@chapter Class Group
@cindex class group
All classes belong to the @dfn{class group}.
The subset of classes beloging to same class group has similar interfaces.

@table @code

@item Allocator class group
@findex allocator, allocator class group
Dynamic allocated memory operation class.
The class belong to the allocator class group operate one or more memory
objects which allocated dynamically.
The class in this group is used by set class group etc @dots{}

@item Math class group
@findex Math, Math class group
Mathematical operation of objects and expression object handling class.

@item TextForm class group
@findex TextForm, TextForm class group
Formatter classes for plain text data.
The TextForm class group supports indentation of text.

@item XML class group
@findex XML, XML class group

@end table

