XPath in Scala

Does it make sense to implement full XPath support to native Scala? Why not using one of the existing Java libraries? It's a hard job to develop a fully compliant solution.

The same question should be addressed to other necessaries in the XML environment: xsl, xslt, validation against a schema, DOM like API, ... .

As far as I know we have a native implementation for JAXB (that's great and necessary!) and our own data model (there is some criticism about the actual implementation).

My feeling is that we should have a DSL for XML processing, which acts as a layer to existing Java libraries.

Jürgen



On 08.02.2011 13:35, Marcus Downing wrote:

More than two years ago, I expressed a wish for Scala's native XML to support XPath queries. Looking through the mailing lists and elsewhere, quite a few other people have asked for something similar. Is there any implementation, either out there or under way?

Personally I like the Scala native XML support - with its current limitations.
Ideally it could be extended to wrap up existing Java libraries (so that no DSL is needed) and fully support XPath *2*.

Robert.

Le 8/02/2011 14:48, Juergen Purtz a écrit :

4D5149BA [dot] 8030601 [at] purtz [dot] de" type="cite"> Does it make sense to implement full XPath support to native Scala? Why not using one of the existing Java libraries? It's a hard job to develop a fully compliant solution.

The same question should be addressed to other necessaries in the XML environment: xsl, xslt, validation against a schema, DOM like API, ... .

As far as I know we have a native implementation for JAXB (that's great and necessary!) and our own data model (there is some criticism about the actual implementation).

My feeling is that we should have a DSL for XML processing, which acts as a layer to existing Java libraries.

Jürgen



On 08.02.2011 13:35, Marcus Downing wrote:

More than two years ago, I expressed a wish for Scala's native XML to support XPath queries. Looking through the mailing lists and elsewhere, quite a few other people have asked for something similar. Is there any implementation, either out there or under way?

Does it make sense to implement full XPath support to native Scala? Why not using one of the existing Java libraries? It's a hard job to develop a fully compliant solution.

I agree, if the Java library can be made to integrate with Scala's native XML. I really don't want to go back to the bad old days of verbose API calls to completely mutable data models. (yes, there are occasions when a judicious touch of mutability can help, but it's a long way removed from the old everything-is-mutable way of doing things).
Is there a way of hooking them together?
 

My feeling is that we should have a DSL for XML processing, which acts as a layer to existing Java libraries.

A DSL to ease the use of XPath, yes. An attempt to replicate XPath's functionality with method calls, infix operators, implicits, for comprehensions and special collection types, no - at least not exclusively. XPath is a standard, and it should be possible to copy-paste an XPath between all different languages and libraries. Ideally what I'd like to see is something like this:
   val things = xml \ "/node[id=foo]//thing"



 

Jürgen



On 08.02.2011 13:35, Marcus Downing wrote:

More than two years ago, I expressed a wish for Scala's native XML to support XPath queries. Looking through the mailing lists and elsewhere, quite a few other people have asked for something similar. Is there any implementation, either out there or under way?

Hi All,

I realise this list is effectively dead but wanted to quickly add
something to this (having realised it was the only group I hadn't
migrated to). I have been working on Scales Xml for a while now
(almost ready for a 0.1 release) and this was one of my driving forces
- how hard can it be?

Turns out that the E1/E2 issue is a tough one - E2's context depends
on the context of E1 and not just its evaluation, but the rest works
fairly smoothly. What I've not got is a satisfactory solution to
reverse axis', other than that its very usable already from the
snapshots:

http://code.google.com/p/scala-scales/wiki/ScalesXml

contains a bunch of examples. I'm working on tweaking the site
generation (sbt plugin) before I clean it up a bit more (exceptions on
invalid ncnames, streamwriter - with customisable attribute ordering,
and probably a TreeMap/Set instead of the current ListSet for an
elements attributes).

Cheers,
Chris

Re the E1/E2 problem I'm not giving up but I think getting a base code
out in peoples hands to play with first makes more sense.

On Feb 8, 2:35 pm, Marcus Downing wrote:
> More than two years ago, I expressed a wish for Scala's native XML to
> support XPath queries. Looking through the mailing lists and elsewhere,
> quite a few other people have asked for something similar. Is there any
> implementation, either out there or under way?