"""
@volatile decerator for storing objects in memory

usage is as follows:

from game.gamesrc.parents.rhns.volatile import volatile

class VolatileCow:
    def __init__(self, scriptlink):
        self.scriptlink = scriptlink
        self.name = "Betsy"

class CowStall(AnEvenniaObject):
    @volatile
    def cow(self):
        return VolatileCow(self.scripted_obj)
"""
def volatile(func):
    _memo = {}
    def _memoized(scriptlink, *args):
        id = (scriptlink.scripted_obj.id,func.__name__)
        if id in _memo:
            return _memo[id]
        else:
            return _memo.setdefault(id, func(scriptlink, *args))
    return property(fget=_memoized)