"""
    Miscellaneous utilities
"""

import functools

class LazyProperty (property) :
    """
        Lazy-loaded properties
    """

    def __init__ (self, func) :
        """
            Initialize with no value
        """

        super(LazyProperty, self).__init__(func)

        self.value = None

    def run (self, obj) :
        """
            Run the background func and return the to-be-cached value
        """

        return super(LazyProperty, self).__call__(obj)
 
    def get (self, obj) :
        """
            Return the cached value
        """

        xxx
    
    def set (self, obj, value) :
        """
            Set the cached value
        """

        xxx

    def test (self, obj) :
        """
            Tests if a value is set
        """

        xxx
       
    def __call__ (self, obj) :
        """
            Return the cached value if it exists, otherwise, call the func
        """

        if self.test(obj):
            # generate it
            self.set(obj, self.run(obj))

        return self.get(obj)

class LazyIteratorProperty (LazyProperty) :
    """
        A lazy-loaded property that automatically converts an iterator/genexp into a list.
    """

    def run (self, obj) :
        """
            Wrap LazyProperty.run to return a list
        """

        return list(super(LazyIteratorProperty, self).run(obj))

lazy_load = LazyProperty
lazy_load_iter = LazyIteratorProperty