pod::Simple::Checker -- a simple Pod::Simple subclass that reads
       documents, and then makes a plaintext report of any errors found in the
       document
       Pod::Simple::DumpAsXML -- for dumping Pod documents as tidily indented
       XML, showing each event on its own line
       Pod::Simple::XMLOutStream -- dumps a Pod document as XML (without
       introducing extra whitespace as Pod::Simple::DumpAsXML does).
       Pod::Simple::DumpAsText -- for dumping Pod documents as tidily indented
       text, showing each event on its own line
       Pod::Simple::LinkSection -- class for objects representing the values
       of the TODO and TODO attributes of L<...> elements
       Pod::Escapes -- the module the Pod::Simple uses for evaluating E<...>
       content
       Pod::Simple::Text -- a simple plaintext formatter for Pod
       Pod::Simple::TextContent -- like Pod::Simple::Text, but makes no effort
       for indent or wrap the text being formatted
       Pod::Simple::HTML -- a simple HTML formatter for Pod
       perlpod
       perlpodspec
       perldoc
SUPPORT
       Questions or discussion about POD and Pod::Simple should be sent to the
       pod-people AT perl.org mail list. Send an empty email to
       pod-people-subscribe AT perl.org to subscribe.
       This module is managed in an open GitHub repository,
       <https://github.com/theory/pod-simple/>;. Feel free to fork and
       contribute, or to clone <git://github.com/theory/pod-simple.git>; and
       send patches!
       Patches against Pod::Simple are welcome. Please send bug reports to
       <bug-pod-simple AT rt.org>.
COPYRIGHT AND DISCLAIMERS
       Copyright (c) 2002 Sean M. Burke.
       This library is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.
       This program is distributed in the hope that it will be useful, but
       without any warranty; without even the implied warranty of
       merchantability or fitness for a particular purpose.
AUTHOR
       Pod::Simple was created by Sean M. Burke <sburke AT cpan.org>.  But don't
       bother him, he's retired.
       Pod::Simple is maintained by:
       o   Allison Randal "allison AT perl.org"
       o   Hans Dieter Pearcey "hdp AT cpan.org"
       o   David E. Wheeler "dwheeler AT cpan.org"

perl v5.16.3                      2013-05-03       Pod::Simple::Subclassing(3)