[Zope] Acquisition mysteries

[Rik Hoekstra]

> -----Original Message-----
> From: stoermer@migserv.augsburg.mig.net
> [mailto:stoermer@migserv.augsburg.mig.net]On Behalf Of Heiko Stoermer
> Sent: Wednesday, August 25, 1999 3:13 PM
> To: Rik Hoekstra
> Subject: Re: [Zope] manage_clone problem
>
>
> thanks a lot, the PARENTS[0] expression solved my problem.
> I you have time: could you, in short, explain to me why that worked?
> (yes, I am a newbie...)
>
> Greetings,
> Heiko



OK, I'll try, though it's complicated, and I do not completely understand
myself.... Given the following folder structure:

root - DTML Method
  |    DTML Document
  |
current folder



The famous acquisition 'enables' an object to call a property from a parent
object as if it were its own. If you use a DTML Method the calling object is
the folder that you call from (current folder in the example), because the
DTML method 'acts' as if it were only a property of the current folder. So
if you call manage_clone from a DTML Method it 'thinks' it is called from
the current folder. It then 'clones' the object to the current folder.
A DTML Document, however, is an object of its own, and it can't contain
other object. So if you call manage_clone from a DTML Document it will try
to clone it to  itself, and *for one reason or another* ends up with the
folder it's called from. Apparently acquisition thinks that is its nearest
parent... Could someone with fuller understanding of acquisition explain
this??? Is this a bug or a feature?

If you add a <dtml-with expr="PARENTS[0]"> the object manage_clone is not
called from the DTML Document, but from its nearest parent, which is the
folder in the context of which it is called (current folder in the example).
This works (at least for me) as expected, but why this parent is not found
automatically escapes me...

Rik


>
> Rik Hoekstra wrote:
>
> > To:                     Zope Mailing List <zope@zope.org>
> > Subject:                [Zope] manage_clone problem
> >
> > > I have created a DTML Document in the root directory that is
> supposed to
> > > be used from all subdirs of my web application.
> > > This document contains a call to manage_clone(), which should copy an
> > > object from some other folder into the _current_ folder.
> > > But as the DTML is stored in the root directory, manage_clone always
> > > clones into the _rootdir_, too.
> > >
> > > this is the call:
> > > <!--with "manage_clone(foo.bar,'new_id',REQUEST)"-->
> > >
> >
> > I have done something very similar, with success. I only used a DTML
> > method to do the manage_cloning. As this seems to be a namespace
> > issue, you could try to change to a DTML method or perhaps a
> > <dtml-with "PARENTS[0]"> would help.
> >
> > Rik Hoekstra
> >
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>
> --
> Heiko Stoermer
> MIG Augsburg
>
>
>
>