xml::handler::xmlwriter(3)
NAME
XML::Handler::XMLWriter - a PerlSAX handler for writing
readable XML
SYNOPSIS
use XML::Parser::PerlSAX;
use XML::Handler::XMLWriter;
$my_handler = XML::Handler::XMLWriter->new( I<OPTIONS> );
XML::Parser::PerlSAX->new->parse(Source => { SystemId =>
'REC-xml-19980210.xml' },
Handler => $my_handler);
DESCRIPTION
"XML::Handler::XMLWriter" is a PerlSAX handler for writing
readable XML (in contrast to Canonical XML, for example).
XML::Handler::XMLWriter can be used with a parser to
reformat XML, with XML::DOM or XML::Grove to write out
XML, or with other PerlSAX modules that generate events.
"XML::Handler::XMLWriter" is intended to be used with
PerlSAX event generators and does not perform any checking
itself (for example, matching start and end element
events). If you want to generate XML directly from your
Perl code, use the XML::Writer module. XML::Writer has an
easy to use interface and performs many checks to make
sure that the XML you generate is well-formed.
"XML::Handler::XMLWriter" is a subclass of "XML::Han
dler::Subs". "XML::Handler::XMLWriter" can be further
subclassed to alter it's behavior or to add element-spe
cific handling. In the subclass, each time an element
starts, a method by that name prefixed with `s_' is called
with the element to be processed. Each time an element
ends, a method with that name prefixed with `e_' is
called. Any special characters in the element name are
replaced by underscores. If there isn't a start or end
method for an element, the default action is to write the
start or end tag. Start and end methods can use the
`"print_start_element()"' and `"print_end_element()"'
methods to print start or end tags. Subclasses can call
the `"print()"' method to write additional output.
Subclassing XML::Handler::XMLWriter in this way is similar
to XML::Parser's Stream style.
XML::Handler::Subs maintains a stack of element names,
`"$self-"{Names}', and a stack of element nodes,
`"$self-"{Nodes}>' that can be used by subclasses. The
current element is pushed on the stacks before calling an
element-name start method and popped off the stacks after
calling the element-name end method.
See XML::Handler::Subs for additional methods.
In addition to the standard PerlSAX handler methods (see
PerlSAX for descriptions), XML::Handler::XMLWriter sup
ports the following methods:
- new( OPTIONS )
- Creates and returns a new instance of XML::Han
dler::XMLWriter with the given OPTIONS. Options may be changed at any time by modifying them directly in
the hash returned. OPTIONS can be a list of key,
value pairs or a hash. The following OPTIONS are sup ported: - Output
An IO::Handle or one of it's subclasses (such as
IO::File), if this parameter is not present and
the AsString option is not used, the module will
write to standard output. - AsString
Return the generated XML as a string from the
`"parse()"' method of the PerlSAX event generator. - Newlines
A true or false value; if this parameter is pre
sent and its value is true, then the module will
insert an extra newline before the closing delim
iter of start, end, and empty tags to guarantee
that the document does not end up as a single,
long line. If the paramter is not present, the
module will not insert the newlines. - IsSGML
A true or false value; if this parameter is pre
sent and its value is true, then the module will
generate SGML rather than XML. - print_start_element($element)
- Print a start tag for `$element'. This is the default
action for the PerlSAX `"start_element()"' handler,
but subclasses may use this if they define a start
method for an element. - print_end_element($element)
- Prints an end tag for `$element'. This is the default
action for the PerlSAX `"end_element()"' handler, but
subclasses may use this if they define a start method
for an element. - print($output)
- Write `$output' to Output and/or append it to the
string to be returned. Subclasses may use this to
write additional output.
TODO
- · An Elements option that provides finer control over
- newlines than the Newlines option, where you can
choose before and after newline for element start and
end tags. Inspired by the Python XMLWriter. - · Support Doctype and XML declarations.
AUTHOR
Ken MacLeod, ken@bitsko.slc.ut.us This module is partially
derived from XML::Writer by David Megginson.