src/ZF/Tools/datatype_package.ML
1999-01-12 ago eliminated global/local names;
1999-01-12 ago eliminated tthm type and Attribute structure;
1999-01-07 ago ZF: the natural numbers as a datatype
1999-01-06 ago induct_tac and exhaust_tac
1998-12-28 ago revised datatype definition package