March 2005 - dfdl-wg - lists.ogf.org

Fw: [dfdl-wg] alternate syntax for DFDL annotations
by Suman Kalia 02 Mar '05

02 Mar '05

Hi Mike -- We will be creating XML schema to model our annotations and the attributes applicable to the representation of a particular element/type will be grouped within the complex type of the annotation schema. My preference will be use annotation approach consistently in DFDL. Moreover the attributes defined in the compact form are not easily accessible from the XML Schema APIs, you have to look into the DOMNode associated with the XSDElementDeclaration to get access to such attributes; it makes the programming task a little harder. Having said that SOAP encoded schemas use this compact form to identify the type and dimensions of the array types; some folks like this approach and some hate it.. Suman Kalia IBM Toronto Lab WebSphere Business Integration Application Connectivity Tools Tel : 905-413-3923 T/L 969-3923 Fax : 905-413-4850 Internet ID : kalia(a)ca.ibm.com ----- Forwarded by Suman Kalia/Toronto/IBM on 03/02/2005 12:38 PM ----- Mike Beckerle <mike.beckerle(a)ascentialsoftware.com> Sent by: owner-dfdl-wg(a)ggf.org 03/01/2005 03:53 PM To dfdl-wg(a)gridforum.org cc Subject [dfdl-wg] alternate syntax for DFDL annotations Up til now we've considered DFDL annotations only as inside the appinfo context. However, we should consider whether we should use non-native attributes as well or as an alternative: E.g., simple DFDL rep properties could also be expressed like this: <xs:element name="foo" type="xs:string" dfdl:repType="text" dfdl:charset="UTF-8" dfdl:repLength="10"/> This has the advantages of compactness, and is a fully supported way of extending XML Schema. That is, using non-native attributes is a supported extension idiom. This won't handle things that really need the syntactic support of element structure to express their complexity, e.g., things like specifying text delimiters with quoting and escape-sequence specifications. For those we'll still need to open an appinfo annotation up. However, for basic things like byteOrder and such it is far more attractive syntactically to use non-native attributes than appinfo annotations. Comments? ...mikeb

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RE: [dfdl-wg] alternate syntax for DFDL annotations
by Myers, James D 02 Mar '05

02 Mar '05

I agree - I think I like #2. I know at one point in the past we had complaints when we tried to use attributes with namespaces - it may just have been that parsers weren't dealing with them correctly early on. Whatever it was, option 2 would provide a work around as well as helping us keep a single 'canonical' form for DFDL. Jim > -----Original Message----- > From: owner-dfdl-wg(a)ggf.org [mailto:owner-dfdl-wg@ggf.org] On > Behalf Of Martin Westhead > Sent: Wednesday, March 02, 2005 12:16 PM > To: Mike Beckerle > Cc: dfdl-wg(a)gridforum.org > Subject: Re: [dfdl-wg] alternate syntax for DFDL annotations > > > Hi Mike, > > This is interesting I wasn't aware you could do this. My > concern would > be if it turned out the schema tools couldn't handle it but I > tried XML > Spy which seems to just ignore the extra annotations. > > So I'd be happy to use them. As you point out we will need both these > and annotations so we are left with a choice. Either we: > > 1. Specify some (most) dfdl additions in this non-native attribute > form and use annotations when required or > > 2. We specify everything as annotations but allow this form as a > systematic short hand. > > I think I prefer (2). The sort of thing I have in mind is making the > annotation syntax look like: > > <xs:element name="foo" type="xs:string"> > <annotation> > <appinfo> > <dfdl:attributes dfdl:repType="text" > dfdl:charset="UTF-8" > dfdl:repLength="10"/> > </appinfo> > <annotation > </xs:element> > > And then this be directly equivalent (and trivially transformed > into/from) what you had before: > > <xs:element name="foo" > type="xs:string" > dfdl:repType="text" > dfdl:charset="UTF-8" > dfdl:repLength="10"/> > > I'm not sure if it matters that much but it seems like it might be > neater if everything could be represented in the same form. > > Also there may be times when you would like to use the > annotation form > because you have a bock of stuff that could be reused multiple times. > Once your annotations have become attributes in the main > schema they are > more intimately tied to it. > > Cheers, > > Martin > > > > Mike Beckerle wrote: > > Up til now we've considered DFDL annotations only as inside the > > appinfo > > context. However, we should consider whether we should use > non-native > > attributes as well or > > > > as an alternative: E.g., simple DFDL rep properties could also be > > expressed like this: > > > > <xs:element name="foo" > > > > type="xs:string" > > > > dfdl:repType="text" > > > > dfdl:charset="UTF-8" > > > > dfdl:repLength="10"/> > > > > > > > > This has the advantages of compactness, and is a fully > supported way > > of > > extending XML Schema. That is, using non-native attributes is a > > supported extension idiom. This won't handle things that > really need the > > syntactic support of element structure to express their complexity, > > e.g., things like specifying text delimiters with quoting and > > escape-sequence specifications. For those we'll still need > to open an > > appinfo annotation up. However, for basic things like > byteOrder and such > > it is far more attractive syntactically to use non-native > attributes > > than appinfo annotations. > > > > > > Comments? > > > > ...mikeb > > > >

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DFDL call notes
by Myers, James D 02 Mar '05

02 Mar '05

FYI - quick notes about a short call today - Steve, Tara, and I hung out on the DFDL call today for about 20 minutes to see if we'd get a quorum. We didn't. We noted that the availability of the prototype from Ascential seems to be a pre-requisite for further discussions about the reader/writer/filter/function ideas and resolving the issues around transform versus sub-type centric approaches. (I'm glad its not me in the critical path this time!) In any case, I think we agreed that we need the prototype, or some description of it, soon to get the discussion moving again and make another productive f-2-f possible. Jim

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alternate syntax for DFDL annotations
by Mike Beckerle 02 Mar '05

02 Mar '05

Up til now we've considered DFDL annotations only as inside the appinfo context. However, we should consider whether we should use non-native attributes as well or as an alternative: E.g., simple DFDL rep properties could also be expressed like this: <xs:element name="foo" type="xs:string" dfdl:repType="text" dfdl:charset="UTF-8" dfdl:repLength="10"/> This has the advantages of compactness, and is a fully supported way of extending XML Schema. That is, using non-native attributes is a supported extension idiom. This won't handle things that really need the syntactic support of element structure to express their complexity, e.g., things like specifying text delimiters with quoting and escape-sequence specifications. For those we'll still need to open an appinfo annotation up. However, for basic things like byteOrder and such it is far more attractive syntactically to use non-native attributes than appinfo annotations. Comments? ...mikeb

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How to handle multi-dimensional arrays
by mike.beckerle＠ascentialsoftware.com 02 Mar '05

02 Mar '05

We have come up with an approach to how to represent multi-dimensional arrays within XSD-described XML. The attached test file (.xml) and DFDL Schema (.dfdl.xsd) illustrate the proposed solution. The proposal does not require any changes to XSD, XML or any other special constructs outside of a single dfdl annotation to specify the storage order of the representation. I'm pretty happy with how this works out. We can handle arrays with different storage orders, like fortran style column-major vs. more common row-major, and it dovetails nicely with XPath expressions and the XSD data model. Schema validation can really do something for you, like tell you if you have all the elements of the array (if it's fixed size), and that you don't have multiple elements occupying the same array location. Those interested in multi-dimensional array support please give this some consideration. That said, I'm departing on vacation for a week, so I'll toss this out there for people to look at, but I won't be able to interact with you all on it until I get back. ...mikeb

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