GiNaC/ginac basic.h ex.cpp ex.h registrar.h structure.h

[Christian Bauer]

Update of /home/cvs/GiNaC/ginac

Modified Files:
      Tag: ginac_1-2
	basic.h ex.cpp ex.h registrar.h structure.h 
Log Message:
- added support for (acyclic) visitors and two tree traversal algorithms
  (pre- and postorder); they even work correctly with inheritance, but
  they're dog slow: a hand-crafted tree traversal with a type switch is
  about two times faster, at least if the number of visited classes is
  small; but implementing this doesn't hurt, and maybe somebody likes to
  use visitors...
- rearranged the member functions of ex and basic in a slightly more logical
  way