[Zope-CMF] Implicit and Acquirer

[George Lee]

Thanks much. It was confusing because the code says certain classes
inherit Implicit, but epydoc shows the class Acquirer.

Other than understanding how Python wraps C classes -- is there anyway
of seeing where the classes are defined, understanding the methods +
method definitions, in a Python-looking way?

Peace,
George




On 3/11/06, Dieter Maurer <dieter at handshake.de> wrote:
> George Lee wrote at 2006-3-11 00:41 -0500:
> > ...
> >What is the difference between Implicit and Acquirer? Between Explicit
> >and Acquirer?
>
> An acquirer is an object with two components "aq_self" and "aq_parent".
> If asked for an attribute, any acquirer passes the request on
> to "aq_self" and returns the result if "aq_self" can deliver
> the attribute.
>
> The difference between an ImplicitAcquirer and an ExplicitAcquirer
> comes only into play when "aq_self" cannot deliver the asked
> for attribute. In this case, an ImplicitAcquirer automatically
> passed the request on "aq_parent" while an ExplicitAcquirer fails
> (with an AttributeError).
>
> >Including, what methods do Implicit and Explicit *add* or *override*?
>
> Both have the same methods (and attribute).
>
> >For instance, does Explicit add an aq_acquire method?
>
> No. But "aq_acquire" is more important for an "ExplicitAcquirer"
> than for an "ImplicitAcquirer":
>
>     "aq_acquire" supports precise control over the lookup
>     behaviour of all kinds of acquirers.
>
>     With an "ExplicitAcquirer", you (usually) must use "aq_acquire"
>     to look the attribute up in "aq_parent"; an "ImplicitAcquirer"
>     would do this automatically (if necessary).
>
> >What else?
>
> Nothing.
>
> >I tried sifting through the C code and the epydoc files but still
> >couldn't make sense of it all -- it seems that Implicit and Acquirer
> >are really the same, for instance. Answers or references would be very
> >appreciated, thanks.
>
> Apparently, you have a reason to use the strange "Implicit and Acquirer"...
>
> In fact, there are two kinds of "Acquirers": "ImplicitAcquirer"
> and "ExplicitAcquirer". There is nothing like "Implicit and Acquirer".
>
>
> --
> Dieter
>