Sequence container

Abstract: The Object-Oriented Program Support (OOPS) class library is a portable collection of classes similar to those of Smalltalk-80 that has been developed using the C++ programming language under the UNIX operating system. The OOPS library includes generally useful data types, such as String, Date and Time, and most of the Smalltalk-80 collection classes such as OrderedCtn (indexed arrays), LinkedList (singly linked lists), Set (hash tables), and Dictionary (associative arrays). Arbitrarily complex data structures comprised of OOPS and user-defined objects can be stored on disk files or moved between UNIX processes by means of an object I/O facility. The classes Process, Scheduler, Semaphore and SharedQueue provide multiprogramming with coroutines. This paper gives a brief introduction to object-oriented programming and how it is supported by the C+ + programming language. An overview of the OOPS library is also presented, followed by a programming example. The implementation details of two of the class library's more interesting features, object I/O and processes, are described. The paper concludes with a discussion of the differences between the OOPS library and Smalltalk-80 and some observations based on our programming experience with C++ and OOPS.

Abstract: A data structure and method for dynamic type resolution in mapping abstract syntax notation (ASN.1) onto an object-oriented programming language (C++). For each information object class in ASN.1, two C++ classes are generating, a "set class" that models information object sets in that ASN.1 class, and a "class class" that models information objects in that ASN.1 class. For each information object set in an ASN.1 module class, a C++ data member is defined and a virtual resolve method is generated that may be invoked during the decoding process to permit dynamic extension of each information object set. A coder environment is provided in C++ that has pointers to instances of the various C++ module classes, enabling selective control of the type resolution information presented to the decoder.

Abstract: Templates are a powerful but poorly understood feature of the C++ language. Their syntax resembles the parameterized classes of other languages (e.g., of Java). But because C++ supports template specialization, their semantics is quite different from that of parameterized classes. Template specialization provides a Turing-complete sub-language within C++ that executes at compile-time. Programmers put this power to many uses. For example, templates are a popular tool for writing program generators. The C++ Standard defines the semantics of templates using natural language, so it is prone to misinterpretation. The meta-theoretic properties of C++ templates have not been studied, so the semantics of templates has not been systematically checked for errors. In this paper we present the first formal account of C++ templates including some of the more complex aspects, such as template partial specialization. We validate our semantics by proving type safety and verify the proof with the Isabelle proof assistant. Our formalization reveals two interesting issues in the C++ Standard: the first is a problem with member instantiation and the second concerns the generation of unnecessary template specializations.

Abstract: Most software applications use a relational database for data management and storage. Interaction with such a database is often done by letting the program construct strings with valid SQL statements, which are then sent for execution to the database engine. The fact that these statements are only checked for correctness at runtime is a source for many potential problems such as type and syntax errors and vulnerability to injection attacks.The ARARAT system presented here offers a method for dealing with these predicaments, by coercing the host C++ compiler to do the necessary checks of the generated strings. A library of templates and preprocessor directives effectively extends C++ with a little language representing an augmented relational algebra formalism. Type checking of this language extension, carried out by our template library, assures, at compile-time, the correctness and safety of the generated SQL strings. That is to say that all SQL statements constructed by the system are syntactically correct, legal with respect to the database schema, and immune to injection attacks.Standard techniques (e.g., "expression templates") for compile time representation of symbolic structures, are enhanced in our system to support a type system (featuring structural equivalence) and a symbol table lookup of the symbolic structure. Our work may also open the way for embedding other domain specific languages in C++.The system provides also initial support for the task of defining C++ data structures required for storing the results returned by database queries. An optional pre-processor can be used to define the database scheme to the C++ program.