He has a long record of previous work in programming languages, compiler technology, and software architecture.

[2] His recent work on the NICAD clone detector[3] with Ph.D. student Chanchal Roy, the Recognition Strategy Language[4] with Ph.D. student Richard Zanibbi and Dorothea Blostein, the Cerno[5] lightweight natural language understanding system with John Mylopoulos and others at the University of Trento, and the SIMONE model clone detector with Manar Alalfi, Thomas R. Dean, Matthew Stephan and Andrew Stevenson[6] is based on TXL.

The 1995 paper A Syntactic Theory of Software Architecture[7] with Ph.D. student Thomas R. Dean has been widely cited as a seminal work in the area, and led to his work with Thomas R. Dean, Kevin A. Schneider and Andrew J. Malton on legacy systems analysis.

[16] He has co-authored or co-edited the books The Turing Programming Language: Design and Definition[17] (1988), Introduction to Compiler Construction Using S/SL[18] (1986), The Smart Internet[19] (2010), and The Personal Web[20] (2013).

[21] He is a prolific academic supervisor and in 2008 was recognized with the Queen's University Award of Excellence in Graduate Supervision.