Showing papers on "Functional logic programming published in 1975"
TL;DR: Concurrent Pascal as discussed by the authors is a programming language for structured programming of computer operating systems that extends the sequential programming language Pascal with concurrent programming tools called processes and monitors, which can be expressed informally by means of pictures illustrating a hierarchical design of a simple spooling system.
Abstract: Describes a new programming language for structured programming of computer operating systems. It extends the sequential programming language Pascal with concurrent programming tools called processes and monitors. Section I explains these concepts informally by means of pictures illustrating a hierarchical design of a simple spooling system. Section II uses the same example to introduce the language notation. The main contribution of Concurrent Pascal is to extend the monitor concept with an explicit hierarchy of access rights to shared data structures that can be stated in the program text and checked by a compiler.
576 citations
TL;DR: The deduction system herein is shown to be consistent and also deduction complete with respect to Hoare's system and a subgoaler for the deduction system is described whose input is a significant subset of Pascal programs plus inductive assertions.
Abstract: Defining the semantics of programming languages by axioms and rules of inference yields a deduction system within which proofs may be given that programs satisfy specifications. The deduction system herein is shown to be consistent and also deduction complete with respect to Hoare's system. A subgoaler for the deduction system is described whose input is a significant subset of Pascal programs plus inductive assertions. The output is a set of verification conditions or lemmas to be proved. Several non-trivial arithmetic and sorting programs have been shown to satisfy specifications by using an interactive theorem prover to automatically generate proofs of the verification conditions. Additional components for a more powerful verification system are under construction.
157 citations
TL;DR: The Planner Project is constructing a programming apprentice to assist in knowledge based programming designed for interactive use by expert programmers in the meta-evaluation of implementations in the context of their contracts and background knowledge.
Abstract: The Planner Project is constructing a programming apprentice to assist in knowledge based programming. The programming apprentice is designed for interactive use by expert programmers in the meta-evaluation of implementations in the context of their contracts and background knowledge. Meta-evaluation produces a justification which makes explicit exactly how the module depends on the contracts of other modules and on the background knowledge. The justification is used in answering questions on the behavioral dependencies between modules and in analyzing the implications of perturbations in specifications and/or implementation.
80 citations
TL;DR: The programming language PASCAL is assessed in the light of “reliable programming” and with the background of five years of experience with the language, and some features are selected to point out remaining problems.
Abstract: The programming language PASCAL is assessed in the light of “reliable programming” and with the background of five years of experience with the language. Some features are selected to point out remaining problems, either inherent or specific, from which some guidelines for the design or choice of languages for reliable programming are derived. Among the discussed features are the concept of data type, the sequential file structure, and the type union.
56 citations
19 May 1975
TL;DR: What is extensibility?
Abstract: What is extensibility? What is it good for, if anything? Is it worth bothering about when designing a programming language?
51 citations
01 Jan 1975
TL;DR: The programming language Pascal is assessed in the light of `reliable programming' and with the background of five years of experience with the language, and some features are selected to point out remaining problems.
Abstract: The programming language PASCAL is assessed in the light of “reliable programming” and with the background of five years of experience with the language. Some features are selected to point out remaining problems, either inherent or specific, from which some guidelines for the design or choice of languages for reliable programming are derived. Among the discussed features are the concept of data type, the sequential file structure, and the type union.
30 citations
TL;DR: Some social aspects of pro gramming are illuminated through analogies with similar aspects of mathematics and natural languages, and it is suggested that Fortran and Cobol will remain dominant for a long time to come.
Abstract: Some social aspects of pro gramming are illuminated through analogies with similar aspects of mathematics and natural languages. The split between pure and applied mathematics is found similarly in programming. The development of natural languages toward flexionless, word-order based language types speaks for programming language design based on general, abstract constructs. By analogy with incidents of the history of artificial, auxiliary languages it is suggested that Fortran and Cobol will remain dominant for a long time to come. The most promising avenues for further work of wide influence are seen to be high quality program literature (i.e. programs) of general utility and studies of questions related to program style.
29 citations
Proceedings Article•
03 Sep 1975TL;DR: The use of a 3 valued logic, generator functions to deduce answers to model queries, the saving and maintaining of derived results, and new facilities for modeling changes produced by the occurrence of events are discussed.
Abstract: This paper presents some programming facilities for modeling the semantics of a task domain and for describing the situations that occur in that domain as a task is being carried out Each such description models a "state" of the task environment, and any given state can be transformed into a new state by the occurrence of an event that aIters the environment Such modeling systems are vital in many Al systems, particularly those that do question answering and those that do automatic generation and execution monitoring of plans The modeling mechanisms described are basically extensions and modifications of facilities typically found in Al programming languages such as PLANNER, CONN1VER, and QA4 In particular, we discuss our use of a 3 valued logic, generator functions to deduce answers to model queries, the saving and maintaining of derived results, and new facilities for modeling stntc changes produced by the occurrence of events
29 citations
IBM1
TL;DR: How structured programming methodology has been introduced into a large production programming organization using an integrated but flexible approach is discussed and recommendations based on this generally successful experience are made.
Abstract: This paper discusses how structured programming methodology has been introduced into a large production programming organization using an integrated but flexible approach. It next analyzes the advantages and disadvantages of each component of the methodology and presents some quantitative results on its use. It concludes with recommendations based on this generally successful experience, which could be useful to other organizations interested in improving reliability and productivity.
27 citations
21 citations
01 Jan 1975
TL;DR: By analogy with incidents of the history of artificial, auxiliary languages it is suggested that Fortran and Cobol will remain dominant for a long time to come in programming.
Abstract: Some social aspects of programming are illuminated through analogies with similar aspects of mathematics and natural languages. The split between pure and applied mathematics is found similarly in programming. The development of natural languages toward flexionless, word-order based language types speaks for programming language design based on general, abstract constructs. By analogy with incidents of the history of artificial, auxiliary languages it is suggested that Fortran and Cobol will remain dominant for a long time to come. The most promising avenues for further work of wide influence is seen to be high quality program literature (i.e. programs) of general utility and studies of questions related to program style.
19 May 1975
TL;DR: The past few years have witnessed an increased understanding of the relationship between programming languages and problem solving, and it has been observed that certain languages and language features are particularly well suited for the use of systematic programming techniques, while others hinder or discourage such discipline.
Abstract: The past few years have witnessed an increased understanding of the relationship between programming languages and problem solving. Programming is now understood to be a rather difficult task which requires the simultaneous application of principles, skills, and art. Computer scientists have recognized that the features of a programming language can have a significant effect upon the ease with which reliable programs can be developed. It has also been observed that certain languages and language features are particularly well suited for the use of systematic programming techniques, while others hinder or discourage such discipline. Of course, it is possible to write well-structured, clearly organized programs in any programming language, but such programs have often been the exception rather than the rule.
TL;DR: This paper proposes that the steps be expressed as proofs of a program for the eight queens problem, and the proof method is applied across two of the steps of the development.
Abstract: Wirth (1971) has proposed a method of `stepwise refinement' for writing computer programs. This paper proposes that the steps be expressed as proofs. A program for the eight queens problem is developed, and the proof method is applied across two of the steps of the development. The strengths and weaknesses of the method, and its implications for the programming process and programming language design are discussed.
TL;DR: A simple correspondence is presented between the elementary constructs of programming languages and the lambda-calculus, using intuitive, functional interpretations of programming language constructs, completely avoiding the notions of machine memory and address.
01 Apr 1975
TL;DR: The main topic of the paper is to introduce a concept for structured display programming in interactive computer graphics and to discuss the suitability of FORTRAN, ALGOL, PL/I, and APL as the host language for such a programming system.
Abstract: The main topic of the paper is to introduce a concept for structured display programming in interactive computer graphics and to discuss the suitability of FORTRAN, ALGOL, PL/I, and APL as the host language for such a programming system. To this end, the interrelationship between picture structures, data structures, and language structures is first established. Based on the obtained conclusions, a model language for interactive display programming (GRIP) is introduced. The suitability of the above mentioned languages is discussed, and experiences with the implementation of the GRIP philosophy in some of these languages are communicated.
01 Jan 1975
TL;DR: The outline of an introductory FORTRAN programming course based on structured programming is presented, using the language IFTRAN as a FORTRan preprocessor to teach program development by means of top-down stepwise refinement.
Abstract: The outline of an introductory FORTRAN programming course based on structured programming is presented. The language IFTRAN was used as a FORTRAN preprocessor, allowing regular FORTRAN statements plus more powerful conditional and looping statements. Program development was taught in the course by means of top-down stepwise refinement. Students were well motivated and developed a professional attitude towards programming.
TL;DR: This paper proposes to focus on systems that "do more" than such systems in the sense that they require less complete information about the programs they are to generate.
Abstract: An automatic programming system is a system (usually a programmed computer) that generates a program from partial information about that program (Figure 1). Looked at in this general way, automatic programming systems are hardly new. Assemblers are automatic programming systems. So are compilers, debugging systems, and even loaders. In this paper, I propose to focus on systems that "do more" than such systems in the sense that they require less complete information about the programs they are to generate.
IBM1
Proceedings Article•
03 Sep 1975TL;DR: An Interpreter for the programming language predicate logic is described and some topics are; syntax and proof procedure, procedure evocation, function transformation, goal variation and interactive computational control.
Abstract: We describe an Interpreter for the programming language predicate logic. Some topics are; syntax and proof procedure, procedure evocation, function transformation, goal variation and interactive computational control.
TL;DR: This work shows how the concept of abstract data type as realize d in CLU-can simplify the construction of provably correct programs.
Abstract: Concepts of good program structure can and should be reflected in th e design of programming languages. Thus we have two criteria for use by language designers : First, work in the area of formal proof of program correctnes s has shown that program proofs are greatly simplified if certain features are absent from the language in which the programs are expressed-for example, n o goto's, or the absence of side effects in the execution of procedures. Second : the closeness of the language to the problem domain affects the ease with whic h the programmer may express a problem solution-in particular, the data type s of the language should provide a convenient match to the abstractions of th e problem. A programming language should provide tools for building abstraction s that are natural for the problem at hand. These two design criteria are being applied to the concept of data type i n the design of the programming language CLU being developed by Professor Lisko v and colleagues at MIT[1]. I would like to show how the concept of abstract data type as realize d in CLU-can simplify the construction of provably correct programs. To thi s end we will consider the development of a program by \"stepwise refinement \" i n PASCAL and in CLU. The problem to be solved is the sequence problem studied by Niklaus Wirth[2] : On the set containing the integers 1, 2 and 3, construct a sequence o f length N containing no adjacent equal subsequences. The strategy of solution is to generate a series of candidate sequences such that :-Every sequence that could be a Good sequence is generated. It is easy to check that a candidate is a Good sequence. We start with an initial candidate-the empty sequence and form new candidates (Figure 1) by means of two operations : Extend and Change. .
TL;DR: The process of designing and evolving a programming system cannot be characterized as either top-down or bottom-up or any other well-structured process, and any combination of the two is compatible with a structured programming philosophy.
Abstract: The process of designing and evolving a programming system cannot be characterized as either top-down or bottom-up or any other well-structured process. The results, however, is a well-structured program. Since both approaches have the same goal either approach or a combination of the two is compatible with a structured programming philosophy.
TL;DR: This note describes a method of enabling non‐deterministic algorithms to be written in conventional deterministic programming languages through a dynamic manipulation of stack contents, and is contrasted with standard techniques of implementing non‐Deterministic Programming languages.
Abstract: This note describes a method of enabling non-deterministic algorithms to be written in conventional deterministic programming languages. The method involves a dynamic manipulation of stack contents, and is contrasted with standard techniques of implementing non-deterministic programming languages.
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01 Jan 1975
TL;DR: The implementation of a large compiler system is described, and conclusions are drawn about organization, time scales and the quality achieved.
Abstract: The implementation of a large compiler system is described, and conclusions are drawn about organization, time scales and the quality achieved.