Table of contents

Appendices

5.2 Using XML Processors

The behavior of a validating XML processor is highly predictable; it must read every piece of a document and report all well-formedness and validity violations. Less is required of a non-validating processor; it need not read any part of the document other than the document entity. This has two effects that may be important to users of XML processors:

• Certain well-formedness errors, specifically those that require reading external entities, may fail to be detected by a non-validating processor. Examples include the constraints entitled Entity Declared, Parsed Entity, and No Recursion, as well as some of the cases described as forbidden in [XML Processor Treatment of Entities and References].

• The information passed from the processor to the application may vary, depending on whether the processor reads parameter and external entities. For example, a non-validating processor may fail to normalize attribute values, include the replacement text of internal entities, or supply default attribute values, where doing so depends on having read declarations in external or parameter entities.

For maximum reliability in interoperating between different XML processors, applications which use non-validating processors SHOULD NOT rely on any behaviors not required of such processors. Applications which require DTD facilities not related to validation (such as the declaration of default attributes and internal entities that are or may be specified in external entities SHOULD use validating XML processors.