Beautiful Architecture

Acknowledgments

I am grateful to several people who made important comments on drafts of this contribution; obviously, acknowledgment implies no hint of endorsement (as is obvious in the case of the functional programming grandees who were kind enough to share constructive reactions without, I fear, being entirely swayed yet by my argument). Particularly relevant were observations by Simon Peyton Jones, Erik Meijer, and Diomidis Spinellis. John Hughes’s answer to my questions about his classic paper were detailed and illuminating. The Visitor library discussed in the last part of this chapter is the work of Karine Arnout (Karine Bezault). I thank Gloria Müller for further observations as part of an ETH master’s thesis on implementing a library of Haskell-like facilities for Eiffel. I am especially grateful to the editors of this volume, Diomidis Spinellis and Georgios Gousios, for the opportunity to publish this discussion and for their extreme patience with my delays in finalizing it.