Added InTree constraint on Pntr. InTree is implemented as a type class, similar to the technique in Hamana's paper and used here too:
Added InTree constraint on Pntr. InTree is
implemented as a type class, similar to the technique
in Hamana's paper and used here too:

http://svn.berlios.de/svnroot/repos/al4nin/trunk/purgatory/PoorKinds.lhs

cartazio/omega,minad/omega