Ravara, A. and Vasconcelos, V. T. 2000. Typing Non-uniform Concurrent Objects. In CONCUR '00. LNCS, vol. 1877. Springer, Berlin, 474-488.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....system where messages are dispatched to a certain object if and only if it provides the method invoked in the request, and it is ready to execute it. An accomplished solution is the semantics of Vasconcelos and Tokoro s calculus of objects [31] upon which the TyCO programming language is based [30,26]. The first problem requires interaction to take place only if both customer and service provider agree on a set of service parameters. The second one requires the message and the recipient to agree on object identity and method. Both problems can be generalised as instances of the problem of ....

Ravara, A. and V. T. Vasconcelos, Typing non-uniform concurrent objects, in: CONCUR'00, LNCS 1877, Springer-Verlag, 2000 pp. 474--488.

....behaviour, by allowing objects method suites to be determined at object creation time. Self [2] allows dynamic inheritance among prototypes, thus making type inference dicult [3] In BETA [23] nested patterns model dynamic state changes, but require dynamic type checking. For concurrent objects [25] gives behavioural types that guarantee that every message has a chance of being received if it requires a method that may be enabled at some point in the future. Fickle is the successor of our earlier proposal, Fickle 99 [13] which addressed the same requirement. Fickle improves Fickle 99 in at ....

A. Ravara and V.T. Vasconcelos. Typing non-uniform concurrent objects. In CONCUR'00, volume 1877 of LNCS, pages 474-488. Springer, 2000.

....of 1 j 2 , thereby alleviating state explosion. Indeed, if the program subjected to type checking is well modularized, this may save an exponential amount of work. 5 Related Work Several behavioral type systems have been proposed recently in which types are process like structures, including [18, 22, 19, 21, 11]. Also, other analyses have been proposed to check behavioral properties of concurrent programs, including [8, 9, 7] Our work was foremostly inspired by the generic type system of Igarashi and Kobayashi [11] While Igarashi and Kobayashi use a free fragment of CCS for their process types, our ....

A. Ravara and V. Vasconcelos. Typing non-uniform concurrent objects. In CONCUR 00: Concurrency Theory, LNCS 1877, pages 474-488. Springer-Verlag, 2000.

....our works on Erlang ( ARM 96] because it requires more precise type. 5.2. Related work Many different studies are currently related to the static analysis of non uniform service availability. Following lines proposed by Nierstrasz [NIE 95] Puntigam ( PUN 96] Ravara and Vasconcelos ( RAV 97, RAV 99] and Najm and Nimour [NAJ 97, NAJ 99] propose the use of more sophisticated type abstractions (in fact, the structure of their types is a process calculus) Their work is very promising as their abstractions preserve more causal relations. However, their type systems rely on explicit typing ....

RAVARA A., VASCONCELOS V., "Typing non-uniform concurrent objects", report num. 1049-001, 1999, Sect. Computer Science, Dept. Mathematics, Inst. Sup. Tcnico.

.... ] if (n 6= n 0 ) then Errorhi else Receiverhc; n 1)i main( a : ch(num) b : ch) c : ch) b : c j Sender hc; a; 0i) j Sender hbi j Receiver ha; 0i Figure 19: CCS types for the webserver 7 Related Work Behavioral types have received much attention in recent work, including [11, 17, 22, 23, 25, 28, 9, 10, 16]. The core rules of our type system are inspired by two previous lines of work. One is the e ect type system for the calculus by Gordon and Je rey [11] and the other is the generic type system for the calculus by Igarashi and Kobayashi [17] A novel feature of our system in comparison to [11] ....

A. Ravara and V. Vasconcelos. Typing non-uniform concurrent objects. In CONCUR 00: Concurrency Theory, LNCS 1877, pages 474-488. Springer-Verlag, 2000.

....right method for the message. Traditional type systems assign rigid interface like types to the names of the objects [13, 18, 6] Type systems that support objects with non uniform interfaces, based on the distinct de nition of a run time protocol error discussed above, have been proposed for TyCO [15, 16]. The systems ensure safety properties resulting from the absence of persistent bad redexes, namely the absence of some deadlocks (that we call local) and the guarantee that typable processes will not run into communication errors. Take the typical example of a one place bu er that only allows ....

Antonio Ravara and Vasco T. Vasconcelos. Typing Non-uniform Concurrent Objects. Submitted for publication, 1999.

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Antonio Ravara. Typing non-uniform concurrent objects. PhD thesis, Technical University of Lisbon, Portugal, 2000.

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A. Ravara and V. T. Vasconcelos. Typing non-uniform concurrent objects. In CONCUR '00: Proceedings of the International Conference on Concurrency Theory, volume 1877 of Lecture Notes in Computer Science, pages 474--488. Springer-Verlag, 2000.

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Antonio Ravara and Vasco T. Vasconcelos. Typing non-uniform concurrent objects. Research report 6/00 DM-IST, Technical University of Lisbon.

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Antonio Ravara. Typing non-uniform concurrent objects. PhD thesis, Technical University of Lisbon, Portugal, 2000.

....with session types, an object containing a channel which its methods can use. The session type of the channel would constrain the use of the methods, perhaps imposing a particular sequence of method calls. This opens up the possibility of a connection with type systems for non uniform objects [10]: maybe a nonuniform object type could be generated by the session type of a hidden channel. If we add objects to our language then it will also be interesting to investigate how the existing theory of subtyping for session types [3] relates to subclasses and inheritance. Our language has no ....

A. Ravara and V. T. Vasconcelos. Typing non-uniform concurrent objects. In CONCUR'00, volume 1877 of LNCS, pages 474--488. Springer-Verlag, 2000.

No context found.

Ravara, A.: Typing non-uniform concurrent objects, Ph.D. Thesis, Technical University of Lisbon, Portugal, 2000.

....states that services may be refined as long as the original promises are still upheld . Despite having developed a calculus of objects, Nierstrasz did not apply these ideas in a type system for it, neither did he show how to model non uniform objects. This task has be taken by several authors [Bou98, Col97, CPS97, CPDS99, NN97, NNS99b, Pun96, Pun97, Pun99, RL99, RV00]. Some of these works propose a specific calculus and develop a particular language of types for that calculus to guarantee some envisaged property. The aim of this work is to study the semantic foundations of types for concurrent objects, using the tools and the body of knowledge of the theory ....

....no completeness results were obtained. The developments presented here are part of the first author s PhD thesis [Rav00] We use ABT to type non uniform concurrent objects in T yCO, where we formalise a notion of process with a communication error that copes with non uniform service availability [RV00]: we advocate that the right notion of communication error in systems of 39 concurrent objects is that no message should be forever not understood. Using ABT as the language of types, we have developed for T yCO a static type system that assigns terms of ABT to T yCO processes, and enjoys the ....

[Article contains additional citation context not shown here]

Antonio Ravara and Vasco T. Vasconcelos. Typing non-uniform concurrent objects. In Catuscia Palamidessi, editor, CONCUR 2000: Concurrency Theory (11th International Conference, University Park, PA, USA), volume 1877 of Lecture Notes in Computer Science, pages 474--488. Springer-Verlag, 2000. Extended version available as DM-IST Research Report 12/2000, Portugal. 44

....external silent actions and label (semi )strong bisimulation, appeared first in [RRV98] where however the algebra was much less tractable (e.g. with non associative sums) and no completeness results were obtained. The developments presented here are part of the first author s PhD thesis [Rav00]. We use ABT to type non uniform concurrent objects in T yCO, where we formalise a notion of process with a communication error that copes with non uniform service availability [RV00] we advocate that the right notion of communication error in systems of 39 concurrent objects is that no message ....

....should be forever not understood. Using ABT as the language of types, we have developed for T yCO a static type system that assigns terms of ABT to T yCO processes, and enjoys the subject reduction property, ensuring that typable processes are not locally deadlocked, and do not run into errors [RV00, Rav00]. We believe that ABT can be use not only to type other concurrent calculi with extensions for objects, but also to type calculi with localities. To fully use its expressiveness one can define in its favourite calculus functionalities like a method update that changes the type of the method, ....

Antonio Ravara. Typing Non-Uniform Concurrent Objects. PhD thesis, Instituto Superior Tecnico, Technical University of Lisbon, Portugal, 2000.

....and feels unnatural. However, the code may be simpler and clearer adopting a behaviour oriented style of programming like in non uniform objects objects that may dynamically change their behaviour and even the methods they offer as advocated by Nierstrasz [10] and studied by Ravara [12]. Related work. As mentioned in the introduction, several authors have provided a number of proposals that try to overcome the limitations that current component IDLs present, defining extensions that cope with the semantic aspects of object interfaces and behavior. Apart from those that try to ....

Ravara, A.: Typing non-uniform concurrent objects, Ph.D. Thesis, Technical University of Lisbon, Portugal, 2000.

....which we refer to as V a , but imposing a more restrictive type discipline. Indeed, as we may show formally, TyCO represents a proper subcalculus of V a . The obvious question arises, whether this subcalculus is less expressive. Ultimately, however, we are interested in non uniform TyCO [RL99, RV00, Rav], proposed by Ravara, which admits that objects may change their interface over time. It is instructive to try to understand the idea of non uniformity in TyCO by means of its standard calculus counterpart. The interesting point is that this way of explanation does not work. Nonuniformity in ....

A. Ravara and V. T. Vasconcelos. Typing Non-Uniform Concurrent Objects. In Proceedings of CONCUR 2000, LNCS. Springer, 2000. To appear.

....method for the message. Traditional type systems assign rigid interface like types to the names of the objects [6, 13, 18] Type systems that support objects with non uniform interfaces, based on the distinct de nition of a run time protocol error discussed above, have been proposed for TyCO [15, 16]. The systems ensure safety properties resulting from the absence of persistent bad redexes, namely the absence of some deadlocks (that we call local) and the guarantee that typable processes will not run into communication errors. Take the typical example of a one place bu er that only allows ....

Antonio Ravara and Vasco T. Vasconcelos. Typing Non-uniform Concurrent Objects. Submitted for publication, 1999.

....of types for non uniform concurrent objects. In particular, we discuss on a notion of equivalence and study its algebraic properties. The use of ABT as syntactic types for a calculus of concurrent objects, with a static type system enjoying the subject reduction property, is already in progress [22]. We build ABT gradually. Section 2 presents finite types, with a non deterministic labelled sum and a blocking operator, defines the operational semantics, an equivalence notion, and a complete axiomatisation for that equivalence. In Section 3 we add a parallel composition operator that is a ....

....was much less tractable (e.g. with non associative sums) and no completeness results were obtained. We are currently using ABT to type non uniform concurrent objects in T yCO, where we formalise a notion of process with a communication error that copes with non uniform service availability [22]. The type system assigns terms of the type algebra to processes, and ensures that typable processes are not locally deadlocked, and do not run into errors. We believe that ABT can be use to type other concurrent calculi with extensions for objects, but also to type calculi with localities. To ....

Antonio Ravara and Vasco T. Vasconcelos. Typing non-uniform concurrent objects. Research report, Department of Mathematics, Instituto Superior Tecnico, Av. Rovisco Pais 1096 Lisboa, Portugal, 1999.

No context found.

Ravara, A. and Vasconcelos, V. T. 2000. Typing Non-uniform Concurrent Objects. In CONCUR '00. LNCS, vol. 1877. Springer, Berlin, 474-488.

No context found.

Antnio Ravara and Vasco T. Vasconelos. Typing non-uniform concurrent objects. In Proceedings of the International Conference on Concurrency Theory, volume 1877 of LNCS, 2000.

No context found.

A. Ravara and V. Vasconcelos. Typing non-uniform concurrent objects. In Proceedings of CONCUR2000.

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A. Ravara and V. Vasconcelos. Typing non-uniform concurrent objects. In Proceedings of CONCUR2000.

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