The Language for Describing Plane Shapes (TEADI)

Abstract

This language is used to introduce into the com-pater the description of plane bodies whole contours are described with straight lines and circles. The user operates as at a drafting board with the difference that, instead of taking a ruler or a compass to draw a line or a circle, he indicates in a menu on the screen the corresponding symbols. This activates the appropriate part of the program, which asks to indicate with the light pen or to type throuth the keyboard the elements or the informations needed to complete the definition. For instance, having defined the two circles of Fig. 3, if one wants to draw the common tangents, he must indicate with the light pen the line in the menu and the two circles in the central area of the screen. Fig. 4-9 illustrate some of the possibilities of the language to help the definition of figures composed of repetitive parts. The possibility to record in a date bank the data structure of any figure to be added to that in course of definition gives a very pleasant flexibility and power to the language which is very appreciated in the case of complex figures with repetitive parts.