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[www-dom-xpath] <none>

From: <jeroen@tcf.nl>
Date: Fri, 12 May 2000 23:14:48 +0200 (CEST)
Message-Id: <200005122114.XAA05305@webmail2.xs4all.nl>
To: www-dom-xpath@w3.org

Scott wrote:


>> Implementing a specific expression language binding should be optional,
>> with at
>> least 1 of the available expression languages.
>> compare it to DOM which might offer XSL besides CSS.

>  I believe CSS is optional... i.e. the core DOM only consists of basically
>  DOM1.  Can someone on the DOM WG confirm this?  I don't think a DOM
>  implementor should be required to implement any expression language.   (or
>  I might be misunderstanding what you are saying...)

Thats not what I meant, I meant that we should use the same mechanisme as dom 
does where you have a DOM compliance implementation if you implement the core + 
1 of the extended interfaces.

If you split up PAX in a PAX core and expression specific interfaces you can use 
the same mechanisme where an implementation can be DOM-PAX compliant if it has 
implemented f.i. the pax-core and the pax-xpath interfaces. (or pax-core and 
pax-inquirer patterns.. ).


>  the "create" function should be:
>
>    public abstract Expression create(String expression, PrefixResolver
>  prefixResolver)
>      throws ParseException;

ok


>  ExpressionFactory efactory = ExpressionFactory.newInstance("Xpath");
>  Expression expr = efactory.create("foo/baz[yada]", myPrefixResolver);
>  XObject val1 = expr.evaluate(node1, myXEnvironment);
>  XObject val2 = expr.evaluate(node2, myXEnvironment);

Setup is good 
compare it to:
   
   XPathExpression    aExpression = PAXFactory.createXPathExpression();
       or
   InquirerExpression aExpression = PAXFactory.createInquirerExpression();

It sounds more DOMmish in my point of view, and I think it's easier to make it 
language independent. 


>  > Additional features:
>  >
>  > A separate
>  > Expression.parseExpression() DOMException PARSE_EXCEPTION
>  > might be usefull.

>  Given create(String expression, PrefixResolver prefixResolver), do you
>  really think so?

I still think so but you might call it something like "ValidateExpression".
The purpose was not to precompile stuff separately but to validate the 
expression separately without executing it.




>  Do you think more needs to be put on the Inquirer interface, like

>  boolean getBool(String queryString);
>  boolean getMatch(String queryString);

>  ??  It's supposed to be minimal though, so maybe not.  Dunno.

You're asking me ;-), I'm not a minimalist supporter but I think that easyness 
is important.


Best regards,

Jeroen
Received on Friday, 12 May 2000 17:14:56 UTC

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