Program representation size in an intermediate language with intersection and union types

The CIL compiler for core Standard ML compiles whole programs using a novel typed intermediate language (TIL) with intersection and union types and flow labels on both terms and types. The CIL term representation duplicates portions of the program where intersection types are introduced and union types are eliminated. This duplication makes it easier to represent type information and to introduce customized data representations. However, duplication incurs compile-time space costs that are potentially much greater than are incurred in TILs employing type-level abstraction or quantification. In this paper, we present empirical data on the compile-time space costs of using CIL as an intermediate language. The data shows that these costs can be made tractable by using sufficiently fine-grained flow analyses together with standard hash-consing techniques. The data also suggests that non-duplicating formulations of intersection (and union) types would not achieve significantly better space complexity.National Science Foundation (CCR-9417382, CISE/CCR ESS 9806747); Sun grant (EDUD-7826-990410-US); Faculty Fellowship of the Carroll School of Management, Boston College; U.K. Engineering and Physical Sciences Research Council (GR/L 36963, GR/L 15685

The Substance of Gloup

An essay on Gloup, the Gloucestershire group of concrete poets, including dom sylvester houedard (dsh), Ken Cox, John Furnival, concentrating in particular on the relationship between Cox and houedard and looking at the implications of this radical legacy for contemporary thought and practice. INDEX|press is a small artist run magazine and gallery programme based in Stroud with a radical international programme

項書き換えシステムの合流性自動判定法

Tohoku University外山芳

The programming language jigsaw: mixins, modularity and multiple in heritance

technical reportThis dissertation provides a framework for modularity in programming languages. In this framework known as Jigsaw, inheritance is understood to be an essential linguistic mechanism for module manipulation. In Jigsaw, the roles of classes in existing languages are "unbundled," by providing a suite of operators independently controlling such effects as combination, modification encapsulation name resolution and sharing all on the single notion of module. All module operators are forms of inheritance Thus, inheritance is not in conflict with modularity in this system but is indeed its foundation This allows a previously unobtainable spectrum of features to be combined in a cohesive manner including multiple inheritance mixins, encapsulation and strong typing. Jigsaw has a rigorous semantics based upon a denotational model of inheritance Jigsaw provides a notion of modularity independent of a particular computational paradigm Jigsaw can therefore be applied to a wide variety of languages especially special purpose languages where the effort of designing specific mechanisms for modularity is difficult to justify but which could still benefit from such mechanisms. The framework is used to derive an extension of Modula-3 that supports the new operations An efficient implementation strategy is developed for this extension The performance of this scheme is on a par with the methods employed by the highest performance object oriented language processors currently available

Strengthening Software Authentication with the ROSE Software Suite

Many recent nonproliferation and arms control software projects include a software authentication regime. These include U.S. Government-sponsored projects both in the United States and in the Russian Federation (RF). This trend toward requiring software authentication is only accelerating. Demonstrating assurance that software performs as expected without hidden ''backdoors'' is crucial to a project's success. In this context, ''authentication'' is defined as determining that a software package performs only its intended purpose and performs said purpose correctly and reliably over the planned duration of an agreement. In addition to visual inspections by knowledgeable computer scientists, automated tools are needed to highlight suspicious code constructs, both to aid visual inspection and to guide program development. While many commercial tools are available for portions of the authentication task, they are proprietary and not extensible. An open-source, extensible tool can be customized to the unique needs of each project (projects can have both common and custom rules to detect flaws and security holes). Any such extensible tool has to be based on a complete language compiler. ROSE is precisely such a compiler infrastructure developed within the Department of Energy (DOE) and targeted at the optimization of scientific applications and user-defined libraries within large-scale applications (typically applications of a million lines of code). ROSE is a robust, source-to-source analysis and optimization infrastructure currently addressing large, million-line DOE applications in C and C++ (handling the full C, C99, C++ languages and with current collaborations to support Fortran90). We propose to extend ROSE to address a number of security-specific requirements, and apply it to software authentication for nonproliferation and arms control projects

Programmiersprachen und Rechenkonzepte

Seit 1984 veranstaltet die GI-Fachgruppe "Programmiersprachen und Rechenkonzepte" regelmäßig im Frühjahr einen Workshop im Physikzentrum Bad Honnef. Das Treffen dient in erster Linie dem gegenseitigen Kennenlernen, dem Erfahrungsaustausch, der Diskussion und der Vertiefung gegenseitiger Kontakte. In diesem Forum werden Vorträge und Demonstrationen sowohl bereits abgeschlossener als auch noch laufender Arbeiten vorgestellt, unter anderem (aber nicht ausschließlich) zu Themen wie - Sprachen, Sprachparadigmen - Korrektheit von Entwurf und Implementierung - Werkzeuge - Software-/Hardware-Architekturen - Spezifikation, Entwurf - Validierung, Verifikation - Implementierung, Integration - Sicherheit (Safety und Security) - eingebettete Systeme - hardware-nahe Programmierung. In diesem Technischen Bericht sind einige der präsentierten Arbeiten zusammen gestellt

Combining Static and Dynamic Analysis for Bug Detection and Program Understanding

This work proposes new combinations of static and dynamic analysis for bug detection and program understanding. There are 3 related but largely independent directions: a) In the area of dynamic invariant inference, we improve the consistency of dynamically discovered invariants by taking into account second-order constraints that encode knowledge aboutinvariants; the second-order constraints are either supplied by the programmer or vetted by the programmer (among candidate constraints suggested automatically); b) In the area of testing dataflow (esp. map-reduce) programs, our tool, SEDGE, achieves higher testing coverage by leveraging existinginput data and generalizing them using a symbolic reasoning engine (a powerful SMT solver); c) In the area of bug detection, we identify and present the concept of residual investigation: a dynamic analysis that serves as theruntime agent of a static analysis. Residual investigation identifies with higher certainty whether an error reported by the static analysis is likely true

FOAL 2002 Proceedings: Foundations of Aspect-Oriented Langauges Workshop at AOSD 2002

Aspect-oriented programming is a new area in software engineering and programming languages that promises better support for separation of concerns. The first Foundations of Aspect-Oriented Languages (FOAL) workshop was held at the 1st International Conference on Aspect-Oriented Software Development in Enschede, The Netherlands, on April 22, 2002. This workshop was designed to be a forum for research in formal foundations of aspect-oriented programming languages. The call for papers announced the areas of interest for FOAL as including, but not limited to: formal semantics, formal specification, verification, theory of testing, aspect management, theory of aspect composition, and aspect translation and rewriting. The call for papers welcomed all theoretical and foundational studies of this topic. The goals of this FOAL workshop were to: • Explore the formal foundations of aspect-oriented programming. • Exchange ideas about semantics and formal methods for aspect-oriented programming languages. • Foster interest in the programming language theory communities concerning aspects and aspect- oriented programming languages. • Foster interest in the formal methods community concerning aspects and aspect-oriented programming. In addition, we hoped that the workshop would produce an outline of collaborative research topics and a list of areas for further exploration. The papers at the workshop, which are included in the proceedings, were selected from papers submitted by researchers worldwide. Due to time limitations at the workshop, not all of the submitted papers were selected for presentation

The Best of Both Worlds:Linear Functional Programming without Compromise

We present a linear functional calculus with both the safety guarantees expressible with linear types and the rich language of combinators and composition provided by functional programming. Unlike previous combinations of linear typing and functional programming, we compromise neither the linear side (for example, our linear values are first-class citizens of the language) nor the functional side (for example, we do not require duplicate definitions of compositions for linear and unrestricted functions). To do so, we must generalize abstraction and application to encompass both linear and unrestricted functions. We capture the typing of the generalized constructs with a novel use of qualified types. Our system maintains the metatheoretic properties of the theory of qualified types, including principal types and decidable type inference. Finally, we give a formal basis for our claims of expressiveness, by showing that evaluation respects linearity, and that our language is a conservative extension of existing functional calculi.Comment: Extended versio