RE: [xml] Substitution of nested entity references

["Henke, Markus" <Markus_Henke ordat com>]

> -----Original Message-----
> From: Daniel Veillard [mailto:veillard redhat com]
> Sent: Wednesday, April 10, 2002 6:03 PM
> To: Henke, Markus
> Cc: 'xml gnome org'
> Subject: Re: [xml] Substitution of nested entity references
>
>
> On Wed, Apr 10, 2002 at 05:24:25PM +0200, Henke, Markus wrote:
> > Maybe i've expressed myself unclear. The already built tree contains
> > XML_ENTITY_REF_NODEs as part of content of element nodes or 
> attribute
> > values. As above mentioned, e.g. a call to xmlGetProp() on such an
> > attribute
> > (e.g. <aElement aAttr="Text &i_contain_an_entity_ref; MoreText" />)
> > results in something like
> > value = "Text &i_am_a_nested_entity_ref; MoreText"
> > which isn't the expected result.

> <cut />
 
>   So it should *not* return a value = "Text 
> &i_am_a_nested_entity_ref; MoreText"
> value ! And a simple script check confirms this:
>
> paphio:~/XML -> python
> Python 1.5.2 (#1, Jul  5 2001, 03:02:19)  [GCC 2.96 20000731 
> (Red Hat Linux 7.1 2 on linux-i386
> Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
> > > > import libxml2
> > > > doc = libxml2.parseFile("tst.xml") 
> > > > root = doc.getRootElement()
> > > > print root.prop("aAttr")
> Text content MoreText
 
Now i see! We talk at cross purposes resp. have different
ideas of "nested entity references".
Try your check with a document like

=============================================================
<?xml version="1.0" encoding="iso-8859-1" standalone="yes" ?>

<!DOCTYPE aElement [
  <!ELEMENT aElement ANY>
  <!ATTLIST aElement aAttr CDATA #REQUIRED>
  <!ENTITY aNestedEnt "i_am_a_nested_entity">
  <!ENTITY aEnt "&aNestedEnt;">
]>

<aElement aAttr="Text &aEnt; MoreText">
  Content &aEnt; MoreContent
</ aElement>
=============================================================

You'll get "> Text &aNestedEnt; MoreText" !!!
*That's* what i talk about all the time... 8)


> > > So why are you trying to remove them. No really I can't 
> understand.
> > I wouldn't too, but i don't try to do so.
> > I want to accumulate the (useful) content of the different node
> > types (as child nodes of an entity declaration) with regard to the
> > case where the child node again is an entity reference (and do a
> > recursive call to xmlResolveEntityRef() in that case).
> > It's all about to enable routines like xmlGetProp(),
> > xmlNodeGetContent(), ... to result in a *complete* substitution
> > of an entity reference. 
>
>   Okay, so you're just gathering content of the subtree. It seems to
> me that xmlNodeGetContent() does just this. the only change which may
> be needed is to change the handling of XML_ENTITY_REF_NODE 
> nodes to recurse
> in the node->children when the node found is such an entity ref.

Yep, at the moment it just gathers "ent->content", where "ent" is 
the corresponding entity declaration, it doesn't care about what
child nodes (e.g. nested entity refs) the declaration includes.
Therefore xmlNodeGetContent() has an similar behavior as xmlGetProp().
With an xml document like the one above you'll get

  xmlNodeGetContent(xmlDocGetRootElement(docPtr)))
  == "Content &aNestedEnt; MoreContent";

which IMHO isn't correct (resp. not what i would've expected).

Maybe you could revise my approach under this new perspective
(provided that i'm right and we've talked at cross purposes
before)?
 
> Daniel

Thanx again, Markus