The 'expp' tool (the Epeios XML preprocessor) reads an XML file to transform it to another XML file. It simplifies the writing of XML files by allowing the handling of macros, the definition and testing of variables, the inclusion of files, and more. This is done by writing, directly in the source XML file, predefined tags owned by a given namespace, tags which are then recognized and handled by the 'expp' tool. The tool is also available as a Java native component.

'expp' (both the command-line version and the Java version) can now be compiled in 32 bits ('IA-32') and in 64 bits ('x86-64'). It accurately handles UTF-8 files with and without BOM. There is also a new directive ('cdata'), which can be used if you want to enclose an XML tree in an XML CDATA section, and the preprocessor still issues an error if the enclosed XML tree is not well-formed

The Epeios XML preprocessor – Freecode