=encoding utf8

=head1 NAME

XML::Compile::Util - Utility routines for XML::Compile components

=head1 INHERITANCE

 XML::Compile::Util
   is a Exporter

=head1 SYNOPSIS

 use XML::Compile::Util;
 my $node_type = pack_type $ns, $localname;
 my ($ns, $localname) = unpack_type $node_type;

=head1 DESCRIPTION

The functions provided by this package are used by various XML::Compile
components, which on their own may be unrelated.

=head1 FUNCTIONS

=head2 Constants

The following URIs are exported as constants, to avoid typing
in the same long URIs each time again: XMLNS, SCHEMA1999,
SCHEMA2000, SCHEMA2001, and SCHEMA2001i.

=head2 Packing

=over 4

=item B<pack_id>($ns, $id)

Translates the two arguments into one compact string representation of
the node id.

example: 

 print pack_id 'http://my-ns', 'my-id';
 # shows:  http://my-ns#my-id

=item B<pack_type>( [$ns], $localname )

Translates the arguments into one compact string representation of
the node type.  When the $ns is not present, C<undef>, or an
empty string, then no namespace is presumed, and no curly braces
part made.

example: 

 print pack_type 'http://my-ns', 'my-type';
 # shows:  {http://my-ns}my-type 

 print pack_type 'my-type';
 print pack_type undef, 'my-type';
 print pack_type '', 'my-type';
 # all three show:   my-type

=item B<unpack_id>($string)

Returns a LIST of two elements: the name-space and the id, as
included in the $string.  That $string must be compatible with the
result of L<pack_id()|XML::Compile::Util/"Packing">.

=item B<unpack_type>($string)

Returns a LIST of two elements: the name-space and the localname, as
included in the $string.  That $string must be compatible with the
result of L<pack_type()|XML::Compile::Util/"Packing">.  When no name-space is present, an empty
string is used.

=back

=head2 Other

=over 4

=item B<add_duration>( $duration, [$time] )

[1.44] Add the $duration to the $time (defaults to 'now')  This is an
expensive operation: in many cases the L<duration2secs()|XML::Compile::Util/"Other"> produces
useful results as well.

example: 

   my $now      = time;
   my $deadline = add_duration 'P1M', $now;  # deadline in 1 month

=item B<duration2secs>($duration)

[1.44] Translate any format into seconds.  This is an example of
a valid duration: C<-PT1M30.5S>  Average month and year lengths
are used.  If you need more precise calculations, then use L<add_duration()|XML::Compile::Util/"Other">.

=item B<even_elements>(LIST)

Returns the even-numbered elements from the LIST.

=item B<odd_elements>(LIST)

Returns the odd-numbered elements from the LIST.

=item B<type_of_node>($node)

Translate an XML::LibXML::Node into a packed type.

=back

=head1 SEE ALSO

This module is part of XML-Compile distribution version 1.56,
built on March 30, 2017. Website: F<http://perl.overmeer.net/xml-compile/>

Please post questions or ideas to the mailinglist at
F<http://lists.scsys.co.uk/cgi-bin/mailman/listinfo/xml-compile> .
For live contact with other developers, visit the C<#xml-compile> channel
on C<irc.perl.org>.

=head1 LICENSE

Copyrights 2006-2017 by [Mark Overmeer]. For other contributors see ChangeLog.

This program is free software; you can redistribute it and/or modify it
under the Artistic license.
See F<http://dev.perl.org/licenses/artistic.html>

