Re: [Exist-development] default context in functions

[Dmitriy S. <sha...@gm...>]

Note: There are functions like fn:string or fn:base-uri that "... In the
zero-argument version of the function, $arg defaults to the context
item. That is, calling fn:string() is equivalent to calling
fn:string(.). ..."

The question "why" didn't get answer ...

-- 
Cheers,

Dmitriy Shabanov

On Wed, 2010-07-21 at 13:23 +0200, James Fuller wrote:
> noticed a few irregularities in my original posting, for the sake of
> clarity I will summarise:
> 
> as expected, this works
> --------------------------------------------------------------------
> 
> declare function local:test($arg){
> name($arg)
> };
> 
> let $a := <test><a></a><b/></test>
> return
> local:test($a)
> 
> --------------------------------------------------------------------
> 
> then we have
> 
> --------------------------------------------------------------------
> 
> declare function local:test(){
> name()
> };
> 
> let $a := <test><a></a><b/></test>
> return
> $a/local:test()
> 
> --------------------------------------------------------------------
> 
> which works, and I can see the sense of it, as we are using the xpath
> to set context, but can't find the 'words' in the specs that allow
> this.
> 
> similarly
> 
> --------------------------------------------------------------------
> 
> declare function local:test(){
> name(.)
> };
> 
> //*/local:test()
> 
> --------------------------------------------------------------------
> 
> but what is defo not conformant is something like
> 
> --------------------------------------------------------------------
> 
> declare function local:test(){
> //*
> };
> 
> local:test()
> 
> --------------------------------------------------------------------
> 
> which just arbitrarily gives function access to db root context.
> 
> a few thoughts as I am occupied working on other stuff at the moment
> but will scan the specs soon:
> 
> * does an unadorned function, e.g. without being in an explicit xpath
> actually have a default context always supplied ? e.g. is local:test()
> shorthand for /./local-test() or something of the kind ?
> 
> * is context passed via xpath e.g. //$arg/local:test() or
> //*/local:test() ok, seems to invalidate what is said in the XQuery
> section 3.1.5
> 
> * as a lot of existing xquery code (mine included) wil break with this
> change, as suggested we need both an exist option and a util function
> to switch behaviors and have default configured as to how things work
> now. For those who want more conformant behavior or more security on
> the context that a function is allowed can switch this default
> configuration