Peter J. Landin

Peter Landin is a British computer scientist. He was one of the first to realize that the lambda calculus could be used to model a programming language, an insight that is essential to development of both functional programming and denotational semantics.

He graduated from Cambridge University. From 1960 to 1964 he was the assistant to Christopher Strachey when the latter was an independent computer consultant. Most of his work was published during this period and the brief time he worked for Univac in the United States before taking a position Queen Mary, University of London. During the 1970s and 1980s his efforts went into building the Computer Science department in Queen Mary College, developing courses and teaching students.fact|date=May 2008 He is now Emeritus Professor of Theoretical Computation at Queen Mary, University of London.

At a workshop in 2001 on the history of programming semantics [ [http://vmoc.museophile.org/pvs01/report.html Program Verification and Semantics: Report ] ] he spoke of how his scholarly career in Computer Science began in the late 1950s and of how he was much influenced by a study of McCarthy's LISP when the most commonly used language was Fortran.

He was active in the definition of the ALGOL programming language [listed amongst those who attended the November 1959 conference in Paris http://archive.computerhistory.org/resources/text/algol/algol_bulletin/A8/A8.HTM and the 1962 conference http://www.masswerk.at/algol60/report.htm ] [ P. J. Landin. A formal description of Algol 60. In Steel [Ste64] , pages 266-294. ] and cited by Tony Hoare as one of the people who taught him Algol 60 and hence facilitated his expression of powerful recursive algorithms:

"Around Easter 1961, a course on ALGOL 60 was offered in Brighton, England, with Peter Naur, Edsger W. Dijkstra, and Peter Landin as tutors. ... It was there that I first learned about recursive procedures and saw how to program the sorting method which I had earlier found such difficulty in explaining. It was there that I wrote the procedure, immodestly named QUICKSORT, on which my career as a computer scientist is founded. Due credit must be paid to the genius of the designers of ALGOL 60 who included recursion in their language and enabled me to describe my invention so elegantly to the world. I have regarded it as the highest goal of programming language design to enable good ideas to be elegantly expressed." [ACM Turing Award Lecture: The Emperor's Old Clothes. C. Antony R. Hoare 1980, Published in the Communications of the ACM ]

Landin is responsible for inventing the SECD machine and the ISWIM programming language, defining the Landin "off-side rule" and for coining the term "syntactic sugar". The off-side rule allows bounding scope declaration by use of white spaces as seen in languages such as Miranda, Haskell and Python.

Another phrase originating with Landin is "The next 700 …" after his influential paper "The next 700 programming languages" [cite journal
last = Landin
first = Peter J.
month = March
year = 1966
title = The next 700 programming languages
url = http://www.cs.utah.edu/~wilson/compilers/old/papers/p157-landin.pdf
journal = Communications of the ACM
volume = 9
issue = 3
pages = 157–166
doi = 10.1145/365230.365257] . "700" was chosen because Landin had read in the "Journal of the ACM" that there were already 700 programming languages in existence [Personal communication, September 2007.] . The paper opens with the quotation "... today... 1,700 special programming languages used to 'communicate' in over 700 application areas.". [Computer Software Issues, an American Mathematical Association Prospectus, July 1965] It also includes the joke that

"A possible first step in the research program is 1700 doctoral theses called "A Correspondence between x and Church's λ-notation"

a reference to his earlier paper ["A correspondence between ALGOL 60 and Church's Lambda-notation". Comm. ACM 8 (1965), 89-101; 158-165.] . This dry sense of humour is expressed in many of his papers.

Major 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.

References

External links

* [http://www.dcs.qmw.ac.uk/~peterl/ Landin's website]
*
* [http://vmoc.museophile.org/pvs01/ "Program Verification and Semantics: The Early Work"] meeting, 2001