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[Bug 5795] Static Typing: CVS: K2-Steps-2, K2-FunctionProlog-14

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Date: Mon, 30 Jun 2008 09:01:03 +0000
To: public-qt-comments@w3.org
Message-Id: <E1KDFFv-0006U7-QX@wiggum.w3.org>

http://www.w3.org/Bugs/Public/show_bug.cgi?id=5795


Tim Mills <tim@cbcl.co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|FIXED                       |




--- Comment #18 from Tim Mills <tim@cbcl.co.uk>  2008-06-30 09:01:03 ---
In Bug 5810, Michael Dyck has confirmed that 

fs:item-at(fn:error(), Expr) 

can be rewritten as the empty sequence by virtual of its static type.

"I don't see how that holds. I'd say that just because an expression raise an
error, doesn't make it ok to rewrite to function fn:error."

This can all be proved without actually performing a rewrite to fn:error.

$fs:dot has type none (because it is an error).

>From FS. statEnv |-  axis Axis of none : none

So $fs:dot/child::e is also of type none.

fs:item-at( $fs:dot/child::e (of type none), 928) is empty

Any expression of type empty can be rewritten as the empty sequence.


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