He is best known for designing and implementing three programming languages, including the first for functional programming based on lazy evaluation, combinator graph reduction, and polymorphic types: SASL (1972), Kent Recursive Calculator (KRC) (1981), and the commercially supported Miranda (1985).
[1] Turner first implemented SASL using the abstract SECD machine, but then reimplemented them in 1978 using SKI combinator calculus.
[2] This approach was used by Thomas Johnsson and Lennart Augustsson in the design of the g-machine[3] that evolved to become the standard mechanism for lazy evaluation in call-by-need languages.
Turner was involved with developing international standards in programming and informatics, as a member of the International Federation for Information Processing (IFIP) IFIP Working Group 2.1 on Algorithmic Languages and Calculi,[7] which specified, maintains, and supports the programming languages ALGOL 60 and ALGOL 68.
[8] He was also a member of the IFIP Working Group 2.8 on Functional Programming, which related to his creation of Miranda.