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XML-Compile-0.17
River stage two • 40 direct dependents • 68 total dependents
/ XML::Compile

NAME

XML::Compile - Compilation based XML processing

SYNOPSIS

 # See XML::Compile::Schema

DESCRIPTION

Many professional applications which process XML do that based on a formal specification, expressed as XML Schema. XML::Compile processes <b>data-centric XM"b" with the help of such schema's. On the Perl side, this module creates a tree of nested hashes with the same structure as the XML.

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

There are many perl modules with the same intention as this one: translate between XML and nested hashes. However, there are a few serious differences: because the schema is used here (and not in the other modules), we can validate the data. XML requires validation but quite a number of modules simply ignore that. Next to this, data-types are formatted and processed correctly; for instance, the specification prescribes that the Integer data-type must accept values of at least 18 digits... not just longs. Also more complex data-types like list, union, substitutionGroup (unions on complex type level), and any/anyAttribute are supported, which is rarely the case for the other modules.

In general two WARNINGS:

.

The compiler does not support non-namespace schema's and mixed elements.

.

The provided schema is not validated! In some cases, compile-time and run-time errors will be reported, but typically only in cases that the parser has no idea what to do with such a mistake. On the other hand, the processed data is validated: the output will follow the specs closely.

For end-users, the following packages are interesting (the other are support packages):

XML::Compile::Schema

Interpret schema elements and types.

XML::Compile::WSDL

Interpret WSDL files.

XML::Compile::Dumper

Save pre-compiled converters in pure perl packages.

METHODS

Constructors

These constructors are base class methods to be extended, and therefore should not be accessed directly.

XML::Compile->new(TOP, OPTIONS)

    The TOP is the source of XML. See dataToXML() for valid options.

    If you have compiled/collected all readers and writers you need, you may simply terminate the compiler object: that will clean-up (most of) the XML::LibXML objects.

     Option     --Default
 schema_dirs  undef

    . schema_dirs DIRECTORY|ARRAY-OF-DIRECTORIES

      Where to find schema's. This can be specified with the environment variable SCHEMA_DIRECTORIES or with this option. See addSchemaDirs() for a detailed explanation.

Accessors

$obj->addSchemaDirs(DIRECTORIES)

    Each time this method is called, the specified DIRECTORIES will be added in front of the list of already known schema directories. Initially, the value of the environment variable SCHEMA_DIRECTORIES is added (therefore used last), then the constructor option schema_dirs is processed.

    Values which are undef are skipped. ARRAYs are flattened. Arguments are split on colons (only when on UNIX) after flattening.

$obj->findSchemaFile(FILENAME)

    Runs through all defined schema directories (see addSchemaDirs()) in search of the specified FILENAME. When the FILENAME is absolute, that will be used, and no search will take place. An undef is returned when the file is not found or not readible, otherwise a full path to the file is returned to the caller.

$obj->knownNamespace(NAMESPACE)

XML::Compile->knownNamespace(NAMESPACE)

    Returns the file which contains the definition of a NAMESPACE, if it is one of the set which is distributed with the XML::Compile module.

Read XML

$obj->dataToXML(NODE|REF-XML|XML|FILENAME|KNOWN)

    Collect XML data. Either a preparsed NODE is provided, which is returned unchanged. A ref of SCALAR is interpreted as reference to XML as plain text (XML texts can be large, hence you can improve performance by passing it around as reference in stead of copy). Any value which starts with blanks followed by a "<" is interpreted as XML text.

    You may also specify a pre-defined (KNOWN) name-space. A set of definition files is included in the distribution, and installed somewhere when the modules got installed. Either define an environmen variable SCHEMA_LOCATION or use new(schema_dirs) to inform the library where to find these files.

$obj->parse(STRING)

    Extract document element tree from the STRING, which represents XML. This is a wrapper around XML::LibXML method parse_string().

$obj->parseFile(FILENAME)

    Extract document element tree from a file, specified by FILENAME. This is a wrapper around XML::LibXML method parse_file().

Filters

$obj->walkTree(NODE, CODE)

    Walks the whole tree from NODE downwards, calling the CODE reference for each NODE found. When that routine returns false, the child nodes will be skipped.

DIAGNOSTICS

Error: cannot find pre-installed name-space files

Use $ENV{SCHEMA_LOCATION} or new(schema_dirs) to express location of installed name-space files, which came with the XML::Compile distribution package.

Error: don't known how to interpret XML data

Error: no XML data specified

SEE ALSO

This module is part of XML-Compile distribution version 0.17, built on March 20, 2007. Website: http://perl.overmeer.net/xml-compile/

LICENSE

Copyrights 2006-2007 by Mark Overmeer.For other contributors see ChangeLog.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See http://www.perl.com/perl/misc/Artistic.html