The Kestrel Interactive Development System (KIDS) provides automated sup- port for the development of correct and efficient programs from formal specifications.

The Kestrel Interactive Development System (KIDS) provides knowledge-based support for the derivation of correct and efficient programs from formal specifications. We trace the use of KIDS in deriving an algorithm for solving a problem arising from the design of sonar and radar signals. This derivation illustrates algorithm design, a generalized form of deductive inference, program simplification, finite differencing optimization, partial evaluation, case analysis, and data type refinement. All of the KIDS operations are automatic except the algorithm design tactics which presently require some interaction. Dozens of programs have been derived using the KIDS environment and we believe that it could be developed to the point where it can be used for routine programming.

How to decrease labor and improve reliability in the development of efficient implementations of nonnumerical algorithms and labor intensive software is an increasingly important problem as the demand for computer technology shifts from easier applications to more complex algorithmic ones; e.g., optimizing compilers for supercomputers, intricate data structures to implement efficient solutions to operations research problems, search and analysis algorithms in genetic engineering, complex software tools for workstations, design automation, etc. It is also a difficult problem that is not solved by current CASE tools and software management disciplines, which are oriented towards data processing and other applications, where the implementation and a prediction of its resource utilization follow more directly from the specification. Recently, Cai and Paige reported experiments suggesting a way to implement nonnumerical algorithms in C at a programming rate (i.e., source lines per second) t...

The analysis of set-based programs is sometimes facilitated by the computational model of a set machine; i.e., a uniform cost sequential RAM augmented with an assortment of primitives on finite sets, under the assumption that associative operations, e.g., set membership, take unit time. In this paper we give broad sufficient conditions in which to simulate a set machine on a RAM (without set primitives) in real time. Two variants of a RAM are considered. One allows for pointer and cursor access. The other permits only pointer access. Our translation method introduces a new programming methodology for data structure design and provides a new framework for investigating automatic data structure selection for set-based programs. November 10, 1994 ############### 1 Part of this work was done while the author was a summer faculty at IBM T.J. Watson Research Center. This work is also partly based on research supported by the Office of Naval Research under Contract No. N00014-87-K-0461 and b...

This paper describes the theoretical framework and an implemented system (Dtre) for the specification and verified refinement of specifications using operations on abstract data types. The system is semi-automatic in that users can specify some (possibly none) of the implementations and the system will determine the rest of the implementations. Data types are specified as parameterized theories within many-sorted first-order logic; usually these theories are centered around inductive sorts. Abstract specifications (theories) are refined in a stepwise fashion into increasingly more concrete theories. Our primary method of refinement is based on theory interpretation [1, 2, 3]. Theories and interpretations provide a clean, logically based separation between types and their implementations; thus permitting specification to proceed independently of implementation while simultaneously providing a basis for rapid and verifiably correct transformation to efficient code. Dtre provides a conven...

The structure of an existing optimizer for the very high-level, set theoretically oriented programming language SETL is described, and its capabilities are illustrated. The use of novel techniques (supported by state-of-the-art interprocedural program analysis methods) enables the optimizer to accomplish various sophisticated optimizations, the most significant of which are the automatic selection of data representations and the systematic elimination of superfluous copying operations. These techniques allow quite sophisticated data-structure choices to be made automatically. Categories and Subject Descriptors: D.3.2 [Programmiug Languages]: Language Classifications--very high-level languages; SETL; D.3.4 [Programming Languages]: Processors--compUers; opti-mization; 1.2.2 [Artificial Intelligence]: Automatic Programming--automatic analysis of algo-rithms; program modification; program transformation

Object abstraction supports the separation of what operations are provided by systems and components from how the operations are implemented, and is essential in enabling the construction of complex systems from components. Unfortunately, clear and modular implementations have poor performance when expensive query operations are repeated, while efficient implementations that incrementally maintain these query results are much more difficult to develop and to understand, because the code blows up significantly, and is no longer clear or modular. This paper describes a powerful and systematic method that first allows the “what ” of each component to be specified in a clear and modular fashion and implemented straightforwardly in an object-oriented language; then analyzes the queries and updates, across object abstraction, in the straightforward implementation; and finally derives the sophisticated and efficient “how ” of each component by incrementally maintaining the results of repeated expensive queries with respect to updates to their parameters. Our implementation and experimental results for example applications in query optimization, role-based access control, etc. demonstrate the effectiveness and benefit of the method.

Regular path queries are a way of declaratively expressing queries on graphs as regular-expression-like patterns that are matched against paths in the graph. There are two kinds of queries: existential queries, which specify properties about individual paths, and universal queries, which specify properties about all paths. They provide a simple and convenient framework for expressing program analyses as queries on graph representations of programs, for expressing verification (model-checking) problems as queries on transition systems, for querying semi-structured data, etc. Parametric regular path queries extend the patterns with variables, called parameters, which significantly increase the expressiveness by allowing additional information along single or multiple paths to be captured and related. This paper shows how a variety of program analysis and model-checking problems can be expressed easily and succinctly using parametric regular path queries. The paper describes the specification, design, analysis, and implementation of algorithms and data structures for efficiently solving existential and universal parametric regular path queries. Major contributions include the first complete algorithms and data structures for directly and efficiently solving existential and universal parametric regular path queries, detailed complexity analysis of the algorithms, detailed analytical and experimental performance comparison of variations of the algorithms and data structures, and investigation of efficiency tradeoffs between different formulations of queries. Categories and Subject Descriptors D.2.4 [Software Engineering]: Software/Program verification—model

Schwartz et al. described an optimization to implement built-in abstract types such as sets and maps with efficient data structures. Their transformation rests on the discovery of finite universal sets, called bases, to be used for avoiding data replication and for creating aggregate data structures that implement associative access by simpler cursor or pointer access. The SETL implementation used global analysis similar to classical dataflow for typings and for set inclusion and membership relationships to determine bases. However, the optimized data structures selected by this optmization did not include a primitive linked list or array, and all optimized data structures retained some degree of hashing. Hence, this heuristic approach did not guarantee a uniform improvement in performance over the use of default representations. The analysis was complicated by SETL's imperative style, weak typing, and low level control structures. The implemented optimizer was large (about 20,000 line...

We present role logic, a notation for describing properties of relational structures in shape analysis, databases, and knowledge bases. We construct role logic using the ideas of de Bruijn's notation for lambda calculus, an encoding of first-order logic in lambda calculus, and a simple rule for implicit arguments of unary and binary predicates.