[DFDL-WG] still no need for fn:error - re-assess
Mike Beckerle
mbeckerle.dfdl at gmail.com
Wed Aug 3 09:53:15 EDT 2016
It would certainly be valuable to throw an SDE as well as a PE. When
unparsing there isn't much diffierence since both are fatal, but when
parsing it's quite important.
I suppose we could use the QName argument as a means of distinguishing
these two types of error?
...mikeb
Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
www.tresys.com
Please note: Contributions to the DFDL Workgroup's email discussions are
subject to the OGF Intellectual Property Policy
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On Wed, Aug 3, 2016 at 5:34 AM, Steve Hanson <smh at uk.ibm.com> wrote:
> Agreed that fn:error() looks suitable. Is the assumption that it always
> throws a PE, or do we want the ability to throw an SDE as well ?
>
> I ask because section 23 maps all but one XPath error to SDE.
>
> Regards
>
> Steve Hanson
> *IBM Integration Bus*
> <http://www-03.ibm.com/software/products/en/ibm-integration-bus>,
> Hursley, UK
> Architect, *IBM DFDL*
> <http://www.ibm.com/developerworks/library/se-dfdl/index.html>
> Co-Chair, *OGF DFDL Working Group* <http://www.ogf.org/dfdl/>
> *smh at uk.ibm.com* <smh at uk.ibm.com>
> tel:+44-1962-815848
> mob:+44-7717-378890
>
>
>
> From: Mike Beckerle <mbeckerle.dfdl at gmail.com>
> To: Steve Hanson/UK/IBM at IBMGB
> Cc: "dfdl-wg at ogf.org" <dfdl-wg at ogf.org>
> Date: 06/07/2016 14:02
> Subject: Re: [DFDL-WG] still no need for fn:error - re-assess
> ------------------------------
>
>
>
> I recall now that QName is a subtype of string, so it's just a kind of
> string.
>
>
> So I agree. I guess fn:error can be used as per XPath without modification.
>
> Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
> *www.tresys.com* <http://www.tresys.com/>
> Please note: Contributions to the DFDL Workgroup's email discussions are
> subject to the *OGF Intellectual Property Policy*
> <http://www.ogf.org/About/abt_policies.php>
>
>
> On Wed, Jul 6, 2016 at 5:32 AM, Steve Hanson <*smh at uk.ibm.com*
> <smh at uk.ibm.com>> wrote:
> Mike
>
> True that xs:QName is not a type that is supported as the simple type of
> an element, but we do use QNames elsewhere in DFDL schema, eg, in element
> refs, type references, as the type of some DFDL properties (eg, dfdl:ref,
> dfdl:hiddenGroupRef, dfdl:prefixLengthType), to reference variables in
> expressions, ... So I don't see a problem with having a function argument
> being a QName.
>
> Regards
>
> Steve Hanson
> *IBM Integration Bus*
> <http://www-03.ibm.com/software/products/en/ibm-integration-bus>,
> Hursley, UK
> Architect, *IBM DFDL*
> <http://www.ibm.com/developerworks/library/se-dfdl/index.html>
> Co-Chair, *OGF DFDL Working Group* <http://www.ogf.org/dfdl/>
> *smh at uk.ibm.com* <smh at uk.ibm.com>
> tel:*+44-1962-815848* <%2B44-1962-815848>
> mob:*+44-7717-378890* <%2B44-7717-378890>
>
>
>
> From: Mike Beckerle <*mbeckerle.dfdl at gmail.com*
> <mbeckerle.dfdl at gmail.com>>
> To: Steve Hanson/UK/IBM at IBMGB
> Cc: "*dfdl-wg at ogf.org* <dfdl-wg at ogf.org>" <*dfdl-wg at ogf.org*
> <dfdl-wg at ogf.org>>
> Date: 05/07/2016 19:08
> Subject: Re: [DFDL-WG] still no need for fn:error - re-assess
> ------------------------------
>
>
>
>
> So the fn:error() XPath function takes a problematic argument.
>
> All the arguments are optional, so fn:error() is legal.
>
> The first argument is of type xs:qQName, and we don't have that type in
> DFDL. So the best we could do is to accept a string that is in the "form"
> of a QName, e.g.,
> "foo:bar".
>
> The second argument is a description string, third and subsequent args are
> objects. The manner by which this string and objects are provided to the
> execution environment is implementation dependent according to the XQuery
> and XPath spec, and this is fine for DFDL implementations also.
>
> The lack of the QName type for the first argument suggests we're going to
> need to create dfdl:error(string, string, item()*), where the first
> argument is a string in the form of a QName, and the other arguments are as
> per fn:error.
>
>
> Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
> *www.tresys.com* <http://www.tresys.com/>
> Please note: Contributions to the DFDL Workgroup's email discussions are
> subject to the *OGF Intellectual Property Policy*
> <http://www.ogf.org/About/abt_policies.php>
>
>
> On Tue, Jul 5, 2016 at 11:49 AM, Steve Hanson <*smh at uk.ibm.com*
> <smh at uk.ibm.com>> wrote:
> WG agreed that an error function is needed, action 288 raised.
>
> *No*
> *Action *
>
> *288*
> *Decide on error function specification (Mike)*
> 5/7: An error function is useful for expressions when unparsing. Mike to
> evaluate XPath fn:error().
>
>
> Regards
>
> Steve Hanson
> *IBM Integration Bus*
> <http://www-03.ibm.com/software/products/en/ibm-integration-bus>,
> Hursley, UK
> Architect, *IBM DFDL*
> <http://www.ibm.com/developerworks/library/se-dfdl/index.html>
> Co-Chair, *OGF DFDL Working Group* <http://www.ogf.org/dfdl/>
> *smh at uk.ibm.com* <smh at uk.ibm.com>
> tel:*+44-1962-815848* <%2B44-1962-815848>
> mob:*+44-7717-378890* <%2B44-7717-378890>
>
>
>
> From: Mike Beckerle <*mbeckerle.dfdl at gmail.com*
> <mbeckerle.dfdl at gmail.com>>
> To: "*dfdl-wg at ogf.org* <dfdl-wg at ogf.org>" <*dfdl-wg at ogf.org*
> <dfdl-wg at ogf.org>>
> Date: 14/06/2016 17:10
> Subject: Re: [DFDL-WG] still no need for fn:error
> Sent by: "dfdl-wg" <*dfdl-wg-bounces at ogf.org*
> <dfdl-wg-bounces at ogf.org>>
> ------------------------------
>
>
>
> I want to re-open the discussion of fn:error.
>
> Previously we said it was not needed because an assert could be used.
>
> However, we've now run into where we want to cause an error, during
> unparsing, during outputValueCalc.
>
> <xs:element name="Protocol" type="pcap:bit" dfdl:length="8"
> dfdl:outputValueCalc="{
> if (fn:exists(../../pcap:ICMPv4)) then 1
> else if (fn:exists(../../pcap:TransportLayer/pcap:TCP )) then 6
> else if (fn:exists(../../pcap:TransportLayer/pcap:UDP )) then 17
> else -1 }"/>
>
> That -1 at the end. That's an error case. We really want
> fn:error("Unrecognized protocol.")
>
> We can't change to a dfdl:assert, because assertions aren't evaluated when
> unparsing.
>
> Comments?
>
> Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
> *www.tresys.com* <http://www.tresys.com/>
> Please note: Contributions to the DFDL Workgroup's email discussions are
> subject to the *OGF Intellectual Property Policy*
> <http://www.ogf.org/About/abt_policies.php>
>
>
> On Thu, Jul 25, 2013 at 9:16 AM, Mike Beckerle <*mbeckerle.dfdl at gmail.com*
> <mbeckerle.dfdl at gmail.com>> wrote:
> Respin of this example:
>
> Here's the example as suggested by Jonathan of how to issue an error that
> I previously was suggesting needed fn:error. I'm convinced this is
> sufficient and we can avoid the need for fn:error now.
>
> <xs:element name="magic_number" type="ex:uint32"
> dfdl:byteOrder="bigEndian">
> <xs:annotation>
> <xs:appinfo source="*http://www.ogf.org/dfdl/*
> <http://www.ogf.org/dfdl/dfdl-1.0/>">
> <dfdl:assert
> test="{ (xs:unsignedInt(.) eq *dfdl:unsignedInt('xa1b2c3d4')*) |
> (xs:unsignedInt(.) eq *dfdl:unsignedInt('xd4c3b2a1')*) }"
> message="{ fn:concat(
> 'Magic number ',
> dfdl:hexBinary(dfdl:unsignedInt(.)),
> ' was not 0xA1B2C3D4 (for bigEndian) or 0xD4C3B2A1
> (for littleEndian).' }" />
> <dfdl:setVariable ref="ex:bOrd">{ xs:unsignedInt(.) }<dfdl:setVariable>
> </xs:appinfo>
> </xs:annotation>
> </xs:element>
>
>
> On Wed, Jul 24, 2013 at 11:58 AM, Steve Hanson <*smh at uk.ibm.com*
> <smh at uk.ibm.com>> wrote:
> Mike, I think you meant:
>
> test="{ (xs:unsignedInt(.) eq *dfdl:unsignedInt('xa1b2c3d4')*) |
> (xs:unsignedInt(.) eq *dfdl:unsignedInt('xd4c3b2a1')*) }"
>
>
> Regards
>
> Steve Hanson
> Architect, IBM Data Format Description Language (DFDL)
> Co-Chair, *OGF DFDL Working Group* <http://www.ogf.org/dfdl/>
> IBM SWG, Hursley, UK
> *smh at uk.ibm.com* <smh at uk.ibm.com>
> tel:*+44-1962-815848* <%2B44-1962-815848>
>
>
>
> From: Mike Beckerle <*mbeckerle.dfdl at gmail.com*
> <mbeckerle.dfdl at gmail.com>>
> To: *dfdl-wg at ogf.org* <dfdl-wg at ogf.org>,
> Date: 24/07/2013 16:46
> Subject: [DFDL-WG] still no need for fn:error
> Sent by: *dfdl-wg-bounces at ogf.org* <dfdl-wg-bounces at ogf.org>
> ------------------------------
>
>
>
> Here's the example as suggested by Jonathan of how to issue an error that
> I previously was suggesting needed fn:error. I'm convinced this is
> sufficient and we can avoid the need for fn:error now.
>
> <xs:element name="magic_number" type="ex:uint32"
> dfdl:byteOrder="bigEndian">
> <xs:annotation>
> <xs:appinfo source="*http://www.ogf.org/dfdl/*
> <http://www.ogf.org/dfdl/dfdl-1.0/>">
> <dfdl:assert
> test="{ (xs:unsignedInt(.) eq *dfdl:unsignedInt('xa1b2c3d4')*) |
> (xs:unsignedInt(.) eq *dfdl:unsignedInt('xd4c3b2a1')*) }"
> message="{ fn:concat(
> 'Magic number ',
> dfdl:hexBinary(dfdl:unsignedInt(.)),
> ' was not 0xA1B2C3D4 (for bigEndian) or 0xD4C3B2A1
> (for littleEndian).' }" />
> <dfdl:setVariable ref="ex:bOrd">{ xs:unsignedInt(.) }<dfdl:setVariable>
> </xs:appinfo>
> </xs:annotation>
> </xs:element>
>
>
> --
> Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
> *www.tresys.com* <http://www.tresys.com/>
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>
>
> --
> Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
> *www.tresys.com* <http://www.tresys.com/>
>
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> Unless stated otherwise above:
> IBM United Kingdom Limited - Registered in England and Wales with number
> 741598.
> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
>
>
>
> Unless stated otherwise above:
> IBM United Kingdom Limited - Registered in England and Wales with number
> 741598.
> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
>
>
>
> Unless stated otherwise above:
> IBM United Kingdom Limited - Registered in England and Wales with number
> 741598.
> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU
>
>
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