Regards Steve Hanson Architect, IBM DFDL Co-Chair, OGF DFDL Working Group IBM SWG, Hursley, UK smh@uk.ibm.com tel:+44-1962-815848 ----- Forwarded by Steve Hanson/UK/IBM on 11/08/2015 16:27 ----- From: Michele Zundo <michele.zundo@esa.int> To: Mike Beckerle <mbeckerle.dfdl@gmail.com> Cc: Steve Hanson/UK/IBM@IBMGB, Maurizio De Bartolomei <Maurizio.De.Bartolomei@esa.int>, Montserrat Piñol <mpinol@eopp.esa.int>, "Rui Mestre (DME)" <rui.mestre@deimos.com.pt> Date: 18/05/2015 08:47 Subject: Re: [DFDL]: First Release of DFDL4S Parser Library Thanks Mike, we will add this to our list to be considered/noted. However reading your explanation (NB I’m NOT at all an XPath expert) it seemed you had some good reason for avoiding longer than 1 path, so I would like to avoid our DFDL4S project results in an over-complication of the DFDL implementation/use of Xpath unless there are other reasons/users/rationale requiring this feature. (btw the syntax is still weird-ish: “intersect” reminds me of Venn Diagrams…) As a project manager I always evaluate solutions and their cost vs the benefit they bring, and I believe the DFDL community should keep this is mind. Michele PS The syntax above anser to the question “belongs to” , would there be any way to express ranges of values then ? On 15 May 2015, at 16:24 , Mike Beckerle <mbeckerle.dfdl@gmail.com> wrote: Just a few comments on DFDL4S, and also thank you to Michele and team for the presentation on Tuesday. I think all the issues in the spreadsheet are fairly easily fixed in that they are not major changes to DFDL4S, and would bring it into much closer compliance with the DFDL spec. The exception is the XPath limitations where DFDL4S has gone beyond what XPath 2.0 allows and invented new syntax for expressing set membership requirements. So I took a look, and XPath 2.0 has a set intersect operator: ns1 intersect ns2 => ns3 This isn't in DFDL today, but might be usable to achieve the set membership test; however, it requires use of XPath node sequences of length greater than 1, which DFDL has avoided mostly. I say mostly as there are XPath expressions that return node sequences of length greater than 1 and those can be arguments to fn:count(...) for example. So far in DFDL such node sequences cannot "leak out" of the XPath expression into DFDL elements, and I think the usage in DFDL4S is similar in that these node sequences would be needed only to check for set membership, so the result is just a boolean as part of an assert/discriminator. We should examine whether XPath 2.0 set intersection is enough to meet the need. I believe the expressions would be something like: fn:exists( . intersect (123, 456, 789, .... many more items....) ) - mike beckerle 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 On Tue, May 12, 2015 at 10:45 AM, Michele Zundo <michele.zundo@esa.int> wrote: for reference, here a summary of the reported problem in an excel sheet. This message and any attachments are intended for the use of the addressee or addressees only. The unauthorised disclosure, use, dissemination or copying (either in whole or in part) of its content is not permitted. If you received this message in error, please notify the sender and delete it from your system. Emails can be altered and their integrity cannot be guaranteed by the sender. Please consider the environment before printing this email. ----------------------------------------- Michele Zundo Head of Ground System Definition and Verification Office EOP-PEP European Space Agency, ESTEC e-mail: michele.zundo@esa.int ----------------------------------------- Michele Zundo Head of Ground System Definition and Verification Office EOP-PEP European Space Agency, ESTEC e-mail: michele.zundo@esa.int This message and any attachments are intended for the use of the addressee or addressees only. The unauthorised disclosure, use, dissemination or copying (either in whole or in part) of its content is not permitted. If you received this message in error, please notify the sender and delete it from your system. Emails can be altered and their integrity cannot be guaranteed by the sender. Please consider the environment before printing this email. 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