Reserved Words

  Class(y) defines a number of system classes. Some of these have names
  which may conflict with other names in your application, specifically
  Class and Object. If your application defines functions or classes with
  these names, you will need to modify your application accordingly. Most
  other Class(y) system classes have names which have been qualified by a
  three-letter prefix such as CSY or CMS, so they should not conflict with
  other class or function names. See the System Classes section for more
  information.

  It is also unwise to use the scalar class names Array, Block, Character,
  Date, Integer, Logical, Nil, and Numeric, since these class names are used
  by standard Clipper, and some of them, such as Array and NIL, are Clipper
  reserved words.

  Reserved Message Names

  The Class and Object classes define a number of messages which are
  inherited by other classes in the system. Some of these, such as those
  covered in the Predefined Messages section, should not be used as
  message names elsewhere. However, others can be overridden, as with any
  inherited method. Overriding inherited system methods should be done with
  caution, since it could lead to compatibility problems when used with
  classes written by other people.

  Clipper Reserved Words

  Clipper reserved words cannot be used as method names, but they can be
  used as message names. To define a method with the same name as a Clipper
  reserved word, use the MESSAGE...METHOD command. See the Clipper
  documentation for a full list of reserved words.