An implementation of the Pattern interface for Awk regular expressions.
This class is compatible with the AwkCompiler and AwkMatcher
classes. When an AwkCompiler instance compiles a regular expression
pattern, it produces an AwkPattern instance containing internal
data structures used by AwkMatcher to perform pattern matches.
This class cannot be subclassed and cannot be directly instantiated
by the programmer as it would not make sense. It is however serializable
so that pre-compiled patterns may be saved to disk and re-read at a later
time. AwkPattern instances should only be created through calls to an
AwkCompiler instance's compile() methods