Research And Realization Of Scripting Interpreter In Knitting CAD System

Knitting CAD system is a man-machine interface for Computerized Flat Knitting Machine system. The current knitting CAD system is almost developed just for one kind of machine, such as the Japanese Pattern Preparation system for SES-ONE, the German STOLL Pattern Preparation system for CMS. And these systems can not be developed by the different users in according to their own needs. In the modern time, commonality is becoming more and more important. Software lack of flexible can not meet the market demand.The main purpose of this paper is to upgrade the special knitting CAD system to a common system, make it to be the same industry as AutoCAD software. It is no longer only for one kind of machine, but widely applicable to all types of flat knitting machine. At the same time it provides open design interface for different designers, which not only to realize self-definition of the formula, but also to define different function-models. This flexible design is realized by embedding the script interpreter into CAD system, which is the bridge of user and knitting CAD system. User development can be done through the interpreter.At first, in the paper, some basic concepts of the scripting language and script interpreter are discussed, and the background, the contents and importance of this paper are pointed out. Then, the basic functions that the system should provide and design principles according to the features and requirements of the system are considered, and the overall structure of the script interpreter is designed on this basis. Next, developing tool and data structures that realizing the system should require are discussed in this paper.In the part of the paper about realization of the system. At first, two scripting languages--Delphi and C++ Script both supported by this scripting interpretation are introduced, including their grammar rules, the script structure, data types. Then the front-end script interpreter model is explained, including three modules: lexical analysis model, grammar analysis model and semantic checks model. A common object model is built by using object-oriented modeling approach, which is used to store various types of variable. And its inheritance is used to support some one variable.The establishment of grammar tree is one of the important part of the script interpreter. In this paper, a special data structure~XML document is used to store the tree. This data structure has clear hierarchy, and the father nodes and son nodes can be found easily. The method of making XML document is described in the paper. In the end, the way about how to self-define formula when the script interpreter used in the Knitting CAD system is explained.By the method of modeling and designing based on Object Modeling Technique (OMT), the main function of the script interpreter is realized in this paper, which C++ Script and Delphi Script are both supported. Man-machine interface of user and Knitting CAD System is realized by embedded method. The knitting CAD system with an open interface to users is realized, and users are allowed to make a secondary development.