P. America and F. de Boer. A sound and complete proof system for SPOOL. Technical Report Technical Report 505, Philips Research Laboratories, 1990.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....objects contained in others may be able to be referred to and sent messages from objects outside the container. The earliest approaches to managing the programs object graphs replaced references to objects with treestructured paths, which explicitly impose an ownership structure in the program [4, 8, 6], and require all accesses to the interior nodes of a tree to pass through the root of the tree. Introducing linear objects, which can be referred to only by a single pointer, can also enforce a tree structure upon the object graph [5, 28] Linear objects are accessed directly by pointers rather ....

P. America and F. de Boer. A sound and complete proof system for SPOOL. Technical Report Technical Report 505, Philips Research Laboratories, 1990.

....fails to do. None of the above approaches have been completely formalised, despite considerable effort. We have a sound formalisation and proven alias protection guarantees. Much work has been done in program language semantics in proposing means for coping with pointers and references including [27, 13, 41, 30, 21, 5, 8, 7, 46]. Special reference attachment mechanisms have been proposed for language run time systems to enforce unique or linear pointers [6, 11, 34, 20, 28] Unfortunately, these proposals forbid many common uses of aliasing in object oriented programs. A common approach to preventing representation ....

Pierre America and Frank de Boer. A sound and complete proof system for SPOOL. Technical Report Technical Report 505, Philips Research Laboratories, 1990.

.... can be analysed directly to detect possible aliasing [25, 11, 23] or hints may be given to the compiler as to probable aliasing invariants [19] Objects can be referred to by tracing paths through programs, rather than by direct pointers, so that aliased objects will always have the same name [2, 6, 5], or programs can be rewritten to explicitly restrict pointers to particular sets of objects [39] The refinement calculus has been extended to deal with programs with pointer structures, by including an explicit model of the local store together with hiding of the pointer implementation and ....

Pierre America and Frank de Boer. A sound and complete proof system for SPOOL. Technical Report Technical Report 505, Philips Research Laboratories, 1990.

....map. As such, it is difficult to see how one could reason about the local effect of such expressions using this semantics as a basis. Other work in this area includes the generalized object model of Hailpern and Nguyen [16] the Actor semantics by Agha [2] and the semantics of POOL, as found in [3, 4]. In the generalized object model, objects are modeled as CSP processes, and objects communicate via CSP ports. There is no decoupling of object data and methods, so local procedures are always in scope. Because of this, there is no need for a notion of self , in order to invoke local procedures. ....

P. America and F. de Boer. A sound and complete proof system for spool. Technical Report 505, Phillips Research Laboratories, May 1990. 30

....of the code components in isolation. The formalist must show that no predicate is affected by being effectively aliased with the left side of any assignment statement. Control is thus based on some analysis of state reachability. A proof system for an object oriented language (SPOOL) is given in [AdB90]. This uses aliasing control exclusively; there is no prevention component to the management strategy. The predicate language is an extension to the programming language in which encapsulation is removed. Within some context, variables in other objects can be referred to using variable paths as ....

Pierre America and Frank de Boer. A sound and complete proof system for SPOOL. Technical Report 505, Philips Research Laboratories, May 1990.

.... can be analysed directly to detect possible aliasing [26, 10, 22] or hints may be given to the compiler as to probable aliasing invariants [18] Objects can be referred to by tracing paths through programs, rather than by direct pointers, so that aliased objects will always have the same name [3, 6, 5], or pointers can be restricted to point to a particular set of objects [38] Copying, swapping, destructive reads, or destructive assignments can replace regular reference assignment in programs, so that each object is only referred to by one unique or linear pointer [4, 8, 32, 17, 27] Finally, ....

Pierre America and Frank de Boer. A sound and complete proof system for SPOOL. Technical Report Technical Report 505, Philips Research Laboratories, 1990.

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