functions in XQuery and XPath Data Model 3.0

[James Fuller]

as http://www.w3.org/TR/xpath-datamodel-30/#other-items states the
xpath data model has matured and needs to add 'other types' ... which
have no xml serializations

following on from this statement, I am wondering if the XQuery WG has
considered what could be returned in the following scenario:

let $a := fn:position#0
return
fn:string($a)

it maybe nice to return the name of the function "fn:position" as a
string ... conversely,

let $a := fn:position#0
return
fn:QName($a)

would return the qname of the function.

its probably a stretch to extend this to function arity eg.

let $a := fn:position#0
return
xs:integer($a)

which would return a value of 0.

it may also be useful to expand the description of what functions are
in the data model via fully describing the term 'callable' here
http://www.w3.org/TR/xpath-datamodel-30/#other-items.

James Fuller