Chris Withers wrote:
Philipp von Weitershausen wrote:
...hence the quotes. It's a "function" in that I want to use it as an
adapter that doesn't need to be instantiated by a factory before
being used.
All adapters need to be instantiated.
Why?
def myStrAdapter(something):
return str(something)
This function adapts strings to integers,
(the other way around)
why would it need to be instantiated?
It instantiates a 'str' object. The 'str' object is the adapter for
'something'. 'myStrAdapter' is the adapter factory.
No. You always register a factory which is called upon lookup. That's
because adapters are context-dependent and thus need to be
instantiated every time you look them up.
What if they're not context-dependent as in my example above?
Then what's the point of an adapter? An adapter factory is supposed to
take at least one argument (context) = the object that it adapts. An
adapter that doesn't adapt anything is, per definitionem, not an adapter.
ultimately, I'm looking to replace code like the following:
convertors = {
int:{str:str,datetime:datetime},
str:(int:int,datetime:datetime},
}
def convert(x,y):
return convertors[type(x)][type(y)](x)
...if you see what I mean. Apologies for the trivial examples, but these
are real problems...
Why not leave it? No need to bend over too hard for solving everything
with the CA :).
--
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