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Re: XPath to identify a point in an XML document (Was: A sort of synthesis)

From: Claudius Teodorescu <claudius.teodorescu@gmail.com>
Date: Tue, 12 Mar 2013 10:21:40 +0200
Message-ID: <CAPTZ0Vw_eG1XFo1QNEQStvVjoTQddxvEXGAjeOVhwry4D-bquQ@mail.gmail.com>
To: Dennis Hamilton <dennis.hamilton@acm.org>
Cc: liam@w3.org, Casey Jordan <casey.jordan@jorsek.com>, "public-change@w3.org" <public-change@w3.org>

I am thinking about an EXPath module with function(s) about text content
ranges (among others), to solve the problem of pointing for the changes of
the text content.

I can help with editing/maintaining it, as I am currently doing this for
some other EXPath modules [1].


[1] http://extxsltforms.sourceforge.net/expath-specs/index.html

On Tue, Mar 12, 2013 at 5:24 AM, Dennis E. Hamilton <dennis.hamilton@acm.org
> wrote:

> @Liam,
> Yes, all of those things can be done with XPath unadorned.  But being able
> to inspect or even match or substring a text item in a formula is not the
> same as directing a path into the node that holds the text.  Ditto for
> pointing into the values of attributes, something that can be relevant for
> the kind of lengthy attribute values that store spreadsheet cell formulas,
> for example.  I should perhaps been more emphatic about "find a path."
> I did wonder about those wonderful manipulations on the types of values in
> nodes, but I couldn't reconcile that with setting a path except for
> search-condition predicates.  I think those just help filter us to an
> intended node (and avoiding unintended ones).  Getting to that last inch,
> extending the path into the text (or attribute value) node itself, seems to
> require augmentation of some kind.
> I'm fine with that.  If there's some way that plain XPath can cross that
> gap, I'm very interested.  And I'm not disturbed by the need to augment
> XPath, since there is need for other augmentation anyhow.
>  - Dennis
> PS: Aside to @Casey.  Although ODF spreadsheet cells don't have their
> coordinates in the element for the cell, ones for OOXML spreadsheets do,
> and that makes for great XPath access.  I sympathize with the numeric
> compactness desire.  For the document formats I work with, that battle was
> lost long ago [;<).
> I do find it interesting that it is easy to keep numerically-stepped path
> sequences sorted in XML-document scan order.  That makes it rather easy to
> match up change-tracking operations with their targets in the XML, at least
> to the element level.  I don't know if it is a help or a hindrance when
> editing.  I suspect the tracked-change paths are best recomputed whenever a
> modified document is persisted.  But the simplicity of match-up on opening
> a document for viewing or editing is something to look into.
> -----Original Message-----
> From: Liam R E Quin [mailto:liam@w3.org]
> Sent: Monday, March 11, 2013 16:55
> To: dennis.hamilton@acm.org
> Cc: 'Innovimax W3C'; public-change@w3.org
> Subject: RE: XPath to identify a point in an XML document (Was: A sort of
> synthesis)
> On Mon, 2013-03-11 at 15:07 -0700, Dennis E. Hamilton wrote:
> [...]
> > It appears that XPath can find a text node, but not a path to the
> > interior of that text node.  (A text node is a string and never has
> > adjacent text nodes -- it is the largest string that can be made
> > without crossing a tag.)
> It depends what you mean by "find" - it can return a substring; XPath 2
> (and 3) can return a (node, offset) pair if you like.
> >   XPath, even abbreviated XPath can be far "wordier" but it can also
> > be simpler because it can short-circuit using full paths because it is
> > based on a search model, not a strictly-navigational model.
> SoftQuad Panorama, years ago, used the nearest element ancestor with an
> ID attribute, if there was one, and navigated from there, since IDs tend
> to be relatively stable across document revisions.
> > For example, one advantage of an (augmented) XPath arrangement is the
> > ability to find attributes via XPath.  This means that one can find
> > elements by known xml:id attribute values.
> Yes, indeed.
> >  There are other aspects of XPath usage that might be used  easier to
> > confirm that the target has what is expected there (sort of the way
> > patch software often works).
> Yes, one can also use contains() to check for a string, for example.
> Liam
> --
> Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/
> Pictures from old books: http://fromoldbooks.org/
> Ankh: irc.sorcery.net irc.gnome.org freenode/#xml
Received on Tuesday, 12 March 2013 08:22:10 UTC

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