See also the git repository.

 * 0.03 - fixed various bugs in Subpattern ->walk. Subpatterns now close
   over what they point to at time of object creation instead of at walk
   or ->render time.
 * 0.02 - Subpattern calls ->render on objects; this allows subpatterns
   to be not just simple strings. croak/confess instead of die
   especially if deep in some ->render or ->walk tree. Add ->walk so
   the parse tree can be walked through with (and possibly modified by)
   a callback.
 * 0.01 - released on a mostly unsuspecting world.