#chapter Executable Objects

This chapter deals with objects that can be executed.  As XPCE defines
both send-operations and get-operations, code is divided into two major
groups: *procedures*, as represented by class code and various subclasses,
succeed or fail when executed and *functions* as represented by class
function which yield a value.  Functions may be used as procedures.

The table below gives a brief overview of the classes in this chapter:

	code		Superclass.  General aspects of code objects.
	message		Send operation
	if		Branches
	while		Loops
	and		Compound procedure and logical operator
	or, not		logical operator
	=, <, >, =<, >=	Arithmetic comparison operators
	block		Compound procedure
	==, \==		Equality test
	@=		Assignment of references (`object ->name_reference')
	function	General aspects of functions
	quote_function	As the LISP ' operator
	?		Get operation
	create		Create new objects (`class <-instance')
	progn		Compound function
	when		Conditional function
	+, -, *, /	Arithmetic operators
	var		Variables (chapter Variables)

#end chapter

#class code
#end class

#class message
#end class

#class if
#end class

#class while
#end class

#class and
#end class

#class or
#end class

#class not
#end class

#class binary_condition
#end class

#class =
#end class

#class <
#end class

#class >
#end class

#class =<
#end class

#class >=
#end class

#class block
#end class

#class ==
#end class

#class \==
#end class

#class @=
#end class

#class function
#end class

#class quote_function
#end class

#class ?
#end class

#class progn
#end class

#class when
#end class

#class create
#end class

#class binary_expression
#end class

#class +
#end class

#class -
#end class

#class *
#end class

#class /
#end class