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Dieter Maurer wrote:
> George Lee wrote at 2006-3-11 00:41 -0500:
>>What is the difference between Implicit and Acquirer? Between Explicit
> 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).
>>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
> 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".
Perhaps the distinction is that 'Impleict' and 'Explicit' are the names
of mixin classes, whose '__of__' method returns an 'ImplicitAcquirer' /
'ExplicitAcquirer' wrapper (respectively). The wrapper is what does the
actual majyk which Dieter describes.
Tres Seaver +1 202-558-7113 [EMAIL PROTECTED]
Palladion Software "Excellence by Design" http://palladion.com
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