Re: [xml-dev] Concerned about the increasing reliance on XPath

[Philip Fearon <pgfearo@googlemail.com>]

On Mon, May 9, 2011 at 7:45 PM, Stephen D Green
<stephengreenubl@gmail.com> wrote:
> On 9 May 2011 18:52, Philip Fearon <pgfearo@googlemail.com> wrote:
>> Yes, it seems each vendor has adopted their own 'harness' for setting
>> the XPath evaluation context so that saved XPaths are portable.
>
> Yes, but this highlights my issue; they are portable *within instances of
> that implementation and not (as much as we'd like) between implementations*
>
True. To mitigate the portability issue, SketchPath can use
user-supplied XSLT to transform the XPath files to a suitable format,
or directly to code like c#, for example.
>
>>
>> SketchPath's approach is to create grouped sets of XPath expressions
>> that are saved in simple XML files so they can be reused easily as a
>> resource in other applications.
>> (These same XML files are also used to set parameters and processor
>> settings for an XSLT test tool).
>>
>> As well as the XPath itself, additional metadata is stored for each expression:
>> 1. A name for the expression - other expressions can use this name to
>> reuse the expression as a variable
>> 2. An XPath identifying the context node for evaluation
>> 3. A descriptive comment
>
> Yes, my interest has been in Tamelizer (GoogleCode project) and this
> does the same
>
I hadn't heard of this, I will look it up.
>>
>
>
> Maybe there would be more portability if your XML language could
> also allow every group to inlude the bindings though, like this:
>
>             <cwb:group name="alpha">
>                <cwb:expression name="header-1">
>                    <cwb:namespace-declarations>
>                        <cwb:expression name="spec">
>                            <cwb:main>'http://expath.org/ns/xmlspec'</cwb:main>
>                            <cwb:comment>Created: 09/05/2011
> 18:18:45</cwb:comment>
>                        </cwb:expression>
>                    </cwb:namespace-declarations>
>                    <cwb:main>/spec/header</cwb:main>
>                    <cwb:comment>Created: 09/05/2011 18:16:13</cwb:comment>
>                </cwb:expression>
>            </cwb:group>
>
I will look into this, though experience with XML tells us that using
local namespace declarations can cause maintenance issues later. As
there's a special 'global' XPath group, there could be a set of global
namespaces and potentially a set for each group. Currently, different
files are used for different namespace sets.