Storing empties

[Aahz]

In article <1h5bepj.q0sqsnbqqgjrN%aleax at mail.comcast.net>,
Alex Martelli <aleax at mail.comcast.net> wrote:
>Aahz <aahz at pythoncraft.com> wrote:
>> In article <1h58k4p.12xd7rj1t5peh0N%aleaxit at yahoo.com>,
>> Alex Martelli <aleaxit at yahoo.com> wrote:
>>>
>>>the canonical idiom when you need such distinction is:
>>>
>>>_not_there = object()
>>>def foo(bar=_not_there, baz=_not_there, bap=_not_there):
>>>    if bar is _not_there: ...
>>>
>>>Other unique objects can be substituted for the 'sentinel', but I prefer
>>>an empty "object()" because it has no other possible meaning except that
>>>of a distinguishable, identifiable sentinel.  IOW, you could set the
>>>_not_there name to [] or {} or many other things, but that could be
>>>slightly confusing for the reader (since the other things might have
>>>other meanings and purposes) while 'object()' shouldn't be.
>> 
>> What's your preferred idiom when you're dealing with storable objects?
>
>What's a "storable object"?  You mean, something that can be pickled, or
>passed to the .write method of a file object, or stored in a database,
>or what else?

Pickled and/or stored in a DB.
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

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