Peter J. Landin

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Peter John Landin (born June 5, 1930 in Sheffield , † June 3, 2009 ) was a British computer scientist . He was one of the pioneers of computer science, whose work from the early 1960s had a profound influence on the development of programming languages . They drew attention to the 'applicative core' of programming languages, an insight of great importance for the development of functional programming languages and denotational semantics .

Peter Landin studied at the University of Cambridge . From 1960 to 1964 he was assistant to Christopher Strachey , who was a freelance IT consultant in London at the time. Most of his publications date from this time and the short time he worked at Univac in the United States . He was then appointed to the Queen Mary College of the University of London , where he was entrusted with setting up computer science. He devoted himself to this in the 1970s and 1980s, developing courses and teaching theoretical computer science. Even after his retirement he stayed at the college as a teacher.

At a meeting on the history of the semantics of programs at the Science Museum in London in 2001, he reported on the beginning of his scientific career in computer science in the late 1950s and how much he was influenced by studying John McCarthy's programming language LISP , and at a time when Fortran was the most widely used programming language.

He took an active part in the definition of the ALGOL programming language . and wrote one of the first formal descriptions of this programming language. Tony Hoare describes him as one of the people who taught him Algol 60, allowing him to formulate powerful recursive algorithms :

“Around Easter 1961, an ALGOL 60 course was held in Brighton, England with Peter Naur , Edsger W. Dijkstra , and Peter Landin as speakers. It was there that I learned about recursive procedures for the first time and saw how one should actually write the program that I used to be so difficult to explain. On the spot, I wrote the procedure that I immodestly called QUICKSORT and on which my career as a computer scientist is based. The credit for this is due to the genius of the developers of ALGOL 60, who allowed recursion in their language and thus enabled me to describe my invention so elegantly for the world. I have always considered it the ultimate goal of programming language design to enable the elegant expression of good ideas. "

Landin is also responsible for the invention of the SECD machine and the ISWIM programming language , and also invented the off-side rule for programming languages ​​and the term syntactic sugar . The off-side rule allows sections within programs to be defined using white space and is used in the Miranda , Haskell and Python languages, among others .

Another way of speaking that goes back to Landin is “The next 700…” after his momentous work The next 700 programming languages . Landin chose the number 700 because he had read in a report by the American Mathematical Association that there were 1700 programming languages ​​at that time to 'communicate' in over 700 areas of application. With the programming language ISWIM , which he conceived in this lecture, he would have created 700 programming languages ​​in one fell swoop, since ISWIM as a core should be supplemented by application-specific elements. It also contains the joking remark

"A possible step in the research program would be the preparation of 1700 doctoral theses with the title A Correspondence between x and Church's λ-notation "

a nod to his previous work. This type of dry humor is found in many of his publications.

Important publications

  • The mechanical evaluation of expressions . The Computer Journal , vol 6 (1964), no. 4. pp. 308-320
  • A correspondence between ALGOL 60 and Church's lambda notation . Commun. ACM 8, 89-101, 158-165.
  • The next 700 programming languages . Commun. ACM 9,3,157-166.

Individual evidence

  1. a b Peter Landin , Lambda the Ultimate , June 4, 2009.
  2. ^ Acknowledged in the forward to the text book Programming from First Principles by Richard Bornat . Published by Prentice Hall , 1987. ISBN 9780137291045 .
  3. ^ Program Verification and Semantics: Report ( Memento of September 26, 2007 in the Internet Archive ), 2001.
  4. Listed amongst those who attended the November 1959 conference in [Paris] [1] and the 1962 conference [2] .
  5. ^ PJ Landin: A formal description of Algol 60 . In Steel [Ste64], pages 266-294.
  6. ^ ACM Turing Award Lecture: The Emperor's Old Clothes . C. Antony R. Hoare , 1980, Published in the Communications of the ACM .
  7. Peter J. Landin: The next 700 programming languages Archived from the original on September 2, 2006. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Communications of the ACM . 9, No. 3, March 1966, pp. 157-166. doi : 10.1145 / 365230.365257 . Retrieved October 18, 2006.  @1@ 2Template: Webachiv / IABot / www.cs.utah.edu
  8. ^ Computer Software Issues, an American Mathematical Association Prospectus, July 1965.
  9. ^ A correspondence between ALGOL 60 and Church's Lambda notation . Comm. ACM, 8: 89-101 (1965); 158-165.

Web links