Re: [xml] How to know XPath expression return type?

[Daniel Veillard <veillard redhat com>]

On Mon, Sep 12, 2011 at 08:22:20PM +0400, Vladimir B. Grebenschikov wrote:
> Hi 
>
> I want to know return type of XPath expression before evaluation, after expression compilation.
>
> Is it possible? (should be theoretically)
> How ?
>
> Thanks for advice.

 Perfectly right, we should be able to infer this at compilation time,
but I'm afraid we don't. Could be rather simple to add, basically
adding a type to struct _xmlXPathStepOp, fill it in the leaves
and update the result in xmlXPathComp* functions based on the operation
and operands, then add an API to extract to top level value from an
xmlXPathCompExprPtr(). But that doesn't exist ... yet

Daniel

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