XML-Struct - Represent XML as data structure preserving element order

use XML::Struct qw(readXML writeXML simpleXML);

my $xml = readXML( "input.xml" );
# [ root => { xmlns => 'http://example.org/' }, [ '!', [ x => {}, [42] ] ] ]

my $doc = writeXML( $xml );
# <?xml version="1.0" encoding="UTF-8"?>
# <root xmlns="http://example.org/">!<x>42</x></root>

my $simple = simpleXML( $xml, root => 'record' );
# { record => { xmlns => 'http://example.org/', x => 42 } }

XML::Struct implements a mapping between XML and Perl data structures. By default, the mapping preserves element order, so it also suits for "document-oriented" XML. In short, an XML element is represented as array reference with three parts:

[ $name => \%attributes, \@children ]

This data structure corresponds to the abstract data model of MicroXML, a simplified subset of XML.

If your XML documents don't contain relevant attributes, you can also choose to map to this format:

[ $name => \@children ]   # element without attributes
[ $name ]                 # empty tag without attributes

Both parsing (with XML::Struct::Reader or function readXML) and serializing (with XML::Struct::Writer or function writeXML) are fully based on XML::LibXML, so performance is better than XML::Simple and similar to XML::LibXML::Simple.

• XML::Struct::Reader

  Parse XML as stream into XML data structures.

• XML::Struct::Writer

  Write XML data structures to XML streams for serializing, SAX processing, or creating a DOM object.

• XML::Struct::Writer::Stream

  Simplified SAX handler for XML serialization.

• XML::Struct::Simple

  Transform XML data structure into simple form.

The following functions are exported on request:

Read an XML document with XML::Struct::Reader. The type of source (string, filename, URL, IO Handle...) is detected automatically. See XML::Struct::Reader for options. Options not known to XML::Struct::Reader are passed to XML::LibXML::Reader.

Write an XML document/element with XML::Struct::Writer. See XML::Struct::Writer for options.

Transform an XML document/element into simple key-value format as known from XML::Simple. See XML::Struct::Simple for options.

Transform XML structure with attributes to XML structure without attributes. The function does not modify the passed element but creates a modified copy.

this function is deprecated and will be removed in a future release!

To give an example, with XML::Struct::Reader, this XML document:

<root>
  <foo>text</foo>
  <bar key="value">
    text
    <doz/>
  </bar>
</root>

is transformed to this structure:

[
  "root", { }, [
    [ "foo", { }, "text" ],
    [ "bar", { key => "value" }, [
      "text", 
      [ "doz", { }, [ ] ]
    ] 
  ]
]

This module also supports a simple key-value (aka "data-oriented") format, as used by XML::Simple. With option simple (or function simpleXML) the document given above would be transformed to this structure:

{
    foo => "text",
    bar => {
        key => "value",
        doz => {}
    }
}

This module was first created to be used in Catmandu::XML and turned out to also become a replacement for XML::Simple. See the former for more XML processing.

XML::Twig is another popular and powerfull module for stream-based processing of XML documents.

See XML::Smart, XML::Hash::LX, XML::Parser::Style::ETree, XML::Fast, and XML::Structured for different representations of XML data as data structures (feel free to implement converters from/to XML::Struct). XML::GenericJSON seems to be an outdated and incomplete attempt to capture more parts of XML Infoset in another data structure.

See JSONx for a kind of reverse direction (JSON in XML).

This software is copyright (c) 2014 by Jakob Voß.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.