TASK: from the specification to the implementation

The paper presents the TASK framework which is intended to cover the life cycle of a knowledge based system. TASK provides: (i) a conceptual language which enables an informal specification at the knowledge level; (ii) a formal language TFL which permits an unambiguous specification; and (iii) an operational shell TASK⁺ which allows an efficient execution even for badly structured problems. The paper presents the different languages, the links between them and emphasizes the implementation stage. We show how TASK proposes a nice compromise solution between efficiency and expressivity.