A remarkable group photo






On 13-15 September 1999 a symposium took place in St Catherine College in Oxford,  in honor of Tony Hoare’s “retirement” from Oxford (the word is in quotes because he has had several further productive careers since). The organizers were Jim Woodcock, Bill Roscoe and Jim Davies. The proceedings are available as Millenial Perspectives in Computer … Read more




Niklaus Wirth and the Importance of Being Simple






[This is a verbatim copy of a post in the Communications of the ACM blog, 9 January 2024.] I am still in shock from the unexpected death of Niklaus Wirth eight days ago. If you allow a personal note (not the last one in this article): January 11, two days from now, was inscribed in … Read more




Introduction to the Theory of Programming Languages: full book now freely available






Short version: the full text of my Introduction to the Theory of Programming Languages book (second printing, 1991) is now available. This page has more details including the table of chapters, and a link to the PDF (3.3MB, 448 + xvi pages). The book is a survey of methods for language description, particularly semantics (operational, … Read more




Why stop at pronouns?






My adjectives: timid, arrogant, insufferable. My adverbs: (just one in fact) inadvertently My gerunds: painstaking, running away, whining My verbs: irritate, disappoint My prepositions: notwithstanding, in spite of, away from My conjunction: even though




Adult entertainment






Sign seen in a Singapore shopping center:   Let us make sure we understand: here children are not allowed, but playing is. As a consequence such playing must be performed by non-children only. Adults welcome to play! Maybe it is actually not the intended meaning.  Instead of (and (not (allowed children)) (allowed playing)) the desired … Read more




Ten traits of exceptional innovators






Imagine having had coffee, over the years, with each of Euclid, Galileo, Descartes, Marie Curie, Newton, Einstein, Lise Leitner, Planck and de Broglie. For a computer scientist, if we set aside the founding generation (the Turings and von Neumanns), the equivalent is possible. I have had the privilege of meeting and in some cases closely … Read more