ConditionClass define the hierarchy of conditions
as carried by Condition instances. Conditions classes could be real
tom classes, but the features provided by said mechanism are too
baroque for this purpose---only the inheritance is needed.
The tom condition class hierarchy does not employ multiple inheritance.
TOM conditions are evidently modelled after CL.
instance (id) with instance (id) super_condition name ByteString name;
id super_condition;
condition is nil.
public ByteString name;
protected id init id sc name ByteString nm;
boolean isConditionSuper id other;
other is a super condition class of the receiving
condition class.