2007-07-08 ago replaced exception TableFun/GraphFun.DUPS by TableFun/GraphFun.DUP;
2007-07-05 ago sort_le: tuned eq case;
2007-04-03 ago renamed of_sort_derivation record fields (avoid clash with Alice keywords);
2007-02-26 ago removed obsolete eq_set;
2007-01-26 ago exported interface for explicit error messages
2007-01-25 ago added explicit query function for arities to subalgebra projection
2006-12-29 ago classes: more direct way to achieve topological sorting;
2006-12-29 ago ``classes`` now returns classes in topological order
2006-09-18 ago classes: maintain serial number;
2006-09-04 ago proper project_sort
2006-09-01 ago project_algebra yields sort projector
2006-08-17 ago added all_super_classes
2006-07-03 ago project_algebra: norm_sort;
2006-06-27 ago added class projection
2006-05-16 ago abstract interfaces for type algebra;
2006-05-07 ago tuned;
2006-05-05 ago added class_error and exception CLASS_ERROR (supercedes DOMAIN);
2006-05-02 ago tuned;
2006-05-02 ago added domain_error;
2006-05-01 ago arities: maintain original codomain;
2006-04-30 ago moved certify_class/sort to type.ML;
2006-04-27 ago tuned basic list operators (flat, maps, map_filter);
2006-04-25 ago added remove_sort;
2006-04-11 ago removed superclasses (see sign.ML);
2006-04-10 ago removed unused class_le_path, sort_less;
2006-02-06 ago TableFun: renamed xxx_multi to xxx_list;
2005-12-17 ago sort_distinct;
2005-10-04 ago minor tweaks for Poplog/ML;
2005-09-15 ago TableFun/Symtab: curried lookup and update;
2005-09-01 ago curried_lookup/update;
2005-08-29 ago use AList operations;
2005-08-28 ago added superclasses, class_le_path
2005-07-19 ago tuned norm_sort, mg_domain;
2005-06-29 ago removed obsolete eq_sort, mem_sort, subset_sort, eq_set_sort, ins_sort, union_sort, rems_sort;
2005-06-15 ago (undone experimental changes)
2005-06-15 ago subclassing done
2005-03-03 ago Move towards standard functions.
2005-02-13 ago Deleted Library.option type.
2004-06-21 ago added certify_class/sort;
2004-06-05 ago tuned comments;
2004-05-29 ago improved output; refer to Pretty.pp;
2004-05-21 ago incorporate sort ops from term.ML; use Graph.T; misc cleanup;
2000-07-07 ago inter_sort: keep normal!
1999-09-29 ago mg_domain: exception DOMAIN;
1999-07-23 ago replace assoc lists by Symtab.table;
1997-10-06 ago now uses Syntax.simple_str_of_sort;
1997-08-06 ago added str_of_classrel;
1997-04-18 ago removed least_sort;
1997-04-16 ago Type classes and sorts (isolated from type.ML).