As both computer languages and architectures continue to proliferate, there is a continuing need for new compilers. Researchers have attempted to ease the work of producing compilers by developing methods to automate compiler writing. While much work has been done (and considerable success achieved) in writing parsers which can handle a variety of source languages (using mainly table-driven analysis methods), less progress has been made in formalizing the code generation end of the compiler. Nevertheless, some of the more recent publications in code generation stress portability or retargetability of the resulting compiler. A number of code generator synthesisers have been developed, some of which produce code that can be compared in quality with that produced by a conventional code generator. However, because of the complexity of generalizing the mapping from source language to target machine, and the need for efficiency of various kinds, code generator synthesisers are large, complicated programs. Consequently, the person who develops a code generator using one of these tools invariably needs to be a code generation specialist himself. Many compilers follow a pattern of having a front end which generates intermediate code, and a back end which converts intermediate code to machine code. The intermediate code is effectively machine independent, or can be designed that way. With these points in mind, we have set out to write a system of programs which -- 1. will allow the generation of such a back end in a reasonably short time, for a general intermediate code, and for a general machine code, and -- 2. can be used by anyone who has a sound knowledge of the target machine's architecture and associated assembler language, but is not necessarily a specialist compiler writer. The system consists of a series of friendly, interactive programs by means of which the user sets up tables defining the architecture and assembly level instructions for the target machine, and the code templates onto which intermediate codes produced by a parser have been mapped. A general notation has been developed to represent machine instructions using the same format as the target assembler. Thus the code generator writer is able to write code sequences to perform the effects of the intermediate codes, using assembly mnemonics familiar to him. The resultant table-driven code generator simply replaces a sequence of intermediate codes by their respective code templates, relocating them in memory and filling in addresses known only at code-generation time. This thesis describes the use and implementation details of this generalized code generation system. As an example, the implementation of a code generator for a CLANG [23] parser on an 8080 processor is described. The discussion also includes guide-lines on how to implement a loader and associated run-time routines for use in executing the object code. The results of a number of bench-marks have shown, as expected, that code produced by a code generator developed in this manner is larger and slower than that from a special purpose optimizing code generator, but is still several times faster than interpreting the intermediate code. The major benefit to be gained from using this system lies in the shorter development time by a less skilled person. / KMBT_223 / Adobe Acrobat 9.53 Paper Capture Plug-in

Made available in DSpace on 2014-10-09T12:55:19Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:56Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:55:19Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:56Z (GMT). No. of bitstreams: 0 / O Laboratório de Análise por Ativação com Nêutrons (LAN) do Instituto de Pesquisas Energéticas e Nucleares (IPEN), utiliza esta técnica analítica multielementar, baseada na irradiação de uma amostra por um feixe de nêutrons oriundos de um reator nuclear, que induz a radioatividade; que é medida em um espectrômetro de raios gama, para a obtenção dos espectros de raios gama. Neste trabalho é implementado um software denominado de SAANI (Software Análise por Ativação com Nêutrons Instrumental) para análise de espectros de raios gama, desenvolvido para os usuários do laboratório LAN-IPEN, com a filosofia de software livre, para a substituição do software existente VISPECT/VERSÃO 2, e tem como características principais: tornar a interface mais amigável; facilitar a padronização dos procedimentos realizados pelos pesquisadores, estudantes e técnicos; ser extensível com a utilização da tecnologia de plugins; multiplataforma; código livre. O software foi desenvolvido utilizando a linguagem de programação Python, a biblioteca gráfica Trolltech Qt e algumas de suas extensões científicas. Os resultados preliminares obtidos utilizando o software SAANI foram comparados aos obtidos com o software existente e foram considerados bons. Algumas diferenças encontradas foram verificadas oriundas de erros de precisão na implementação do software. O software SAANI está instalado nos computadores de usuários selecionados para a execução de rotinas de análise para uma maior verificação de sua robustez, precisão e usabilidade. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

IV is a very high level language designed for use in a real time production control environment. While most fourth generation languages are intended for use by end users, IV is more suitable for skilled professional programmers. One of the major design objectives of IV is a dramatic improvement in programmer efficiency during application program development. Non-procedural constructs provided by the language and the use of a number of interactive development tools provide an environment for achieving this goal. This report presents a language proposal for IV, and addresses related design and implementation issues.

CSP (Communicating Sequential Processes) is a notation proposed by Hoare, for expressing process communication and synchronization. Although this notation has been widely acclaimed, Hoare himself never implemented it as a computer language. He did however produce the necessary correctness proofs and subsequently the notation has been adopted (in various guises) by the designers of other concurrent languages such as Ada and occam. Only two attempts have been made at a direct and precise implementation of CSP. With closer scrutiny, even these implementations are found to deviate from the specifications expounded by Hoare, and in so doing restrict the original proposal. This thesis comprises two main sections. The first of these includes a brief look at the primitives of concurrent programming, followed by a comparative study of the existing adaptations of CSP and other message passing languages. The latter section is devoted to a description of the author's attempt at an original implementation of the notation. The result of this attempt is the creation of the CSP-i language and a suitable environment for executing CSP-i programs on an IBM PC. The CSP-i implementation is comparable with other concurrent systems presently available. In some aspects, the primitives featured in CSP-i provide the user with a more efficient and concise notation for expressing concurrent algorithms than several other message-based languages, notably occam. / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in

The design and implementation of the interactive graphics language IGL is described. This language not only allows the definition and display of line drawings but also has full facilities for manipulating, naming, identifying and interacting with such drawings. The language has been implemented as an extension to Fortran IV using the XPL compiler generator system. The experience gained so far in the use of the language has already proven a number of advantages over present-day graphics systems. The language is readily learned by users with previous high-level language experience. As no extensive testing and documentation is necessary due to the readability of the program, the time required for the completion of a project is greatly reduced. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

We begin with a disucssion of some of the serious deficiencies of first order predicate languages. These include the non-characterizability by first order sentences of such common mathematical structures as the class of well-ordered sets, the class of finite sets, the class of Archimedean fields and the standard models of arithmetic and analysis. Two methods of generalizing first order predicate languages are then studied. The first approach is to allow for "expressions of infinite length"; the second method is the introduction of "generalized quantifiers." For the languages resulting from each approach, we consider to what extent such deficiencies as those mentioned above may be overcome and also to what extent some of the elementary model-theoretic and proof-theoretic theorems of first order logic may be generalized to these new languages. Among the languages with expressions of infinite length, we first consider the Lω₁ω languages which generalize first order languages by extending the recursive definition of a formula to allow countable conjunctions and disjunctions of formulas as formulas. It is shown that with the use of such languages we are able to describe categorically the standard model of arithmetic, the class of finite sets, the class of Archimedean fields and other common mathematical structures which cannot be characterized in first order languages. Generalizations of the Lowenheim-Skolem and completeness theorems of first order logic are given as well as a countable isomorphism theorem due to Dana Scott. We make use of a characterization of rank equivalence due to Carol Karp to demonstrate that neither the standard model of analysis nor the class of well-ordered sets may be described in any Lω₁ω -language. In fact, our argument indicates that these characterizations are not possible in any extension of a Lω₁ω - language which, for any infinite cardinal α , allows as formulas conjunctions and disjunctions of less than a formulas. This result leads us naturally to a consideration of the class of Lω₁ω - languages, any element of which is obtained from a Lω₁ω - language by modifying the rules for formula formation to allow not only denumerable conjunctions and disjunctions but also quantifications over denumerable sets of variables. (These ideas are made more precise in the text of the thesis.) The standard model of analysis and the class of well-ordered sets are each seen to be characterizable by single Lω₁ω - sentences. Other infinitary languages are also mentioned, including languages with infinitely long atomic formulas. Among the languages with generalized quantifiers we restrict ourselves to the L(Qα) - languages, where α is an ordinal, which are obtained from first order languages by adding a new quantifier symbol Qα to be read "there exist Ɲα... .” In addition to being able to characterize sets of various cardinalities, we give a categorical description of the standard model of arithmetic by a single L(Qօ) - sentence. Among the model-theoretic results possible are generalizations of the compactness theorem, Lŏs's theorem and the downward Lowenheim - Skolem theorem of first order logic. Finally, on the proof-theoretic side, we show that in the case α = 0 there exists no recursive axiomatization which yields a completeness result; in the case α = 1 , however, such an axiomatization is possible. / Science, Faculty of / Mathematics, Department of / Graduate

With the increased use of computerized databases, the ability to allow users to access information using natural language is becoming more desirable. There are many natural language systems in existence today. The main problem with these systems is the amount of expertise and effort required to adapt them to a new domain. The design of a portable natural language front-end to a relational database is described in this thesis. It is designed so that a typical Database Administrator can implement a new domain in a reasonable amount of time. Database portability has been achieved by separating the domain dependent natural language definitions from the domain independent definitions. These domain dependent definitions are specified in the database schema, which is structured to extract the semantics contained in the structure of the actual database. A rich supply of standard definitions are available to both aid in the development of the database schema and to help force consistency amongst database domains. / Science, Faculty of / Computer Science, Department of / Graduate

This thesis describes research which was carried out to determine whether novices could program in fourth generation languages as well as experienced third generation programmers. It was thought that experience with a third generation language could be transferred to a fourth generation environment. This hypothesis was tested using a completely randomized block design lab experiment consisting of two factors and a block. The two factors were experience with third generation languages, and complexity of the task. The block was the educational institution where the lab sessions were conducted. Each of the factors and the block had two levels. The specific hypotheses tested were: 1. Experienced third generation language programmers will record higher mean scores on both simple and complex tests of fourth generation languages. 2. The difference in test scores, between simple and complex fourth generation language tasks, will be greater for novices than for experienced third generation language programmers. 3. Experience with other software tools, especially report writers, query languages, and other fourth generation languages will affect the subjects' performance on the fourth generation language tests. Using FOCUS as the fourth generation language, lab sessions were run for fifty-seven subjects. The results indicate that experience with third generation languages affects a subject's performance on simple tests of fourth generation languages. The results also indicate that the experience has no effect on complex tests of fourth generation languages. Because of a lack of data, no meaningful conclusions could be reached for hypothesis number three. We feel experienced third generation language programmers scored higher than novices on simple 4GL reporting tests because experienced 3GL programmers had skills which were very similar to the skills needed in a simple 4GL reporting application. There are several possible ways of explaining why experienced programmers could do no better than novices on complex 4GL reporting tests. One possible explanation follows; because complex 4GL reporting commands are so different from third generation language commands, third generation language programmers had no advantage over novices. A second explanation might be that the complex test was too difficult, or too long. As a result of this difficulty, no one was able to perform very well. We conclude that experienced programmers should be preferred over novices when applications involve simple 4GL commands. More research is necessary to determine if in fact novices can perform as well as experienced third generation language programmers on complex 4GL tasks. / Business, Sauder School of / Graduate

A new data base independent query language for relational systems is presented. Queries in this language specify only properties of the data which is to be retrieved. An algorithm for reducing queries to a response relation is described. This reduction algorithm makes use of Micro-Planner to decide which relations in the data base are applicable to the query, and how these relations should be manipulated. A semantic model is used as the basis for this work. This query language is also compared with existing languages. / Science, Faculty of / Computer Science, Department of / Graduate