Re: [Zope] UNEXPECTED: Acquisition.Explicit may acquire implicitly
Pierre-Julien Grizel writes: > Dieter Maurer wrote: > > > > This implies, that the idiom > > > > > > > > cannot be used safely to test, whether "o" has attribute > > itself (rather than acquired it). > > We probably should have a standard function for this kind > > of test. > > > > Mhhh Something like "" ? "aq_base" is not considered safe and unavailable in DTML. But you are right, that would be the implementation of the function, I call for. Dieter ___ Zope maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope-dev )
Re: [Zope] UNEXPECTED: Acquisition.Explicit may acquire implicitly
Dieter Maurer wrote: > > While trying to understand, what the "bself= self.aq_explicit" > in "OFS.DTMLMethod.__call__" should do, I detected an unexpected > behaviour: > > usually, this "bself" acquires implicitly from > its container (though not from its context) > > More precisely: > > if "bself.aq_self" is itself an implicit acquisition > wrapper, the "bself.aq_explicit" acquires implicitly > from "bself.aq_self.aq_parent". > > The following Python module demonstrates the behaviour: > > --- > from Acquisition import Implicit > > class C(Implicit): pass > > b= C() > b.i= 0 > b.d= C() > b.h= C() > > e_bd= b.d.aq_explicit > try: > e_bd.i > print 'e_bd implicitly acquired i' > except AttributeError: pass > > e_bhd= b.h.d.aq_explicit > try: > e_bhd.i > print 'e_bhd implicitly acquired i' > except AttributeError: pass > --- > > At first, I thought this were a bug. > At second thought, however, it appears to be quite > natural, though unexpected: > > if o is self.__of__(parent), then > getattr(o.aq_explicit,k) = getattr(self,k).__of__(o) > > If "self" is an implicit wrapper itself, > then acquisition may be used to look up "k". > > This implies, that the idiom > > > > cannot be used safely to test, whether "o" has attribute > itself (rather than acquired it). > We probably should have a standard function for this kind > of test. Mhhh Something like "" ? P.-J. > > Dieter > > ___ > Zope maillist - [EMAIL PROTECTED] > http://lists.zope.org/mailman/listinfo/zope > ** No cross posts or HTML encoding! ** > (Related lists - > http://lists.zope.org/mailman/listinfo/zope-announce > http://lists.zope.org/mailman/listinfo/zope-dev ) -- If the only tool you have is a hammer, you tend to see every problem as a nail. Si le seul outil dont vous disposez est un marteau, vous avez tendance à voir chaque problème comme un clou. --Abraham Maslow ___ Zope maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope-dev )
[Zope] UNEXPECTED: Acquisition.Explicit may acquire implicitly
While trying to understand, what the "bself= self.aq_explicit" in "OFS.DTMLMethod.__call__" should do, I detected an unexpected behaviour: usually, this "bself" acquires implicitly from its container (though not from its context) More precisely: if "bself.aq_self" is itself an implicit acquisition wrapper, the "bself.aq_explicit" acquires implicitly from "bself.aq_self.aq_parent". The following Python module demonstrates the behaviour: --- from Acquisition import Implicit class C(Implicit): pass b= C() b.i= 0 b.d= C() b.h= C() e_bd= b.d.aq_explicit try: e_bd.i print 'e_bd implicitly acquired i' except AttributeError: pass e_bhd= b.h.d.aq_explicit try: e_bhd.i print 'e_bhd implicitly acquired i' except AttributeError: pass --- At first, I thought this were a bug. At second thought, however, it appears to be quite natural, though unexpected: if o is self.__of__(parent), then getattr(o.aq_explicit,k) = getattr(self,k).__of__(o) If "self" is an implicit wrapper itself, then acquisition may be used to look up "k". This implies, that the idiom cannot be used safely to test, whether "o" has attribute itself (rather than acquired it). We probably should have a standard function for this kind of test. Dieter ___ Zope maillist - [EMAIL PROTECTED] http://lists.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope-dev )
