[xquery-talk] flowrrr - how to structure a function?

Per Bothner per at bothner.com
Wed Oct 18 00:49:09 PDT 2006

Martin Probst wrote:
> Per Bothner wrote:
>> Qexo has a function response-header("Name", "value") which returns a
>> "response-header value".  There are no side effects per se.  However,
>> when a response is "serialized" to HTTP by the Qexo servlet any initial
>> response-header value causes the appropriate HTTP response headers to be
>> set.  (A response header value is actually a top-level attribute node.)
> What kind of a result is the "response-header (name?) value" pair? Does 
> it fit into the XQuery data model?

I guess you missed the last sentence you quoted ...

> Using PIs has the benefit that the result is still a well-formed XML 
> document (well, if it was one without the PIs). Also, from my limited 
> understanding of XML in general, I think this is exactly what processing 
> instructions were invented for :-)

PIs would also work.  But attributes work just as well, I think,
and it makes sense: an attribute is a property with a name and a
string value - and a response header is the same thing.

Using PIs would actually be more ambiguous, just because it can
be part of a well-former XML document:  When should be PI be
transmitted as part of the result "body", and when should be
it extracted as a result header?

It doesn't really matter what kind of value is used to represent
the result values, as long as they can be easily distinguished
from the response proper.
	--Per Bothner
per at bothner.com   http://per.bothner.com/

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