Stuttgart, Univ., Fakultät Informatik, Studienarb., 1998.

The goal of this thesis is to design and implement a modern parser generator. The result is a program that reads description of some context-free LALR(1) grammar and semantic actions from an input file. To output files the program generates source codes in several target modern object-oriented programming languages for implementation of the syntax analyzer which, when parsing the language corresponding to the given grammar, executes the given semantic actions. Powered by TCPDF (www.tcpdf.org)

Objective: This document is not an introduction to parser generators. Readers should rather have a good understanding of them, especially of LALR parser generators. This document merely describes the main aspects of the implementation of a LALR parser generator named wisent. It is divided into a concise description of the programming interface and an overview over the data structures and specifics of the implementation of the wisent parser generator.

This Master’s thesis presents an algorithm that finds the semantic differences between two versions of files, an older version and a new modified version of the file. The algorithm is responsible for finding changes in the program’s behavior and displaying them graphically. By this a lot of time can be saved because it is not necessary to go through the whole file to find the differences.   The program, Semantic Diff, developed in this master thesis uses the Javacc parser generator which is used to parse files and generate the abstract syntax tree for them. Using this tree it is possible to see all the methods, classes, constructors and parameters for both older version and modified version.  By comparing all the methods, classes and interfaces of both the versions it is possible to find the differences that change the program behavior.   The algorithm for finding semantic differences has been evaluated by testing it on various test cases. By making changes in the original file and in the modified file. Like adding methods and deleting methods and adding classes to the files. The algorithm highlights those methods with green color which are added newly in the modified file and highlights the methods with red color in the original file which got deleted in modified file. This algorithm also finds the textual difference between two files and highlights those lines which are changed in modified file and which got deleted from original file.

<p>This Master’s thesis presents an algorithm that finds the semantic differences between two versions of files, an older version and a new modified version of the file. The algorithm is responsible for finding changes in the program’s behavior and displaying them graphically. By this a lot of time can be saved because it is not necessary to go through the whole file to find the differences.</p><p> </p><p>The program, Semantic Diff, developed in this master thesis uses the Javacc parser generator which is used to parse files and generate the abstract syntax tree for them. Using this tree it is possible to see all the methods, classes, constructors and parameters for both older version and modified version.  By comparing all the methods, classes and interfaces of both the versions it is possible to find the differences that change the program behavior.</p><p> </p><p>The algorithm for finding semantic differences has been evaluated by testing it on various test cases. By making changes in the original file and in the modified file. Like adding methods and deleting methods and adding classes to the files. The algorithm highlights those methods with green color which are added newly in the modified file and highlights the methods with red color in the original file which got deleted in modified file. This algorithm also finds the textual difference between two files and highlights those lines which are changed in modified file and which got deleted from original file.</p><p> </p>

Made available in DSpace on 2014-06-12T15:58:50Z (GMT). No. of bitstreams: 2 arquivo4730_1.pdf: 1803717 bytes, checksum: dc74518aee32c5757aeb57c3b0776021 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / XML (eXtensible Markup Language) tem sido um padrão bastante usado para armazenar, manipular e trocar dados. Mas para serem úteis, esses dados precisam estar disponíveis de alguma maneira para a aplicação. Existem duas APIs (Application Programming Interface) que disponibilizam dados XML para as aplicações, uma baseada em objetos e outra baseada em eventos. Essas são representadas, respectivamente, por DOM - Document Object Model e por SAX - Simple API for XML. A escolha de qual API utilizar será baseado nos requisitos das aplicações e nas características das APIs. Estas APIs são implementadas por ferramentas chamadas parsers. Cada parser possui suas próprias características. A escolha do parser é um importante critério para o desempenho das aplicações, pois grande parte do processamento ficará concentrada nele. Este trabalho tem como objetivo realizar um estudo comparativo entre as APIs DOM e SAX, mostrando as características destas APIs, suas vantagens e desvantagens, onde cada uma obtém melhor desempenho, e seu comportamento em uma aplicação. Adicionalmente é feita uma análise de algumas ferramentas de processamento de documentos XML encontradas no mercado, mostrando as características e a performance de cada uma

Objective: This document is not an introduction to parser generators. Readers should rather have a good understanding of them, especially of LALR parser generators. This document merely describes the main aspects of the implementation of a LALR parser generator named wisent. It is divided into a concise description of the programming interface and an overview over the data structures and specifics of the implementation of the wisent parser generator.

The thesis treats the problem of error correction in a context free language, and the design of an error correcting parser for the BASIC language. Two important things can be said about this thesis. First, it presents the problem of error correction in a context free language, and the existing results in the field. The concept of a context free language as a model for a programming language, and the definitions and results used later are presented or reviewed. A distance between two strings is defined and used to develop a “minimum distance error correcting parser”. Second, the thesis develops two global error correcting parsers. The first one is the top-down global error correcting parser, obtained by transforming Unger’s top-down parser into an error correcting one. Then the idea of Graham and Rhodes, of condensing the surrounding context of error, is extended, and a global simple precedence error correcting parser is obtained by analysing the whole content of the error, available from the input string. These parsers, and other known methods are then used to design and partially implement an error correcting parser for BASIC.

OMCCp is a new generation (not yet released) of the OpenModelica Compiler-Compiler parser generator which contains an LALR parser generator implemented in the MetaModelica language with parsing tables generated by the tools Flex and GNU Bison. It also contains very good error handling and is integrated with the MetaModelica semantics specification language.   The main benefit with this master thesis project is the development of new version of OMCCp with complete support for an extended Modelica grammar for a complete OMCCp-based Modelica parser. The implemented parser has been tested and the results have been analyzed. This is a new enhanced generation OMCCp with improvements made from the previous version. This version support Modelica as well as the language extensions for MetaModelica, ParModelica, and optimization problem specification. Moreover, the generated parsers are about three times faster than those from the old OMCCp.

Detta arbete har bedrivits i syfte att kartlägga funktionalitet, teknik och användningsområde gällande Web Services. Innehållet utgör således en teoretisk utvärdering av Web Services, samt tester av grundläggande programmeringslösningar. De frågor arbetet ämnar besvara är hur en Web Services på lämpligt sätt kan baseras på en befintlig tjänst, samt på vilket sätt denna Web Services kan göra aktuell tjänst lättare att använda. Dessutom belyses eventuella problem som kan uppstå i samband med denna Web Services-anpassning. I syfte att presentera ett lösningsförslag på ovan nämnda frågor granskades, via en litteraturstudie, ett antal informatikrelaterade begrepp liksom faktorer förknippade med kommersiell verksamhet på Internet. Erhållen teoretisk fakta analyserades via empiriskt arbete. Resultaten av analysen indikerar att en Web Services baserad på karttjänsten MapService kan innebära vissa fördelar för det aktuella företaget såväl som för deras kunder. Att bredda tjänsteutbudet med en marknadsdominerande standard innebär vissa fördelar för ett företag, inte minst i form av ett potentiellt större kundunderlag. Kundens vinster utgörs främst av för ändamålet utformade toolkits. Dessa hjälpmedel och verktyg underlättar implementationen av aktuell tjänst. Den ansats som här valts, att designa Web Servicen som en parser (tolk/konverterare) vars huvudsakliga syfte är att förmedla kommunikation mellan användare och befintlig tjänst, har vissa fördelar. Främst det faktum att redan befintlig funktionalitet kan utnyttjas. All kommunikation mellan användare och server hanteras av Web Servicen, som enligt denna princip utgör ett nytt gränssnitt med vilket tjänsten MapService kan användas. Till följd av det omfattande teoretiska utredningsarbetet har detta arbete inte genererat några prototyper, annat än på ett teoretiskt plan. Det problem som återstår är att utreda exakt hur ovan nämnda parser skall vara utformad, för att sedan implementera all funktionalitet som en helhet.