Trip report E.W. Dijkstra, Amsterdam 26-29 Oct. 1981

IFIP's TC2 and the Mathematical Centre in Amsterdam had organised a four-day "International Symposium on Algorithmic Languages" at the occasion of prof.dr.ir. A. van Wijngaarden's retirement as director of the Mathematical Centre.

On Saturday morning Ria and I drove to Schiphol to collect prof.dr. W.M. Turski (from Warsaw) and prof.dr. A.P. Ershov (from Novosibirsk), who stayed the weekend with us in Nuenen. (It was well-organized: their planes landed 10 minutes apart!) It was a very nice weekend; on Sunday afternoon we were joined by Femke, who first spoke for an hour Russian with Ershov and then exercised for more than two hours the pronunciation of Polish with Turski. The weekend gave Ershov the opportunity to absorb some of the six-hour time shift.

On Monday morning we took the 8.06 train to Amsterdam Amstel, where we took a cab; at 9.35 we were at the Mathematical Centre, where the symposium was held. During the next four days we had plenty of opportunity to explore the Amsterdam public transport system: we were lodged in the International Centre of the Royal Tropical Institute, on Monday evening we had a reception in the Stedelijk Museum, on Tuesday evening van Wijngaarden gave a dinner to friends in the Rosarium, and on Wed-

nesday evening we had the Conference Dinner in the Lido at the Leidse Plein.

As member of the Program Committee I knew that it would not be a very good conference; apparently the computing community had sensed this, for there were only about 125 participants. There were three invited talks on van Wijngaarden's role: Heinz Zemanek (re IFIP), Peter Naur (re ALGOL 60) and Wlad Turski (re ALGOL 68). All three talks were well-prepared and well-presented. Good technical talks were given by R. Schild (from Switzerland), B. Meyer (from France), M. Broy (from Germany), M. Sato (from Japan) and J.C. Reynolds (from the USA). I found J. Darlington (from the UK) again totally unconvincing; J. Backus (from the USA) caused grave disappointment. J.D. Roberts (from the UK) baffled his audience, D. de Champeaux (from the Netherlands) insulted it by the lousiness of his presentation. H.S. Warren (from the USA) spoke about his thesis topic (under Schwarz at NYU), which was remarkably foolish, and all the rest I found rather boring. We had woolly talks --about "the user" and "the beginning programmer"--; some of the more mathematical papers most definitely lacked the effectiveness that is so dear to me. For lack of submitted papers the presentation of each had been allotted 40 minutes and on the average this was too much. (Independently of each other, two speakers of the Mathematical Centre filled half their slot by defining

the notion of a transitive closure!)

The conference quite clearly suffered from the fact that it had been organised in honour of van Wijngaarden, who was sitting in the front row. A number of speakers really deserved to be torn apart, but the audience did not do it (or the chairman did not allow it) for fear of spoiling the fun for van Wijngaarden.

Turski's closing speech was magnificent. Belonging to the famous "minority" that left W.G.2.1 in protest in 1968, he should never have been asked to talk about van Wijngaarden and ALGOL 68. He solved his problem by treating ALGOL 68 as a mistake carried through to perfection, giving van Wijngaarden the credit for the latter, and W.G.2.1 the blame for the first. It was a very subtle balance!

On Thursday afternoon I was back home in time for dinner.