BCS FACS - Annual Peter Landin Semantics Seminar 2014

On correspondences between programming languages and semantic notations

Date/Time: Monday 8 December 2014, 6.00pm - 8.30pm

BCS, First Floor, The Davidson Building, 5 Southampton Street, London, WC2E 7HA

Cost to attend: Free of charge, but, please book your place via the BCS online booking system.

Speaker: Prof. Peter Mosses, Swansea University


Peter Landin (1930 - 2009) was a pioneer whose ideas underpin modern computing. In the the 1950s and 1960s, Landin showed that programs could be defined in terms of mathematical functions, translated into functional expressions in the lambda calculus, and their meaning calculated with an abstract mathematical machine. Compiler writers and designers of modern-day programming languages alike owe much to Landin's pioneering work.

Each year, a leading figure in computer science will pay tribute to Landin's contribution to computing through a public seminar. This year's seminar is entitled "On correspondences between programming languages and semantic notations" and will be given by Prof. Peter Mosses (Swansea University).


5.15pm Coffee
6.00pm Welcome & Introduction - Prof Tony Clark (Middlesex University)
6.05pm Peter Landin Semantics Seminar -
On correspondences between programming languages & semanic notations - Prof. Peter Mosses (Swansea University)
7.20pm Drinks Reception


Seminar details:

50 years ago, at the IFIP Working Conference on Formal Language Description Languages, Peter Landin presented a paper on “A formal description of ALGOL 60”. In it, he explained “a correspondence between certain features of current programming languages and a modified form of Church’s λ-notation”, and suggested using that as the basis for formal semantics. He regarded his formal description of ALGOL 60 as a “compiler” from ALGOL abstract syntax to λ-notation.

10 years later, denotational semantics was well established, and two denotational descriptions of ALGOL 60 had been produced as case studies: one in the VDM style developed at IBM-Vienna, the other in the continuations-based style adopted in Christopher Strachey’s Programming Research Group at Oxford.

After recalling Landin’s approach, I’ll illustrate how it differs from denotational semantics, based on the ALGOL 60 descriptions. I’ll also present a recently developed component-based semantics for ALGOL 60, involving its translation to an open-ended collection of so-called fundamental constructs. I’ll assume familiarity with the main concepts of denotational semantics.