Amal J. Ahmed, Andrew W. Appel, and Roberto Virga. A stratified semantics of general references embeddable in higher-order logic. In Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....i,thelevelof# in the type hierarchy, i must be part of the Godel number for ref(#, #) note that ref(#, #) is at level i 1in this hierarchy) rep(i 1, tree 2 (3, tree 0 (i) n) ref(#, #) n i 4. rep(i) rep(i 1) rep(i 1,n,#) We show the inductive definition in the technical report [3]. Figure 2 illustrates the first few levels of the hierarchy for the pretype constructors int, Level 0 consists of the Godel numberings of int, int int, int int) int,and so on. Let # denote a pretype that has a Godel number at level 0. Level 1 consists of Godel numberings of ....

....F ) k, a, m,x) F k 1 (box(#, #) k,a, m,x) #n. x, n) #(n, K const(m(x) #(n, K#n ) #n = # (codeptr(#, #) k,a, m,x) #r # ,a # ,m # ,j.j k r # (PC) x #,j (a # ,m # ) #(j, a # ,m # ,r # (1) safen(j, r # ,m # ) Figure 3. Pretype definitions technical report [3] contains a more detailed exposition of our model (including existential and universal types which we have not described here due to lack of space) as well as proofs of the theorems in this paper. 7.1 Godel numbers of pretype functions Our model requires that we specify the Godel number of each ....

[Article contains additional citation context not shown here]

A. J. Ahmed, A. W. Appel, and R. Virga. A stratified semantics of general references embeddable in higher-order logic. Technical Report TR-650-02, Princeton University, May 2002.

....steps with each type being defined as a complex set of indexed values. More seriously, none of these approaches can be easily extended to support mutable fields and higher order polymorphism. In fact, the only known solution to mutable fields was only proposed very recently by Ahmed et al. [2] the proposal involves building a hierarchy of Godel numberings and making extensive changes to semantic models used in existing FPCC systems [5, 6] In this article, we present a syntactic approach to FPCC that avoids all of these di#culties. Under our new scheme, the foundational proof for a ....

.... a type checker while the syntactic soundness proof is known to be much easier to construct than the semantic soundness proof [25] Our article makes the following new contributions: Foundational proofs are widely perceived as extremely hard and tedious to construct, partly because existing e#orts [5, 9, 1, 6, 2, 21] on FPCC have all adopted the semantic approach (which requires building sophisticated models from first principles) We show that this perception is not true: with a syntactic approach, constructing foundational proofs is much simpler and more straightforward. As far as we know, our work is ....

[Article contains additional citation context not shown here]

A. J. Ahmed, A. W. Appel, and R. Virga. A stratified semantics of general references embeddable in higher-order logic (extended abstract). In Proc. 17th IEEE Annual Symposium on Logic in Computer Science, page (to appear), July 2002.

....the proofs but still involves tedious reasoning of computation steps. More seriously, none of these approaches can be easily extended to support mutable fields and higher order polymorphism. In fact, the only known solution to mutable fields was proposed only very recently by Ahmed et al. [2] the proposal involves building a hierarchy of Godel numberings and making extensive changes to semantic models used in existing FPCC systems [4, 5] In this paper, we present a syntactic approach to FPCC that avoids all of these difficulties. Under our new scheme, the foundational proof for a ....

.... type checker while the syntactic soundness proof is known to be much easier to construct than the semantic soundness proof [24] Our paper makes the following new contributions: Foundational proofs are widely perceived as extremely hard and tedious to construct, partly because existing efforts [4, 8, 1, 5, 2, 21] on FPCC have all adopted the semantic approach (which requires building sophisticated models from first principles) We show that this perception is not true: with a syntactic approach, constructing foundational proofs is much simpler and more straightforward. As far as we know, our work is ....

[Article contains additional citation context not shown here]

A. J. Ahmed, A. W. Appel, and R. Virga. A stratified semantics of general references embeddable in higher-order logic (extended abstract). In Proc. 17th IEEE Annual Symposium on Logic in Computer Science, page (to appear), July 2002.

No context found.

Amal J. Ahmed, Andrew W. Appel, and Roberto Virga. A stratified semantics of general references embeddable in higher-order logic. In In Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002.

No context found.

Ahmed, A., Appel, A.W., Virga, R.: A stratified semantics of general references embeddable in higher-order logic. In: 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002). (2002) 75--86

No context found.

Amal Ahmed, Andrew W. Appel, and Roberto Virga. A stratified semantics of general references embeddable in higher-order logic. In IEEE Symposium on Logic in Computer Science (LICS), Copenhagen, Denmark, pages 75--86, July 2002.

No context found.

A. Ahmed, A. W. Appel, and R. Virga. A stratified semantics of general references embeddable in higher-order logic. In 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002.

No context found.

Ahmed, A., Appel, A.W., Virga, R.: A stratified semantics of general references embeddable in higher-order logic. In: 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002). (2002) 75--86

No context found.

A. Ahmed, A. W. Appel, and R. Virga. A stratified semantics of general references embeddable in higher-order logic. In 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002.

No context found.

A. Ahmed, A. W. Appel, and R. Virga. A stratified semantics of general references embeddable in higher-order logic. In 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002.

No context found.

Amal J. Ahmed, Andrew W. Appel, and Roberto Virga. A stratified semantics of general references embeddable in higher-order logic. In In Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002.

.... move the type system out of the TCB, and model machine instructions by a step relation between machine states; we avoid VCGen entirely [3] In order to support contravariant recursive datatypes and mutable fields, we model types as predicates on states, approximation indices [4] and type levels [1]. We have an abstraction layer, Typed Machine Language (TML) 20] to hide the complex semantic models for types. TML provides a rich set of constructors for types, type maps, and instructions, and an orthogonal set of primitive type constructors such as union, intersection, existential and ....

....be added to LTAL (and proved sound) without disturbing the soundess proofs for existing operators, as long as the new operators conform to the assumptions in the semantic model. We started with a very simple model [3] and when we added contravariant recursive types [4] and mutable record fields [1] these changes did violate previous assumptions and require nonmodular rewrites. But now our model is very powerful and general: none of the existing LTAL soundness proofs will need to be touched when we add operators to handle extensible sums, various kinds of exception handling mechanisms, ....

[Article contains additional citation context not shown here]

Amal J. Ahmed, Andrew W. Appel, and Roberto Virga. A stratified semantics of general references embeddable in higher-order logic. In 17th Annual 10 IEEE Symposium on Logic in Computer Science (LICS 2002.

No context found.

Amal J. Ahmed, Andrew W. Appel, and Roberto Virga. A stratified semantics of general references embeddable in higher-order logic. In Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002.

No context found.

Amal J. Ahmed, Andrew W. Appel, and Roberto Virga. A stratified semantics of general references embeddable in higher-order logic. In Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science (LICS 2002.

No context found.

Amal J. Ahmed, Andrew W. Appel, and Roberto Virga. A stratified semantics of general references embeddable in higher-order logic. In Proceedings of the 17th Annual IEEE Symposium on Logic in Computer Science (LICS '02), pages 75--86. IEEE Computer Society, July 2002.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC