early plans to an XML Editor -- questions

[Wilbert Berendsen <wbsoft xs4all nl>]

Hi, all, I'me new here and have just some ideas and questions.

I would like to start a project to write an XML editor (I have a name
already, but no single line of code yet and not much experience) but
I would like to get some feedback. First I'll try to outline what I
think of:

* opens file with or without dtds
* edit any sort of xml file
* fast (simple gui)
* use dtd or Xschema to help easy creation of new valid documents
* use xsl to transform documents (to (x)html or latex or csv or
  whatever)
* use xsl to combine documents (like writing a letter to multiple
  recipients, or constructing a website from xsl templates)
* editing in different modes:
  * tree view / no-nonsense plain-text view.
  * a LyX-like (WYSIWYM) screen view. (my xml editor will be
    primarily intended to construct structured web
    documents/books(docbook) etc.) This view should also be helpful
    to enter structured data like addressbook lists, etc. The Widget
    could use CSS to have a basic useful layout.

My questions:

* is there a gtk/gnome widget that I could use to render XML using (a
  subset  of) CSS (primarily 'display:' property and some
  font-size/font-family thinghies) so that the user can edit
  documents in a WYSIWYM way?
  Maybe I must use Mozilla (no experience in that) but I would like
  to  have something lighter and simpler)? Abiword's widget??
* Are there already any efforts towards a XML editor/document
  processor? (Not that I found, besides the number of projects that
  use xml)
* would this be a nice, useful tool or could I better put some energy
  in helping exsisting projects akin this one.

Thanks,
Wilbert

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