On Thursday 28 February 2008 23:17:14 Michael Bayer wrote:

okay, if u say so. (therefore in my case i have to know if there's a trigger pending to simulate a missing value. not very clean..)

any other similar contracts?

ok, so u need the method pop() to be there, and do exactly what plain dict does.

let me do a draft:

class dict4attr_storage_protocol: 'required methods of the state.dict's usage-protocol'

def has_key( self, sk): 'return True if present, else False' raise NotImplementedError __contains__ = has_key

def __getitem__( self, key, *defaultvalue): '''return value of that key if found else if defaultvalue present, return that else raise KeyError ''' raise NotImplementedError

def get( self, key, defaultvalue =None): return self.__getitem__( key, defaultvalue)

def __setitem__( self, key, value): '''store value for key''' raise NotImplementedError

def __delitem__( self, key): '''delete value for key''' raise NotImplementedError

def pop( self, key, *defaultvalue): '''if key found, remove it and return its value else if defaultvalue present, return that else raise KeyError ''' raise NotImplementedError

for example having has_key AND __contains__ being same, is redundant.

contract for triggerring: trigger checks for key in state.dict via (contains?haskey?getitem?get?) and fires if not found.

contract for ... any other specific behaviours that may have some influence into the dict itself...

etc..... is this making sense?