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A Plea for Grey-Box Components

Martin Büchi
Turku Centre for Computer Science
Lemminkäisenkatu 14A, FIN-20520 Turku, Finland
Martin.Buechi@abo.fi, http://www.abo.fi/~mbuechi/
phone: +358 2 265 4033, fax: +358 2 241 0154

Wolfgang Weck
Turku Centre for Computer Science
Lemminkäisenkatu 14A, FIN-20520 Turku, Finland
Wolfgang.Weck@abo.fi, http://www.abo.fi/~wweck/
phone: +358 2 265 4673, fax: +358 2 265 4732

August 29, 1997

Abstract:

Interface Description Languages (IDLs) describe the syntactic part of a component's interface, but they do not help to specify semantics. Additional informal descriptions or pre- and postconditions of operations are often not precise enough. For instance, they cannot properly describe call-back scenarios, that is, the states, at which external calls are made, and the sequence of calls. Revealing the full implementation, that is, the source code, on the other hand, overspecifies the component and, thus, prohibits alternative implementations and future enhancements. What is needed is a language that allows to reveal as much of an implementation as is required to use a component, but not more.

Such a language can be found in the theory of program refinement, but this is rarely used with commercial software because of the human factor: the notation is very symbolic instead of resembling a known implementation language. The lack of tool support for simulating specifications and for automatic refinement proofs also limits the enticement of writing specifications.



Keywords: Semantic specification of components, grey-box components, IDLs, component specification languages, abstract statements



Workshop Goals: Exchange of ideas, getting feedback on approach, make new contacts


 
next up previous
Next: 1 Introduction & Background Up: FoCBS

Martin Buechi and Wolfgang Weck
Sept. 2, 1997