Showing papers on "Specification language published in 1972"

Preliminary report on a system for general space planning

Abstract: A computer language and a set of programs within that language are described which allow the formulating and solving of a class of space planning problems. The language is an extension of Algol and includes means to represent spaces and objects, to manipulate them, and to test the resulting arrangements according to a variety of constraints. The algorithms used to solve problems expressed in this language rely on heuristic programming. Both the language and the search algorithms are detailed.

The “most recent” error: Its causes and correction

Abstract: The notion of a general block structured programming language and the “most recent” evaluation strategy for such a language are formalized and their relationship investigated. Sufficient conditions for “most recent” correctness are obtained.

Levels of language for portable software

Abstract: An increasing amount of software is being implemented in a portable form. A popular way of accomplishing this is to encode the software in a specially designed machine-independent language and then to map this language, often using a macro processor, into the assembly language of each desired object machine. The design of the machine-independent language is the key factor in this operation. This paper discusses the relative merits of pitching this language at a high level or a low level, and presents some comparative results.

On the design and specification of a common base language

Abstract: This is the report on the work of the Computational Structures Group of Project MAC toward the design and specification of a common base language for programs and information structures We envision that the meanings of programs expressed in practical source languages will be defined by rules of translation into the base language The meanings of programs in the base language is fixed by rules of interpretation which constitute a transition system called the interpreter for the base language We view the base language interpreter as the functional specification of a computer system in which emphasis is placed on programming generality - the ability of users to build complex programs by combining independently written program modules Our concept of a common base language is similar to the abstract programs of the Vienna definition method - but a single class of abstract programs applies to all source languages to be encompassed The semantic constructs of the base language must be just those fundamental constructs necessary for the effective realization of the desired range of source languages Thus we seek simplicity in the design of the interpreter at the expense of increased complexity of the translator from a source language to the base language As an illustration of this philosophy, we present a rudimentary form of the base language in which nonlocal references are not permitted, and show how programs expressed in a simple block structured language may be translated into this base language The importance of representing concurrency within and among computations executed by the interpreter is discussed, and our approach toward incorporating concurrency of action in the base language is outlined

Derived semantics for some programming language constructs

Abstract: The constructs of a simple programming language are introduced and described informally in terms of values and side-effects. A translator is defined which translates the language into flowcharts for a simple machine. The action of the machine in executing a flowchart is defined. A proof is constructed that the effect of translating and executing any program can be expressed solely in terms of the value and side-effect of the program. During the course of constructing the proof, formal definitions of the concepts of value and side-effect are derived in order to make the proof rigorous. Correctness of the implementation involves checking that the definitions derived in the step above are an acceptable formalization of the informal description given in the first step.

A Two-Stage BNF Specification of Natural Language

Abstract: This paper presents a method of using BNF to specify natural language in such a way that a relatively small grammar of English can express the major grammatical constraints of the language and can be refined without undue proliferation of the rules. The results show that the departures of natural language from a context-free language are of a very restricted kind. The analysis obtained for sentences of the scientific literature is relevant for information processing

The structure of language : a new approach

Abstract: A power braking apparatus having a housing with a cavity therein through which a fluid under pressure is continually flowing. A piston separates the cavity into an inlet chamber and an outlet chamber. The piston has a passageway for connecting the inlet chamber from the outlet chamber. A valve in the passageway is adapted to regulate the flow of fluid from the inlet chamber to the outlet chamber. A disc located in the stem of the valve is resiliently biased against a head on the stem. One side of the disc is connected to the inlet chamber and the other is connected to the outlet chamber. An actuation input moves the valve toward a seat to restrict the flow of fluid between the inlet chamber and the outlet chamber and establish a pressure differential therebetween. This pressure differential will move the piston to provide an output force. When the pressure differential reaches a predetermined value, the resiliently biased disc on the stem will move away from the head to prevent the complete interruption of flow between the inlet chamber and the outlet chamber.

Systems for systems implementors: some experiences from Bliss

Abstract: The programming language Bliss was developed at Carnegie-Mellon University expressly for the purpose of writing software systems and has been in use for over three years. A considerable number of systems have been written using it: compilers, interpreters, i/o systems, simulators, operating systems, etc. The language was designed and implemented in the conventional sense of an isolated language system, and relies on the file system, editors, debuggers, etc., provided by the manufacturer and/or other users. In this paper we shall not describe Bliss, that has been done elsewhere; nor shall we attempt to justify the language design, that has also been done. Rather, we shall attempt to analyze and evaluate the particular decision to implement Bliss as an isolated language rather than as a piece of a more comprehensive system. Some comments are made on the implications of this analysis/evaluation on the shape that such a system might have.

The terminal control language for the madcap programming language

Abstract: This paper describes the hardware and software associated with a keyboard based, storage scope terminal interactive facility currently under development at Los Alamos. The terminal commands are given by single character operators. Editing on a line or character basis and interaction with an executing program is included. The overall approach has been one of command language and source language unification.

Some implementation issues relating to data structures for interactive graphics

Abstract: This is a tutorial paper describing the relationship between the data structure and the rest of an interactive graphics system. The distinction between data structures and storage structures is emphasized, as is the problem of data structure segmentation. The implementation of typical graphical applications is described, along with analysis of various tradeoff decisions. Finally, some high-level data structure specification languages are discussed.

A Note on Model Specification

Abstract: Regression analysis is by far the most popular of all the statistical techniques employed in financial research. Almost without exception, the models employed have been additive in both the parameters and the variables (regressors).

Telecommunication-oriented programming language for switching systems

Abstract: The paper discusses the design requirements for a real-time programming language which may be used as a high-level language in the computer control of telecommunication switching systems. Details are given of one specific telecommunication-oriented programming language (TPL1) which has been implemented as an example of the type of language thought desirable. The main requirement of this language is that it should provide a means whereby an easily readable program may be produced, and which leads to the generation of an efficient code in both storage and central-processor utilisation.

A Systems Programming Language

Abstract: In the fall of 1969 Carnegie-Mellon University acquired a PDP-10 to support the research of the Computer Science Department. This research involves the production of a substantial number of large systems programs of the type which have typically been written in assembly language, e.g., compilers, interpreters, etc. In many cases it was resolved to use a higher-level language to implement these systems. This decision immediately lead to another question: which language. In turn this lead to a consideration of the characteristics, if any, which are unique to, or at least exaggerated in, the production and maintenance of systems programs. One product of these deliberations was a new language which we call Bliss. In this paper we shall deal with the design considerations which most influenced the nature of Bliss and how these considerations manifest themselves in the language.

A programming language for the teaching of algorithmic analysis

Abstract: This report deals with the design, implementation and evolution of programming language designed specially for the teaching of Algorithmic Processes. In the first section two alternative approaches to the teaching of this first course in Computer Science are described. Next the authors state their basic hypothesis: that a programming language may be custom-designed for a given flow chart language with ensuing benefit. A flow chart language is chosen and described in detail with several examples of complete problems solved in flow chart form, Next the programming language is described and the problems solved in the previous section with flow charts are now coded in this programming language. Several simplifying features of the programming language are described. This programming language is now being utilized in a college classroom situation in order to evaluate its effectiveness as a teaching tool. A brief description of its current use and the means of its evaluation are presented in the last section.