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Subject: Re: SV: [plcs-dex] Issue: Use of /IGNORE
Hmm, David, you are saying that the static list of "do-not-use" attributes can be hardcoded into a parser so the value is never read at all, so the value "I am nothing", would never be seen. So, I agree with you: to what purpose are we cluttering up the exchange files with semantically null values that take up 7 bytes per attribute? The only thing I can think of is something like: "A conforming PLCS (DEX?) processor is required to ignore all attributes listed in XXX when reading an exchange file. However, a validating processor may (must?) check that the attributes have a consistent value of '/IGNORE', otherwise an error (warning?) message is logged. Furthermore, upon creating a conforming excahange file, all attributes listed in XXX must be assigned the value '/IGNORE'." Regards, Per-Åke David Price wrote: > All, > > If the DEX specifies that any particular value shall always be exchanged > using something like Identification_assignment rather than the Id attribute, > then it cannot matter whether '/IGNORE', '' or 'Je suis null' is set as the > Id attribute value or not. A conforming post-processor will never look at > that value. > > A simple EXPRESS parser would tell you a mandatory attribute is missing if > nothing were there if it was used to validate the data. Spelling out /IGNORE > for an EXPRESS parser isn't useful - it doesn't understand English. You > might as well reduce the file size by simply using ''. > > Cheers, > David > > > > --------- Original Message -------- > From: Gyllström Leif <leif.gyllstrom@aerotechtelub.se> > To: Per-Åke Ling <per-ake.ling@eurostep.com>, plcs-dex@lists.oasis-open.org > <plcs-dex@lists.oasis-open.org> > Subject: SV: [plcs-dex] Issue: Use of /IGNORE > Date: 23/09/05 10:28 > > >>Yes >> >>See comment below >> >>Leif >> >> >>-----Ursprungligt meddelande----- >>Från: Per-Åke Ling [mailto:per-ake.ling@eurostep.com] >>Skickat: den 23 september 2005 11:12 >>Till: peter.bergstrom@eurostep.com >>Kopia: rob.bodington@eurostep.com; plcs-dex@lists.oasis-open.org >>Ämne: Re: [plcs-dex] Issue: Use of /IGNORE >> >> >>To paraphrase: '/IGNORE' means the attribute should not have been in the > > model at all in the first place, irrespective of whether I have a value > >>for it or no, or even understand the semantics? >> >>In other words, walkig through the model we could statically define the >>attributes that will always carry the value '/IGNORE' in every exchange, > > and no other attributes will ever have the value '/IGNORE'? (Except as a > true data value...) > >><LEIF> Yes ! There is a first draft uploaded to dexlib/docs which >>shows a suggested "static" usage/non-usage of all entity > > attributes.</LEIF> > >> >>Is this correct? >> >>Regards, >>Per-ÅKe Ling >> >>Peter Bergstrom wrote: >>> Do I understand correctly if this means the following: >>> >>> The description attribute on Product is optional. If descriptions are >>> going to be assigned to entities instead of using the attribute > > value, > mainly due to multilingual issues, it then means that all > >>> Product.descriptions must be set to '/GNORE' even though they (as >>> defined now) could just be left out? >>> >>> I think this is polluting the physical files, but it is also slightly >>> more consistent than the current rule, so I will accept it although I > > do > >>> not really see a need to change the current rule. >>> >>> Peter Bergström >>> >>> >>> -----Original Message----- >>> *From:* Rob Bodington [mailto:rob.bodington@eurostep.com] >>> *Sent:* den 23 september 2005 09:57 >>> *To:* plcs-dex@lists.oasis-open.org >>> *Subject:* [plcs-dex] Issue: Use of /IGNORE >>> >>> Hi >>> >>> A core of plcs modellers met this week. >>> >>> We raised and addressed this issue. >>> >>> If anyone does not like the resolution please say so. >>> >>> >>> >>> >>> >>> */Issue: RBN-1 by Rob Bodington (/**/05-09-02/**/)/*/ >>> minor_technical issue / >>> /Resolution: Accept. Status: open/ >>> >>> /IGNORE is used inconsistently throughout the capabilities. >>> >>> According to AP239 annex and > > dexlib/help/dex/implementor_trans.xml, > >>> the following should be used. >>> >>> In particular optional values should default to '$' and only be > > set > >>> to '/IGNORE' if there is a value assigned. >>> >>> *Value* >>> >>> >>> >>> *Description* >>> >>> '' >>> >>> >>> >>> indicates user data managed by the sending system but not > > provided > >>> for data exchange. >>> >>> '/NULL' >>> >>> >>> >>> indicates user data in a mandatory attribute that is not managed > > by > >>> the sending system or currently not known. >>> >>> '$' >>> >>> >>> >>> $ is used in the physical file, if an optional attribute is not >>> instantiated. >>> >>> '/IGNORE' >>> >>> >>> >>> Attribute values are set to '/IGNORE' when the information that >>> could be held by the attribute is instead assigned to the > > instance > >>> of the entity. >>> >>> *Table — Attribute values* >>> >>> *Comment: *(Rob Bodington 05-09-21*)* >>> The proposal is that wherever an attribute should not be used, > > i.e. > >>> it should have been removed from the model as assignment is used >>> instead, it should be populated with /IGNORE, regardless of > > whether > >>> the attribute is used or not. This means that any translator does >>> not have to parse the attributes to determine whether there is an >>> assignment holding the value or not. This should be consistent >>> through out. >>> >>> >>> >>> >>> >>> Regards >>> Rob >>> >>> ------------------------------------------- >>> Rob Bodington >>> Eurostep Limited >>> Web Page: http://www.eurostep.com > > <http://www.eurostep.com/> > >>> http://www.share-a-space.com > > <http://www.share-a-space.com/> > >>> Email: Rob.Bodington@eurostep.com >>> Phone: +44 (0)1454 270030 >>> Mobile: +44 (0)7796 176 401 >>> >>> >>> >> >> >>-- >>==Per-Åke Ling email: per-ake.ling_AT_eurostep.com .~. >>Eurostep AB mobile: +46 709 566 490 / v >>Vasagatan 38 http://www.eurostep.com /( _ ) >>SE-111 20 Stockholm ^ ^ >> >> >> >> >> >> > > > ________________________________________________ > Message sent using UebiMiau 2.7.2 > -- ======================================================== Per-Åke Ling email: per-ake.ling_AT_eurostep.com .~. Eurostep AB mobile: +46 709 566 490 / v \ Vasagatan 38 http://www.eurostep.com /( _ )\ SE-111 20 Stockholm ^ ^
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