Study And Implementation Of Key Mechanisms During Syntax Parsing In Multi-domain Modeling And Simulation Platform

Complex physical system generally is a synthesis of subsystems from different domains such as mechanical, electrical, hydraulic and control systems, should be modeled and simulated in a general program circumstance to obtain integral results of performance test and analysis. Modelica is a new language for physical modeling of multi-domain systems, which unifies and generalizes many modeling languages and supports object-oriented modeling, multi-domain modeling, declarative physical modeling and continuous/discrete-event hybrid modeling. Hence it suits the description for modern complex multi-domain systems well, and represents the new trend of modern modeling and simulation technology.This parper is based on the development of platform MWorks, which is a multi-domain physical modeling and simulation system. It studis the character of Modelica language's syntax, introduces the design process of MWorks'compiler, analyses the structure of compiler, and focus on the study of two key mechanisms which are element lookup and component modification.Lookup mechanism is one of the key contents of semantic analysis. Based on study of such technique as lookup's scope, routine and rule, this paper designs a matching lookup mechanism which takes standard lookup and lookup from top process as main process and takes such process as nested element lookup and lookup in same layer process as supported mechanism. For such problems as circular inheritance and names conflict, this parer also designs relevant schemes to handle.Modification mechanism is another key content of semantic analysis. Compared with object-oriented language's inheritance mechanism, this paper analyses the characters of component modification mechanism, introduce the usage of component modification and its rules. It chooses the scheme based on modification table after comparing with the scheme based on variable table. Suitable data and structure have been designed to support the scheme and carry it out through processes of modification parsing and instantiation. Based on the study, element lookup and component modification mechanism have been carried out in the module of MWorks/Compiler. At the end of this paper, it give a general introduction to MWorks system, and provides some practical models to run in MWorks, which testifies the key mechanisms designed in this paper.