Berry, Daniel M. Block structure: Retention or deletion. In Proceedings of the Third Annual ACM Symposium on Theory of Computing (1972) 86--100.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....storage of all variables (other than own variables) 8, 29] Storage is created on the stack when control enters a block and is discarded upon exit. This is sometimes called the deletion strategy , as the values of the local variables are deleted upon exit from the block as the stack is popped [2]. ALGOL 60 provides no way for these variables subsequently to be referenced, so the deleted variables are no longer needed, and hence, the stack implementation is correct for that language [12] Other languages such as LISP [21] PAL [9] OREGANO [1] etc. do provide ways in which variables ....

....procedure may be referenced from outside, so their bindings must be retained; hence the name retention strategy . Berry has shown that the copy rule of ALGOL, when extended in a natural way to these more powerful languages, is equivalent to the retention strategy and not to the deletion strategy [2]. The retention strategy, then, is seemingly more powerful than the deletion strategy. However, we show in this paper that the classes of programs corresponding to the two strategies are equivalent in a very strong sense for every retention strategy program, we can find an equivalent program ....

Berry, Daniel M. Block structure: Retention or deletion. In Proceedings of the Third Annual ACM Symposium on Theory of Computing (1972) 86--100.

....and as in Section 3, our representation of # embodies its LIFO nature without committing to an actual representation. This representation can be retentive (in which case # is implemented as a pointer into the heap) or destructive (in which case # is implemented as, e.g. a rewriteable array) [3]. In both cases, swap# is implemented as copying #. Copying the pointer yields captured continuations to be shared and copying the array yields multiple representations of captured continuations. 5 A segmented stack machine for first class continuations Coroutines and threads are easily simulated ....

Daniel M. Berry. Block structure: Retention or deletion? (extended abstract). In Conference Record of the Third Annual ACM Symposium on Theory of Computing, pages 86--100, Shaker Heights, Ohio, May 1971.

....a given program. Morcm or. flcrc is a correspondence between computational states that each machine goes through. 72 EQUIVAI.ENCE OF L1 AND L2 4. 1 We shall use an adaptation of the McGowan mapping technique for proving the equivalence of two machines[25] A similar technique was used by Berry [6] to prove the equivalence of two information structure models of block structured languages. Let P be a program in the base language. Schematically, the computation of P on L1 and L2 is shown in the Figure 18. A computation is a sequence of states starting with some initial state; if the ....

Berry, Daniel M. Block Structure: Retention or Deletion. Proc. of the Third Annual Symposium on the Theory of Computing, May, 1971.

....All objects are created in a local heap. In Figure 3, the object representing the string tadpole will be unreachable long before it gains any rights to long term persistence. In fact, many Napier objects are short lived; this is exacerbated by the fact that Napier is a block retention language [9] and that activation records are allocated by the PAM from the heap rather than from a stack. If transient objects are confined to a localised area, they may be distinguished from persistent objects resident in the total persistent address space and consequently garbage collected locally at low ....

Berry D.M. "Block Structure: Retention or Deletion?". Conference Record of the Third Annual ACM Symposium on the Theory of Computing, Shakes Heights, Ohio, pp. 86-100 (May 1971).

....be local to j. To this end, we define the binary relation Index (read is local to ) as follows. hi 1 ; i 2 i Index hj 1 ; j 2 i , def i 1 j 1 (i 1 = j 1 i 2 j 2 ) This relation could be refined by considering relative lexical positions in the same block, and otherwise is traditional [3]. 2.7 Valuation functions The main valuation functions are displayed in Figure 2. The other ones are shown in appendix. 3 A Definitional Interpreter and its Residualization We have transcribed the denotational specification of Section 2 into a definitional interpreter which is compositional and ....

Daniel M. Berry. Block structure: Retention or deletion? (extended abstract). In Conference Record of the Third Annual ACM Symposium on Theory of Computing, pages 86--100, Shaker Heights, Ohio, May 1971.

.... 70] provide the first example of a group of interpreter equivalence proofs which establish an equivalence class of significantly different, practically important interpreters [Wegner 72a] McGowan [McGowan 71] proves the equivalence of three interpreters for lambda calculus and Berry [Berry 71] proves the equivalence of two models of block structure semantics. McGowan [McGowan 72] outlines a theory of interpreter equivalence theorems very similar to those we discussed in chapter 2. These writers also recognized the applicability of these proof techniques to compilers. The first attempt ....

D.M. Berry. Block Structure: Retention or Deletion? In 3rd SIGACT Symposium on the Theory of Computing. 1971.

....model as an alternative to the stack model [63] The idea is that a cell is deallocated only when it is no longer accessible in all execution traces. Thus a variable declared within an inner block can be referenced outside it, so that its binding must be alive when the block finishes. Berry [15] termed this the retention strategy, in contrast to the deletion strategy espoused by the stack model. In [15] Berry also proved the correctness of Algol 60 s copy rule with respect to the retention strategy. This allowed him to develop the language Oregano [16] where block structuring supported ....

....no longer accessible in all execution traces. Thus a variable declared within an inner block can be referenced outside it, so that its binding must be alive when the block finishes. Berry [15] termed this the retention strategy, in contrast to the deletion strategy espoused by the stack model. In [15], Berry also proved the correctness of Algol 60 s copy rule with respect to the retention strategy. This allowed him to develop the language Oregano [16] where block structuring supported the retention strategy. Oregano was considered to be a generalization of Algol 60 with labels and (recursive) ....

Berry, D. M. Block structure: retention or deletion? In Conference Record of Third Annual ACM Symposium on Theory of Computing (1971), pp. 86--100.

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