[DFDL-WG] Parsing Rules for resolving points of uncertainty
DFDL
mbeckerle.dfdl at gmail.com
Tue Oct 6 17:30:51 CDT 2009
I am not sure about schema def errors caught at runtime. I think these
are more serious and shouldn't cause backtracking. I don't think they
should just convert to processing errors.
Consider that some dfdl implementarions may not detect anything until
runtime.
...mikeb
On Oct 6, 2009, at 5:44 PM, Tim Kimber <KIMBERT at uk.ibm.com> wrote:
>
> - I'd like to see a version in which the comments are addressed and
> removed.
> - typo in para 1 : 'neatest'
> - 'A point of uncertainty is caused'. Probably better to say that it
> is 'opened' or 'started'.
> - para which begins 'For an optional element' has a repeated phrase
> towards the end.
> - I was assuming that any processing error, of any kind, relating to
> any physical region, would cause backtracking to the nearest point
> of uncertainty.
> If there is any set of processing errors that *doesn't* cause
> backtracking, that set should be described in this doc.
> - Should have a statement about how validation errors affect points
> of uncertainty. I'm assuming that they don't ( either the parse is
> immediately stopped by the host application, or the validation error
> is ignored)
> - Should have a statement about how schema definition errors, if
> detected by the DFDL parser, affect points of uncertainty. I'm
> assuming that they are treated exactly like a processsing error, and
> cause backtracking to occur in the normal way.
>
> regards,
>
> Tim Kimber, Common Transformation Team,
> Hursley, UK
> Internet: kimbert at uk.ibm.com
> Tel. 01962-816742
> Internal tel. 246742
>
>
>
> From: dfdl-wg-request at ogf.org
> To: dfdl-wg at ogf.org
> Date: 06/10/2009 18:18
> Subject: dfdl-wg Digest, Vol 38, Issue 2
>
>
>
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> Today's Topics:
>
> 1. DFDL Specification draft v1.036 available (Alan Powell)
> 2. Parsing Rules for resolving points of uncertainty V2 (Alan
> Powell)
>
>
> ----- Message from Alan Powell <alan_powell at uk.ibm.com> on Tue, 6
> Oct 2009 14:46:36 +0100 -----
> To:
> dfdl-wg at ogf.org
> Subject:
> [DFDL-WG] DFDL Specification draft v1.036 available
>
>
>
> Draft 036 of the DFDL Specification V1 is available but
> unfortunately sourceforge seems to be having problems again so I
> cannot upload it. If you need a copy please send me an email.
>
> Alan Powell
>
> MP 211, IBM UK Labs, Hursley, Winchester, SO21 2JN, England
> Notes Id: Alan Powell/UK/IBM email: alan_powell at uk.ibm.com
> Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898
>
>
>
>
> 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
>
>
>
>
>
>
>
>
> ----- Message from Alan Powell <alan_powell at uk.ibm.com> on Tue, 6
> Oct 2009 18:16:59 +0100 -----
> To:
> dfdl-wg at ogf.org
> Subject:
> [DFDL-WG] Parsing Rules for resolving points of uncertainty V2
>
>
>
> Updated proposal based on comments
>
>
>
>
> Alan Powell
>
> MP 211, IBM UK Labs, Hursley, Winchester, SO21 2JN, England
> Notes Id: Alan Powell/UK/IBM email: alan_powell at uk.ibm.com
> Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898
>
> ----- Forwarded by Alan Powell/UK/IBM on 06/10/2009 18:15 -----
> From: Steve Hanson/UK/IBM
> To: Tim Kimber/UK/IBM at IBMGB
> Cc: Alan Powell/UK/IBM at IBMGB, Suman Kalia/Toronto/IBM at IBMCA, Mike
> Beckerle <mbeckerle.dfdl at gmail.com>, Peter Lambros/UK/IBM at IBMGB, steve.marting at progeny.net
> Date: 30/09/2009 10:31
> Subject: Re: Parsing Rules for resolving points of uncertainty
> (speculative parsing)
>
>
>
>
> Some more comments in here.
>
> Steve copied in as will be discussed on call today.
>
> [attachment "Resolving Uncertainty v1.doc" deleted by Alan Powell/UK/
> IBM]
>
> Regards
>
> Steve Hanson
> Programming Model Architect, WebSphere Message Brokers,
> OGF DFDL WG Co-Chair,
> Hursley, UK,
> Internet: smh at uk.ibm.com,
> Phone (+44)/(0) 1962-815848
>
> From: Tim Kimber/UK/IBM
> To: Mike Beckerle <mbeckerle.dfdl at gmail.com>
> Cc: Alan Powell/UK/IBM at IBMGB, Suman Kalia <kalia at ca.ibm.com>, Peter
> Lambros/UK/IBM at IBMGB, Robert Connolly <rconnoll at us.ibm.com>, Steve
> Hanson/UK/IBM at IBMGB
> Date: 28/09/2009 14:20
> Subject: Re: Parsing Rules for resolving points of uncertainty
> (speculative parsing)
>
>
>
>
> re: Mike's point, I would suggest
> - member of a choice group/unordered group/group containing floating
> elements: scope of uncertainty is the scope of the element
> - optional occurrence : parser tries first to parse another
> occurrence, and the scope of uncertainty is the scope of the
> element. Secondly, parser tries to parse the item following the
> element ( which may be a group ) and the scope of uncertainty is the
> scope of that element/group.
>
> re: Alan's draft, I think the final para could be replaced with the
> following two statements:
> - if a processing error is encountered while parsing an option, the
> parser will back up and try the next option. If there are no further
> options, the processing error will propagate out to the next
> enclosing point of uncertainty.
> - a dfdl:assert can be used to trigger a processing error. If the
> expression evaluates to false, the parser will behave exactly as if
> a normal processing error had been encountered.
>
> Wording can probably be improved...
>
> regards,
>
> Tim Kimber, Common Transformation Team,
> Hursley, UK
> Internet: kimbert at uk.ibm.com
> Tel. 01962-816742
> Internal tel. 246742
>
>
>
> From: Mike Beckerle <mbeckerle.dfdl at gmail.com>
> To: Alan Powell/UK/IBM at IBMGB
> Cc: Steve Hanson/UK/IBM at IBMGB, Tim Kimber/UK/IBM at IBMGB, Robert
> Connolly <rconnoll at us.ibm.com>, Peter Lambros/UK/IBM at IBMGB, Suman
> Kalia <kalia at ca.ibm.com>
> Date: 25/09/2009 21:53
> Subject: Re: Parsing Rules for resolving points of uncertainty
> (speculative parsing)
>
>
>
>
>
> Some feedback attached.
>
> We need some notion of the region of uncertainty, so we can discuss
> where assertions and discriminators have effect, and so we can say
> when the uncertainty ends and we no longer consider backtracking
> that region just because we finished without processing error.
>
>
>
> On Fri, Sep 25, 2009 at 11:51 AM, Alan Powell
> <alan_powell at uk.ibm.com> wrote:
>
> Guys (limited distribution initially)
>
>
> I have simplified the previous speculative parsing description into
> a set of simple rules.
>
> Discussion points
> 1. Deemed to be found rule 1 'All the components of the
> option are found' could severely limit the ability to do partial
> parsing as it includes everything up to the terminator.
> 2. Do all/more the processing errors need to be listed for
> Not Found rule 3?
>
>
>
>
> Alan Powell
>
> MP 211, IBM UK Labs, Hursley, Winchester, SO21 2JN, England
> Notes Id: Alan Powell/UK/IBM email: alan_powell at uk.ibm.com
> Tel: +44 (0)1962 815073 Fax: +44 (0)1962 816898
>
>
>
> 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
>
>
>
>
>
> [attachment "Resolving Uncertainty v1.doc" deleted by Tim Kimber/UK/
> IBM]
>
> [attachment "Resolving Uncertainty v1.doc" deleted by Steve Hanson/
> UK/IBM]
>
>
>
>
>
> 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
>
>
>
>
>
> [attachment "Resolving Uncertainty v2.doc" deleted by Tim Kimber/UK/
> IBM] --
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