Re: [Zope] Black Magic

2000-10-11 Thread Robin Becker

In article 00e801c032ea$50b15970$[EMAIL PROTECTED], Evan Simpson
[EMAIL PROTECTED] writes
From: Fred Yankowski [EMAIL PROTECTED]
 The information you just provided about the DTML Method "call
 signature" and the like is very useful.  Is this kind of reference
 material written down somewhere in a guide/how-to/wiki/...?

The only thing I could find offhand is
http://www.zope.org//Wikis/DevSite/Projects/PythonMethods/NamespaceObjectInterfa
ce, which I wrote.
I don't know if ZDP or someone else has documented it.

Cheers,

Evan @ digicool  4-am
OK so I have a similar but still to me confusing problem

I have a Product P containing two folderish ZClasses A and B. A and B
both have class specific methods A_init and B_init to initialise
specific bits of each. The product P has some methods eg M defined which
are useful to both A and B.

1) How do I make the add methods behave identically whether I invoke
as /dir/manage_addProduct/P/A_add or when I invoke from the manage add
interface. I want to know the meta_type of the actual location where the
product will appear not the factory's meta_type.

2) When I attempt to call B_add from inside A's private method A_init
I seem to see a completely different context from when I call B_add
directly on an instance of A.

3) I suppose this is related to the fact that inside A_init (the private
method) I don't seem to see the same context as in A_add, ie the method
M is visible in A_add, but not in A_init.

How do ZClass contexts and the product context relate?
-- 
Robin Becker

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Re: [Zope] Black Magic

2000-10-10 Thread Chris Withers

Pierre-Julien Grizel wrote:
 It seems that in fact the DTML document doesn't actually pass _.None and
 _ to my object. WHY ??

This is deep voodoo that I don't fully understand. To me, it appears
that what you get depends on how your __call__ was called...

The arguments vary dependign on whether:
-you were called from a bit of DTML
-traversed directly through a URL
-called from soem python you wrote

Maybe someone from DC could shed some light on 'the rules' or point us
to soem documentation?

cheers,

Chris

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Re: [Zope] Black Magic

2000-10-10 Thread Evan Simpson

From: Chris Withers [EMAIL PROTECTED]
 Pierre-Julien Grizel wrote:
  It seems that in fact the DTML document doesn't actually pass _.None and
  _ to my object. WHY ??

 This is deep voodoo that I don't fully understand. To me, it appears
 that what you get depends on how your __call__ was called...

 The arguments vary dependign on whether:
 -you were called from a bit of DTML
 -traversed directly through a URL
 -called from soem python you wrote

Here's the scoop:

1. DTML Methods' __call__ signature is (client=None, REQUEST={}, RESPONSE=None, **kw). 
 The client,
REQUEST, and keyword arguments are layered to form the namespace for the Method, with 
the keywords
on top, then the client, then REQUEST.

2. If you call a DTML Method in a Python expression, its namespace will be empty 
unless you
explicitly pass a client, REQUEST, and/or keyword arguments.

3. URL traversal automatically tries to look up parameter names in the REQUEST.  Both 
REQUEST and
RESPONSE are found in REQUEST, so they are passed to the Method.

4. When an object is named in the name attribute of a DTML tag, the DTML code checks 
to see whether
the object is callable and has a true attribute called "isDocTemp".  If so, it passes 
the namespace
to the REQUEST parameter.  Otherwise, if the object is callable it calls it with no 
arguments.
Thus, to simulate dtml-var foo in Python code, including DTML expressions, you must 
either use
"obj(_.None, _)" or "obj(REQUEST=_)".

Cheers,

Evan @ digicool  4-am


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Re: [Zope] Black Magic

2000-10-10 Thread Fred Yankowski

Evan,

The information you just provided about the DTML Method "call
signature" and the like is very useful.  Is this kind of reference
material written down somewhere in a guide/how-to/wiki/...?

I tried to figure out the call signature of a Python method by having
the called function use just "(*varargs, **kwargs)" as formal
parameters, but the inscrutable mapply() function seems to thwart that
effort as mapply() adjusts the function call according to what
parameters the called function (or callable object, ...) expects.
Very weird.  Is there some document that covers the how and why of
mapply()? 

On Tue, Oct 10, 2000 at 11:17:13AM -0400, Evan Simpson wrote:
 1. DTML Methods' __call__ signature is (client=None, REQUEST={},
 RESPONSE=None, **kw).  The client, REQUEST, and keyword arguments
 are layered to form the namespace for the Method, with the keywords
 on top, then the client, then REQUEST.  ...

-- 
Fred Yankowski   [EMAIL PROTECTED]  tel: +1.630.879.1312
Principal Consultant www.OntoSys.com   fax: +1.630.879.1370
OntoSys, Inc 38W242 Deerpath Rd, Batavia, IL 60510, USA

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Re: [Zope] Black Magic

2000-10-10 Thread Evan Simpson

From: Fred Yankowski [EMAIL PROTECTED]
 The information you just provided about the DTML Method "call
 signature" and the like is very useful.  Is this kind of reference
 material written down somewhere in a guide/how-to/wiki/...?

The only thing I could find offhand is
http://www.zope.org//Wikis/DevSite/Projects/PythonMethods/NamespaceObjectInterface, 
which I wrote.
I don't know if ZDP or someone else has documented it.

Cheers,

Evan @ digicool  4-am


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