Things from David Tolpin


05/01/2005 RNV updated

A bug in xsd implementation is fixed; base64binaries are now compared correctly. Added that to the testsuite.

19/08/2004 RNV and XX updated

One bug fixed in each; both were easy to fix but in rarely used areas; I added tests for these cases to my suite.

15/06/2004 Zenteq

Since April, I am busy 24 hours per day launching a new team; all my personal projects are on hold. Hopefully, best of them will continue to be developed in Zenteq.

27/03/2004 RNV and XX

RNV 1.7 — entities expansion is moved out of RNV to XX.

XX 1.1 — initial release; a simple utility to expand entities in XML documents. Based on Expat.

More details in

Current Projects

  • XZ

  • XX - XML preprocessor.

  • ARX - Regular Associations for XML. ARX is included in RNV distribution.

  • RNV - Relax NG Compact Syntax validator in ANSI C. RNV is a part of PreTI.

  • PreTI - computer-aided input of structured documents.

  • more to come soon.

Past Projects


Re-implementation of Franklin Liang's TeX hyphenation algorithm in Java.

XEP - XSL FO Formatter

I spent four years working on RenderX XSL FO Formatter as a coder, the development team's leader and CTO, all at the same time. This is a commercial product, thus the source code is not available. But a working piece of software is, and hopefully will be for a rather long time.

Hragir - Armenian webmail

Hragir had been deployed in 1998 and put down in 2003 after running unattended for a year since I had left the American University of Armenia. Traces of the original site are archived at

pOt - portable Oberon translator

That was a very nice programming experience. Last change had been made in 1994, but I still use it occasionally for teaching and programming. The source code is self-compiling, and the footprint of the compiler is tiny by today's merits.

Many others.

Frequently Asked Question

Who is David Ashen?

I don't care. 'Davida-shen' stands for 'built by David' in Armenian, that is, by me, David Tolpin.

More to come soon.

CV misc