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############################################################################## |
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# |
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# Perl module: XML::XUpdate::Rewrite |
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# |
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# By Andreas Motl, andreas.motl@ilo.de |
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# |
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# $Id: Rewrite.pm,v 1.1 2003/05/06 14:36:48 joko Exp $ |
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# |
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# $Log: Rewrite.pm,v $ |
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# Revision 1.1 2003/05/06 14:36:48 joko |
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# initial commit - preliminary (didn't work out as expected) |
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# |
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# |
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############################################################################### |
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|
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|
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=pod |
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|
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=head1 NAME |
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XML::XUpdate::Rewrite - A perl module for rewriting xml documents. |
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=head1 VERSION |
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|
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$Revision: 1.1 $ |
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$Date: 2003/05/06 14:36:48 $ |
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|
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=head1 DESCRIPTION |
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|
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=head2 ABOUT |
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|
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Pass through data of xml document untouched, |
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just modify its layout and/or descriptive information. |
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|
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Layout manipulation: |
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- Node indentation level control and similar to optimize for human or machine readable payloads. |
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|
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Descriptive information: |
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- Control if and how to produce the starting (e.g.) <?xml version="1.0" encoding="UTF-8"?> line. |
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- Toggle root node encapsulation on/off, specify root node. |
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|
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Note for CPAN maintainers: |
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This would in fact make a general purpose module(???), it´s just in this namespace because |
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it was developed together with XML::XUpdate::XSLT. |
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Better name: XML::Rewrite? Or completely different - XML::Passthru. Or - associated to |
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its main usage - XML::ParseWriter. The "descriptive information encapsulation" could make |
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up a XML::Encap. |
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Both things in mind, let´s find a more abstract name combining its intention but |
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"one level away" from its core functionality!? e.g. XML::Smooth? XML::Polish? |
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|
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=head2 IMPLEMENTATION |
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|
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It was started using XML::Parser::PerlSAX and its companions XML::Handler::XMLWriter |
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and XML::Handler::CanonXMLWriter. This did *not* exactly solve the problem on the |
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first attempt, but was more simple to achieve through information provided by their |
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core pods. |
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The XML::Parser vs. XML::Writer way seems to be more straightforward and better |
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to customize by a richer set of parameters closer reflecting the intention of this module. |
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(convenient highlevel wrapper just doing a subset of what´s possible at all) |
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=head1 TODO |
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|
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o Handle / convert between other important representations of XML documents (e.g. from/to XML::DOM) |
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This [c|w]ould make a XML::Convert or Convert::XML??? Does already exist one on CPAN? |
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o Provide some hooks to (e.g.) enable possibility to convert values from Latin to UTF-8 or such stuff. |
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|
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|
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=cut |
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|
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###################################################################### |
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package XML::XUpdate::Rewrite; |
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###################################################################### |
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|
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use strict; |
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use warnings; |
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use vars qw ( $VERSION ); |
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|
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use Data::Dumper; |
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# To load perl modules on demand at runtime. |
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# Perl will not croak at compile time for missing modules. |
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use Class::Loader; |
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#use base qw( Class::Loader ); |
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$VERSION = '0.01'; |
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|
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###################################################################### |
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# PUBLIC DEFINITIONS |
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|
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sub new { |
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my $class = shift; |
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my $self = bless {}, $class; |
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$self->{options} = $self->__arglist2hash(@_); |
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|
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$self->{DEBUG} = $self->{options}->{debug}; |
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$self->{WARNINGS} = $self->{options}->{warnings}; |
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return $self; |
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} |
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sub set_document { |
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my $self = shift; |
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my $xml = shift; |
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$self->{XML}->{document} = $xml; |
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} |
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sub get_document { |
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my $self = shift; |
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return $self->{XML}->{document}; |
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} |
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sub process { |
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my $self = shift; |
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# are we here? |
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#print "YAI!", "\n"; |
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# set default options (in case just "rewrite" is turned on) |
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# a) canonical mode using XML::Parser::PerlSAX |
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$self->{options}->{engine} ||= "PerlSAX"; |
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$self->{options}->{style} ||= "canonical"; |
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# b) human readable xml using XML::Parser vs. XML::Writer |
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$self->{options}->{engine} ||= "XMLParser"; |
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$self->{options}->{style} ||= "readable"; |
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my $raw = $self->get_document(); |
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# Rewrite xml payload to change output style of raw document (human readable or canonical). |
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# TODO: use XML::Writer as third option! |
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# from its pod: [...] and elements can optionally be indented based as their nesting level. |
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# FIXME: Do on-demand loading of helper modules here. |
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# V1 - The PerlSAX way. |
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if ($self->{options}->{engine} eq "PerlSAX") { |
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# First, create writer instance ... |
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my $writer; |
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if ($self->{options}->{style} eq "readable") { |
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# V1 - static |
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#use XML::Handler::XMLWriter; |
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#$writer = XML::Handler::XMLWriter->new( AsString => 1, Newlines => 0 ); |
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# V2 - dynamic |
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#$writer = Class::Loader::_load( undef, |
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# Module => 'XML::Handler::XMLWriter', |
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# Args => [ AsString => 1, Newlines => 0 ], |
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#); |
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# V3 - auxiliary method |
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$writer = $self->__load( "XML::Handler::XMLWriter", [ AsString => 1, Newlines => 0 ] ); |
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} elsif ($self->{options}->{style} eq "canonical") { |
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# FIXME: Make this work again! |
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#use XML::Handler::CanonXMLWriter; |
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#$writer = XML::Handler::CanonXMLWriter->new( PrintComments => 1 ); |
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} |
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# pre-flight checks (do we actually have a writer instance?) |
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die( __PACKAGE__ . ": No writer instance!" ) if (not $writer or not ref $writer); |
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# ... and then create the parser instance. |
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my $parser = $self->__load( "XML::Parser::PerlSAX" ); |
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# more pre-flight checks |
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die( __PACKAGE__ . ": No parser instance!") if (not $parser or not ref $parser); |
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# Finally, run them together, overwrite our payload ... |
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$self->set_document( $parser->parse( Source => { String => $raw }, Handler => $writer ) ); |
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# ... and signal good. |
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return 1; |
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} |
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# V2 - using the classic XML::Parser together with its companion, XML::Writer |
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if ($self->{options}->{engine} eq "XMLParser") { |
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use IO::File; |
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my $output = IO::File->new(">output.xml"); |
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# These return instances which are not required. => overhead! |
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$self->__load("XML::Writer"); |
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$self->__load("XML::Parser::StreamWriter"); |
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# First, create the writer instance ... |
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#my $writer = XML::Writer->new( OUTPUT => $output, NEWLINES => 0, DATA_MODE => 1, DATA_INDENT => 2 ); |
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my $writer = XML::Writer->new( OUTPUT => *STDERR, NEWLINES => 0, DATA_MODE => 0, DATA_INDENT => 2 ); |
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# ... and pass it through expat to the stream handler. |
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my $parser = XML::Parser->new( Style => "Stream", Pkg => "XML::Parser::StreamWriter", Writer => $writer ); |
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# Run that stuff... |
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$parser->parse( $raw ); |
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# Like above ... |
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#$self->set_document( $parser->parse( $raw ) ); |
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#return 1; |
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} |
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return 0; |
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} |
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###################################################################### |
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# AUXILIARY METHODS |
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# Argument list parsing. |
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# ... from XML::XUpdate::LibXML (w/o backwards compatibility hook). |
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# Could this make up a Class::AutoFill::__read_arglist which transparently |
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# makes object attributes from constructor arguments in a configurable way? |
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# also similar inside XML::XUpdate::XSLT!!! |
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# solution: do some mixin here!!! --> Class::Container!? |
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sub __arglist2hash { |
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my $self = shift; |
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my %args; |
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if ( @_ % 2 ) { |
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$args{dummy} = shift; |
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%args = (%args, @_); |
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} else { |
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%args = @_; |
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} |
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return \%args; |
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} |
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sub __load { |
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my $self = shift; |
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my $name = shift; |
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my $args = shift; |
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return Class::Loader::_load( undef, Module => $name, Args => $args ); |
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} |
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1; |
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__END__ |
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