parsing dates

[Michael Blakeley]

On 2009-10-06 06:44, David Sewell wrote:
> On Mon, 5 Oct 2009, Joe Wicentowski wrote:
>
>> As far as your specific question, you could run a series of "if ($date
>> castable as ...) then ... else" statements on the following datatypes:
>
> [...]
>
>> As an alternative to conditional expressions, I'm not sure if
>> typeswitch would work for this?
>
> typeswitch tests for node kinds, not data types, so the "if castable"
> approach is probably the way to go (barring the custom data type
> solution that Michael mentioned).

I think that's not quite correct. Typeswitch case clauses expect a 
SequenceType, which includes ItemType. So the tests can be any node type 
or any schema type (see http://www.w3.org/TR/xquery/#id-typeswitch and 
http://www.w3.org/TR/xquery/#doc-xquery-SequenceType).

Here's an example: note that the order of the 'case' clauses is 
important. Since xs:ID is derived from xs:string, it must be tested 
before any xs:string test case.

xquery version "1.0-ml";

let $i := "test"
return
   typeswitch ($i)
    case xs:integer return "integer"
    case xs:ID return "id"
    case xs:string return "string"
    default return error((), "UNEXPECTED", $i)

-- Mike