Many applications which process data-centric XML do that based
on a nice specification, expressed in an XML Schema.
XML::Compile reads and writes XML data with the help of such
schema's. On the Perl side, it uses a tree of nested hashes
with the same structure.

Where other Perl modules, like SOAP::WSDL help you using these
schema's (often with a lot of run-time (XPath) searches), this
module takes a different approach: in stead of run-time
processing of the specification, it will first compile the
expected structure into real Perl, and then use that to process
the data.

There are many perl modules with the same as this one: translate
between XML and nested hashes. However, there are a few serious
differences: because the schema is used here, we make sure we
only handle correct data. Data-types are formatted and processed
correctly; for instance, integer does accept huge values
(at least 18 digits) as the specification prescribes. Also more
complex data-types like list, union, and substitutionGroup
(unions on complex type level) are supported, which is rarely the
case in other modules.

WWW: https://metacpan.org/release/XML-Compile