Python 2.2 property sub-classes
 
This package provides a hierarchy of Python 2.2 property classes
for use in a wide range of applications.
 
Rationale:
 
        [About Python 2.2 Properties]
 
        The built in property type assumes that the user will define two or
        three functions for every property to store, retrieve, and/or delete
        the particular property.  For example:
 
                class X(object):
                        def seta( self, value ):
                                self.__dict__['an'] = int(value)
                        def geta( self):
                                return self.__dict__['an']
                        def dela( self ):
                                del self.__dict__['an']
                        a = property( geta,seta,dela,"A simple property a" )
 
        In this approach, a property object is considered to be a way
        of organizing "accessor methods" so that the accessor methods
        will be triggered by standard python attribute access mechanisms.
        
        This is obviously useful in many situations where particular
        property values require custom code for each of their accessor
        methods.  Unfortunately, the approach tends to require considerable
        extra code for every property so defined.  Where properties
        are highly customized and different from each other this is
        acceptable, as the code would need to be written somewhere.
 
        [About basicproperty Properties]
 
        In many real world applications, however, most of the properties
        defined are not radically different from other properties
        within the application.  Instead, the properties tend to share
        most of their semantics and needs.  Furthermore, there are common
        patterns in property usage which tend to be shared across
        applications.
 
        The basicproperty package defines a framework for creating families
        of properties for use in real world applications.  These properties
        provide basic implementations of most features needed for simple
        data modeling applications, for instance:
 
                bounds checking -- automatic checking of data values against
                        defined bounds objects, with appropriately raised errors
                        
                optional coercion -- allows you to define property classes
                        which can modify given data types to match the property's
                        required data types (particularly useful in GUI
                        applications)
 
                optional method-name-based accessors -- to allow for functionality
                        similar to the built-in property type, while maintaining
                        the features of the basicproperty properties.  This
                        functionality, however, allows for redefining client
                        accessor methods by simple subclassing and overriding.
 
                optional default values -- either static or calculated for
                        use when a particular property is not currently defined
 
                propertied object class -- an object sub-class explicitly
                        designed for use with basicproperty property objects
                        providing a default __init__ function to automatically
                        assign values to defined properties from named
                        arguments.
 
        The end goal of the package is to reduce the amount of code needed
        to write applications which want to model complex data types using
        consistent property classes.  In practice, this goal seems to be met,
        though the early-alpha status of the project means that there are
        still considerable areas for improvement.

Package Contents
		__init__ -- Python 2.2 property sub-classes basic -- Core property classes common -- Commonly used property types defaults -- Holders for property default values/functions ext (package) -- extension-specific property classes linearise -- Object for linearizing a node-graph to XML propertied -- Generic services for propertied objects standard (package) -- Old pure-Python property types tests (package) -- Testing package for basicproperty weak -- Mix-in providing weakref-based storage for properties xmlencoder

Data
		__path__ = [r'p:\properties\basicproperty']