GDL is a language prescription which describes geometric scenes of interlinked objects. Its spirit is based on classics such as Cabri, Cinderella and Dr. Geo. But the goal is much higher: to become the engine of a full fledged free CAD system and physics modelization program.

At this stage, it generates complex 2D geometric constructions with ruler and compass, geometrical loci and animations. It works in any X11 compatible machine and renders PostScript graphics.

The snag: the interface is not quite user-friendly and is going to be re-written in full as a GUI. Nonetheless, it shall remain script oriented, and a bison parser is going to be used in order to simplify the syntaxis.

The GDL interpreter which has been implemented understands version 0.3 of the GDL-prescription (which, to be true, we are working out as we go), which may be read in this TeX file.

But the reader might be weary of so much talk and would like to take a peep at a graphical output of the program. OK, here you are:

A simple sample program, with comments, is here:

'P' [point(100,200)]	Point by coord.
'r' [ext['P'][point(200,100)]	segment from P to another coord point
's' [segm(0,150,300,150)]	segment by coord
'S' [int['r']['s']]	intersection between r and s
'C' [circle(70,70,20)]	circle by coord.
't' [ext['S'][center['C']]]	segm from S to the center of C
'C2' [compass['P']['S']]	circ centered at P and passing thru S

This project is at a very early stage and needs much help in order to develop it. Even small hints and moral support are quite welcome!