Absys was an early declarative

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 ...

from the

University of Aberdeen The University of Aberdeen ( sco, University o' 'Aiberdeen; abbreviated as ''Aberd.'' in List of post-nominal letters (United Kingdom), post-nominals; gd, Oilthigh Obar Dheathain) is a public university, public research university in Aberdeen, Sc ...

. It anticipated a number of features of

Prolog Prolog is a logic programming language associated with artificial intelligence and computational linguistics. Prolog has its roots in first-order logic, a formal logic, and unlike many other programming languages, Prolog is intended primarily ...

such as

negation as failure Negation as failure (NAF, for short) is a non-monotonic inference rule in logic programming, used to derive \mathrm~p (i.e. that ~p is assumed not to hold) from failure to derive ~p. Note that \mathrm ~p can be different from the statement \neg p ...

, aggregation operators, the central role of backtracking and constraint solving. Absys was the first implementation of a

logic programming language Logic programming is a programming paradigm which is largely based on formal logic. Any program written in a logic programming language is a set of sentences in logical form, expressing facts and rules about some problem domain. Major logic prog ...

. The name ''Absys'' was chosen as an abbreviation for ''Aberdeen System''.

References

*"ABSYS: An Incremental Compiler for Assertions", J.M. Foster et al., Mach Intell 4, Edinburgh U Press, 1969, pp. 423–429 {{DEFAULTSORT:Absys Declarative programming languages Prolog programming language family Academic programming languages Logic programming languages Programming languages created in 1967

See also

References