Editing Claire (programming language) (section)

==Overview==
Claire is a [[general-purpose programming language]], best suited to [[application software]] requiring sophisticated [[data modeling]], rule processing or problem solving. WebClaire adds extensions for fuller integration with the [[operating system]] and for programming [[web application]]s.

Though Claire can be used for complete projects, it is designed to integrate smoothly with [[C++]], [[Java (programming language)|Java]], or [[Go (programming language)|Go]].

The key set of features that distinguishes Claire from other programming languages has been dictated by experience in solving complex optimization problems. Two features not found in other mixed functional/object-oriented languages, such as [[OCaml]], [[Scala (programming language)|Scala]] and [[F Sharp (programming language)|F#]], are ''versioning'' and ''production rules''.

Versions can be viewed as a stack of snapshots of some part of the system, which can be made as large (for expressiveness) or small (for efficiency) as necessary. Creation and roll-back of versions permit [[backtracking]], as found in [[logic programming]], though Claire's backtracking may cover any user-defined structure rather than just a set of logic variables.

A production rule in Claire is composed of an event, a condition and a response to be evaluated if the condition is satisfied. An event may be any change in an object's slot or the instantiation of a class, and a response may itself set off further events. Such production rules are especially useful in describing reactive algorithms, such as those for [[Constraint programming|constraint]] propagation.

Claire was created as a successor to LAURE, an expressive but complex language designed by Caseau in the 1980s that combined many paradigms. Claire was intended to be both easier to learn than its predecessor and to impose no performance overhead relative to C++; it is thus a much smaller language, omitting features such as [[Constraint satisfaction|constraints]] and [[Deductive language|deductive]] rules, and is closer to [[C (programming language)|C]] in spirit and syntax. Its main users in industry have been the [[Bouygues]] and [[Thales Group]]s. The new Claire 4 release brings gains in reliability (via Go's strength as underlying language) and in performance of [[compiler]] and [[Interpreter (computing)|interpreter]].