PolyGen is a program for generating random sentences according to a
grammar definition, that is following custom syntactical and lexical
rules.
It takes a text file as source program defining a grammar by means of
BNF-like rules and executes it, eventually showing the result.
Here a source program is a grammar definition, the execution consists in
the exploration of such grammar by selecting a random path and the
result is the sentence built on the way.