Peter John Landin (5 June 1930 – 3 June 2009
) was a British
computer scientist
A computer scientist is a person who is trained in the academic study of computer science.
Computer scientists typically work on the theoretical side of computation, as opposed to the hardware side on which computer engineers mainly focus (a ...
. He was one of the first to realise that the
lambda calculus
Lambda calculus (also written as ''λ''-calculus) is a formal system in mathematical logic for expressing computation based on function abstraction and application using variable binding and substitution. It is a universal model of computation th ...
could be used to model a
programming language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language.
The description of a programming ...
, an insight that is essential to the development of both
functional programming
In computer science, functional programming is a programming paradigm where programs are constructed by applying and composing functions. It is a declarative programming paradigm in which function definitions are trees of expressions that ...
and
denotational semantics
In computer science, denotational semantics (initially known as mathematical semantics or Scott–Strachey semantics) is an approach of formalizing the meanings of programming languages by constructing mathematical objects (called ''denotations' ...
.
Academic
Landin was born in
Sheffield
Sheffield is a city in South Yorkshire, England, whose name derives from the River Sheaf which runs through it. The city serves as the administrative centre of the City of Sheffield. It is historically part of the West Riding of Yorkshire and ...
, where he attended
King Edward VII School; he graduated from
Clare College
Clare College is a constituent college of the University of Cambridge in Cambridge, England. The college was founded in 1326 as University Hall, making it the second-oldest surviving college of the University after Peterhouse. It was refounded ...
,
Cambridge University
, mottoeng = Literal: From here, light and sacred draughts.
Non literal: From this place, we gain enlightenment and precious knowledge.
, established =
, other_name = The Chancellor, Masters and Schola ...
.
From 1960 to 1964, he was the assistant to
Christopher Strachey
Christopher S. Strachey (; 16 November 1916 – 18 May 1975) was a British computer scientist. He was one of the founders of denotational semantics, and a pioneer in programming language design and computer time-sharing.F. J. Corbató, et al., T ...
when the latter was an independent computer consultant in
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a major s ...
. Most of his work was published during this period and the brief time he worked for
Univac
UNIVAC (Universal Automatic Computer) was a line of electronic digital stored-program computers starting with the products of the Eckert–Mauchly Computer Corporation. Later the name was applied to a division of the Remington Rand company an ...
and at the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
in the United States, before taking a position at
Queen Mary University of London
Queen Mary University of London (QMUL, or informally QM, and previously Queen Mary and Westfield College) is a public university, public research university in Mile End, East London, England. It is a member institution of the federal University of ...
. During the 1970s and 1980s, his efforts went into building the
computer science department in Queen Mary College, developing courses, and teaching students, as set forth in the foreword to the textbook ''Programming from First Principles''. On his retirement, he was appointed Emeritus Professor of
Theoretical Computation at
Queen Mary University of London
Queen Mary University of London (QMUL, or informally QM, and previously Queen Mary and Westfield College) is a public university, public research university in Mile End, East London, England. It is a member institution of the federal University of ...
, where in 2012, the computer science building was renamed the Peter Landin Building in his honour.
At a workshop at the
Science Museum
A science museum is a museum devoted primarily to science. Older science museums tended to concentrate on static displays of objects related to natural history, paleontology, geology, industry and industrial machinery, etc. Modern trends in mu ...
,
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a major s ...
, in 2001, on the history of
programming semantics 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
John McCarthy's
Lisp
A lisp is a speech impairment in which a person misarticulates sibilants (, , , , , , , ). These misarticulations often result in unclear speech.
Types
* A frontal lisp occurs when the tongue is placed anterior to the target. Interdental lisping ...
language when the most commonly used language was
Fortran.
He was active in the definition of the
ALGOL
ALGOL (; short for "Algorithmic Language") is a family of imperative computer programming languages originally developed in 1958. ALGOL heavily influenced many other languages and was the standard method for algorithm description used by the ...
programming language. He is listed among those who attended the November 1959 conference in
Paris
Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
, and the 1962 conference, and cited by
Tony Hoare
Sir Charles Antony Richard Hoare (Tony Hoare or C. A. R. Hoare) (born 11 January 1934) is a British computer scientist who has made foundational contributions to programming languages, algorithms, operating systems, formal verification, and c ...
as one of the people who taught him
ALGOL 60
ALGOL 60 (short for ''Algorithmic Language 1960'') is a member of the ALGOL family of computer programming languages. It followed on from ALGOL 58 which had introduced code blocks and the begin and end pairs for delimiting them, representing a ...
and hence facilitated his expression of powerful recursive algorithms:
Landin was involved with
international standard
international standard is a technical standard developed by one or more international standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization is the International Org ...
s in programming and informatics, as a member of the
International Federation for Information Processing
The International Federation for Information Processing (IFIP) is a global organisation for researchers and professionals working in the field of computing to conduct research, develop standards and promote information sharing.
Established in 19 ...
(IFIP)
IFIP Working Group 2.1 on Algorithmic Languages and Calculi, which
specified, maintains, and supports the
programming language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language.
The description of a programming ...
s
ALGOL 60
ALGOL 60 (short for ''Algorithmic Language 1960'') is a member of the ALGOL family of computer programming languages. It followed on from ALGOL 58 which had introduced code blocks and the begin and end pairs for delimiting them, representing a ...
and
ALGOL 68
ALGOL 68 (short for ''Algorithmic Language 1968'') is an imperative programming language that was conceived as a successor to the ALGOL 60 programming language, designed with the goal of a much wider scope of application and more rigorously de ...
.
Landin is responsible for inventing the ''stack, environment, control, dump''
SECD machine The SECD machine is a highly influential (''see: '') virtual machine and abstract machine intended as a target for functional programming language compilers. The letters stand for Stack, Environment, Control, Dump—the internal registers of the mac ...
, the first
abstract machine
An abstract machine is a computer science theoretical model that allows for a detailed and precise analysis of how a computer system functions. It is analogous to a mathematical function in that it receives inputs and produces outputs based on pr ...
for a
functional programming
In computer science, functional programming is a programming paradigm where programs are constructed by applying and composing functions. It is a declarative programming paradigm in which function definitions are trees of expressions that ...
language, and the
ISWIM
ISWIM (acronym for If you See What I Mean) is an abstract computer programming language (or a family of languages) devised by Peter Landin and first described in his article "The Next 700 Programming Languages", published in the Communications o ...
programming language, defining the Landin ''
off-side rule
A computer programming language is said to adhere to the off-side rule of syntax if blocks in that language are expressed by their indentation. The term was coined by Peter Landin, possibly as a pun on the offside rule in association footbal ...
'' and for coining the term ''
syntactic sugar
In computer science, syntactic sugar is syntax within a programming language that is designed to make things easier to read or to express. It makes the language "sweeter" for human use: things can be expressed more clearly, more concisely, or in a ...
''. The off-side rule allows bounding scope declaration by use of white spaces as seen in languages such as
Miranda,
Haskell
Haskell () is a general-purpose, statically-typed, purely functional programming language with type inference and lazy evaluation. Designed for teaching, research and industrial applications, Haskell has pioneered a number of programming lang ...
,
Python
Python may refer to:
Snakes
* Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia
** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia
* Python (mythology), a mythical serpent
Computing
* Python (pr ...
, and
F# (using the ''light'' syntax).
Another phrase originating with Landin is "The next 700 ..." after his influential paper ''The next 700 programming languages''. "700" was chosen because Landin had read in the ''
Journal of the ACM
The ''Journal of the ACM'' is a peer-reviewed scientific journal covering computer science in general, especially theoretical aspects. It is an official journal of the Association for Computing Machinery. Its current editor-in-chief is Venkatesan ...
'' that there were already 700 programming languages in existence. The paper opens with the quotation "... today ... 1,700 special programming languages used to 'communicate' in over 700 application areas." It also includes the joke that
a reference to his earlier paper. This dry sense of humour is expressed in many of his papers.
Political
Landin, who was bisexual,
became involved with the
Gay Liberation Front
Gay Liberation Front (GLF) was the name of several gay liberation groups, the first of which was formed in New York City in 1969, immediately after the Stonewall riots. Similar organizations also formed in the UK and Canada. The GLF provided a v ...
(GLF) during the early 1970s. He was once arrested as part of an anti-nuclear demonstration.
He was a dedicated cyclist and moved around London on his bike until it became physically impossible for him to do so.
Legacy
The
Bodleian Library
The Bodleian Library () is the main research library of the University of Oxford, and is one of the oldest libraries in Europe. It derives its name from its founder, Sir Thomas Bodley. With over 13 million printed items, it is the second ...
in
Oxford
Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the ...
holds an archive of material relating to Peter Landin. Since 2010, there has been an ''Annual Peter Landin Semantics Seminar'' held annually each December in memory of Peter Landin and organized by the
BCS-FACS Specialist Group on Formal Aspects of Computing Science. The first seminar was delivered by the American computer scientist
John C. Reynolds (1935–2013). There is a Peter Landin Building at
Queen Mary University of London
Queen Mary University of London (QMUL, or informally QM, and previously Queen Mary and Westfield College) is a public university, public research university in Mile End, East London, England. It is a member institution of the federal University of ...
housing teaching and research facilities for
computer science.
Selected publications
*
*
*
* Reprinted in
*
*
See also
*
J operator
Notes
Sources
*
*
External links
*
* , BCS
Computer Conservation Society
The Computer Conservation Society (CCS) is a British organisation, founded in 1989. It is under the joint umbrella of the British Computer Society (BCS), the London Science Museum and the Manchester Museum of Science and Industry.
Overview
The ...
seminar,
Science Museum
A science museum is a museum devoted primarily to science. Older science museums tended to concentrate on static displays of objects related to natural history, paleontology, geology, industry and industrial machinery, etc. Modern trends in mu ...
, London, UK, 5 June 2001
Memorial talkon Landin's life by
Olivier Danvy
Olivier Danvy is a French computer scientist specializing in programming languages, partial evaluation, and continuations. He is a professor at Yale-NUS College in Singapore.
Danvy received his PhD degree from the Université Paris VI in 198 ...
at
ICFP 2009
Peter Landin's talkat ''Program Verification and Semantics: The Early Work'', 2001 (video)
{{DEFAULTSORT:Landin, Peter
1930 births
2009 deaths
People educated at King Edward VII School, Sheffield
Alumni of Clare College, Cambridge
English computer scientists
Programming language researchers
Formal methods people
Massachusetts Institute of Technology faculty
Academics of Queen Mary University of London
Bisexual men
Bisexual scientists
English LGBT people
LGBT scientists from the United Kingdom
British anti–nuclear weapons activists
LGBT rights activists from England
Bisexual academics
20th-century LGBT people