The Geometer's Sketchpad is a dynamic geometry software package, available for Mac and Windows computers, from Key Curriculum Press. See the JavaSketchpad Demo Gallery (part of the Java Sketchpad Center) to find out what dynamic geometry software can do.
There is a program which converts Geometer's sketches to HTML pages using the JavaSketchpad applet -- the Sketchpad HTML Converter (available from the Java Sketchpad Center). It is however also possible to write the code that describes your construction to JavaSketchpad by hand, using a normal text (or possibly HTML) editor. There can be several reasons for doing this. You might not have Geometer's sketchpad at all and still want to do dynamic geometry. You might want to create sketches by "programming" in the simple, plain text language of JavaSketchpad and not by clicking around. Or you might experience the lack of a "save" function in the demo version of Geometer's Sketchpad (which you need for using the Sketchpad HTML Converter).
My jsp.awk script simplifies the process of hand-writing JavaSketchpad code by adding a bit of convenience to the construction language. With jsp.awk you are no longer restricted to absolute numbers when referring to objects. Names and relative numbers are introduced to the language to facilitate "expressive" code and relieve you from counting through your script to find those object references. Macros can be used to define names for new constructions that you want to add to JavaSketchpads vocabulary. If the term "macro" irritates you, think of them as very similar to Geometer's Sketchpad's scripts. You can also play with a pseudo-object named "Reference" that is internally used to provide referential parameters to macros and has other applications as well.
* Note: I'm linking to a copy of the grammar modified by me and stored on this Web server. I have corrected a few errors and added some comments. You can find out about the changes here.
As you're becoming familiar with JSPs constructions and formats, you might want to have a look at this: My JSP Quick Reference page.
The transition from "old" JavaSketchpad to the construction language of jsp.awk is simple. An existing JSP construction can actually be used in jsp.awk without changes. (You only have to double every $ sign because that is the "trademark" character we use to mark jsp.awk's features.) If you write your own constructions, you will from the start find it natural to use names and relative numbers instead of absolute numbers. You don't have to, but will quickly want to use the more advanced features, especially if you are familiar with some very basic concepts of programming. For a detailed tutorial, read "using jsp.awk".
Read the Download and Install page for more information.
18. November 1997, Sebastian Lisken