-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Jim Fulton wrote: > On Sep 26, 2007, at 3:37 PM, Dieter Maurer wrote: > >> Jim Fulton wrote at 2007-9-26 15:10 -0400: >>> ... >>>> Jim Fulton wrote at 2007-9-26 11:29 -0400: >>>>> ... >>>>>> IFoo(x) >>>>>> IBar(multi=(x,y)) >>>>> Actually, that is not the case. If x already provides IFoo, >>>>> then in >>>>> the first case, the existing object is retuned. Nothing is >>>>> instantiated. OTOH, in: >>>>> >>>>> getMultiAdapter([x], IFoo) >>>>> >>>>> or >>>>> getAdapter(x, IFoo) >>>>> >>>>> either there is an error or some factory will be called. x >>>>> won't be >>>>> returned unless the factory happens to return it. >>>> Is this not an irrelevant implementation detail? >>> No, the specified behavior is different. >> Hm. But "getAdapter" and "getMultiAdapter" may return "x" as well >> (when the factory decides to do this). >> >> Thus, why is it relevant? > > Because they don't take into account what x already provides. They > will always call some factory. Also, they never call __conforms__.
Why does the caller care? She just wants an object which will provide the 'IFoo' contract on behalf of the passed context. If 'x' is capable of providing 'IFoo' without help, then failing (or worse, returning a less-specific factory result) when calling 'getAdapter' is the Wrong Thing (a "least surprise" violation, if nothing else). Tres. - -- =================================================================== Tres Seaver +1 540-429-0999 [EMAIL PROTECTED] Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFG+wLR+gerLs4ltQ4RAuojAJ90QTKCzaEonLYPTqmJ+5SJpz1eDwCgyy4K w59LMYo7ur+GCfEwAy+w5aM= =Weg9 -----END PGP SIGNATURE----- _______________________________________________ Zope3-dev mailing list Zope3-dev@zope.org Unsub: http://mail.zope.org/mailman/options/zope3-dev/archive%40mail-archive.com
