Absys was an early declarative programming language from the University of Aberdeen. It anticipated a number of features of Prolog such as negation as failure, aggregation operators, the central role of backtracking and constraint solving. Absys was the first implementation of a logic programming language.
The name Absys was chosen as an abbreviation for Aberdeen System.
- Elcock, E.W. (1990). "Absys: the first logic programming language —A retrospective and a commentary". The Journal of Logic Programming. 9 (1): 1–17. doi:10.1016/0743-1066(90)90030-9.
- Kowalski, R. A. (1988). "The early years of logic programming" (PDF). Communications of the ACM. 31: 38. doi:10.1145/35043.35046.
- "ABSYS: An Incremental Compiler for Assertions", J.M. Foster et al., Mach Intell 4, Edinburgh U Press, 1969, pp. 423–429