This glossary contains terms that we commonly use on our documentation, website and marketing materials.

General Terms

XML Compare (XML Diff)

XML Compare, commonly referred to as XML Diff, is a comparison of two XML files. Unlike non-XML compare and diff tools, as it has been developed for the ground-up to work with XML. DeltaXML provide the following products for comparing XML files:

  • Core - general XML Comparison toolkit which can be adapted for your bespoke XML data and document formats.
  • DITA Compare - comparison of DITA (Darwin Information Typing Architecture) XML files.
  • DocBook Compare - comparison of DocBook XML files.

XML Merge

XML Merge is the comparison of three or more inputs, creating a result which can have the various changes reconciled to produce a new "merged" result. Currently DeltaXML provide the following products for merging XML file:

  • Merge - merging of three or more XML files.
  • DITAMerge - merging of three or more DITA (Darwin Information Typing Architecture) XML files.

General XML Formats

CALS Table Model

The CALS Table Model is an OASIS standard for representing complex table structures in XML. It is included in multiple other formats, such as DITA and DocBook, and both DITA Compare and DocBook Compare can handle changes to CALS tables.

DeltaXML Technologies

DeltaV2 Format

The DeltaV2 format is an XML representation of differences between two or more XML files. It is produced by our flagship general XML toolkit products, Core and Merge, to allow full flexibility to process the result for your specific requirements.

DeltaV2 Format - Version 2.1

The DeltaV2 Version 2.1 format represents an extension to the base DeltaV2 format, made specifically to describe overlapping XML hierarchies. This format is only used when the Document Comparator component's 'formatting elements' feature is exploited.

DCP (Document Comparator Pipelines) Format

The DCP Format allows for the configuration of the DocumentComparator class, XML filters can also be added at specific extension points in the comparison pipeline. This is provided in Core and is effectively an extension of the DXP format.

DXP (DeltaXML Pipelines) Format

Our DXP Format allows easy configuration of pipelines with filters before or after the comparison. This format can be used with either the PipelinedComparator or PipelinedComparatorS9 class. This is provided in both Core and Merge, and is actually used internally in most of our other products!

Formatting Elements

This term Formatting Elements is used for element used not to define structure but instead to mark text as having a certain format. The Document Comparator in Core, along with other DeltaXML products can perform alignment on the text content of such elements, using a process called 'flattening'. This allows changes in formatting to be represented differently or ignored altogether in the comparison result.

Lexical Preservation

For many documentation workflows making use of XML comparison or merging it is desirable to preserve XML mark-up (such as comments, processing-instructions and entities) in the results - we commonly refer to this as round-tripping. Our lexical preservation enables this by converting this lexical content into XML prior to comparison and converting back when serializing the result.


In XML, PCDATA is a single block of text. However, when comparing XML files it is desirable to detect and represent changes at a the word granularity. Our Word-by-Word processing achieves this by using a pre-comparison filter to break PCDATA down into word, space and punctuation elements, and a post-comparison filter to reconstruct back to PCDATA (with changes marked up using the DeltaV2 format).