7.2 Creating Grammar-Based Mimicry

Producing software to do context-free mimicry is not complicated. You only need to have a basic understanding of how to parse text, generate some random numbers, and break up data into bit levels. Appendix A shows the Java code for a complete context-free grammar system that both encodes and decodes information.

A C version of the code is also available on the code disk. It is pretty much a straight conversion.

There are a number of different details of the code that bear explaining. The best place to begin is the format for the grammar files. Figure 7.2 shows a scrap from the baseball context-free grammar that is described in full in Appendix B.

*WhapperOutfieldOut = He pops one up into deep left field./.1/      He lifts it back toward the wall where it is caught        by *BlogsOutfielder *period/.1/      He knocks it into the glove of        *BlogsOutfielder *period /.1/      He gets a real piece of it and        drives it toward the wall        where it is almost ... Oh My God! ... saved by        *BlogsOutfielder *period /.1/      He pops it up to *BlogsOutfielder *period / .2//*WeatherComment = Hmm . Do you think it...