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Subject: Re: SV: [plcs-dex] Issue: Use of /IGNORE
All, I meant to separate the behavior expected of a post-processor (i.e. importer or translater) that knew about PLCS and DEXs and where/how data was represented from the behavior of a general purpose EXPRESS parser. The translator, because it knows that Identification_assignment is always used in DEXs, would never even look at Product.Id. Since that's the case, what value is assigned to Product.Id is not really important so why not do the simplest thing you can. Hope that makes sense, David > > 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...) > > > >>&lt;LEIF&gt; Yes ! There is a first draft uploaded to dexlib/docs which > >>shows a suggested &quot;static&quot; usage/non-usage of all entity > > > > attributes.&lt;/LEIF&gt; > > > >> > >>Is this correct? > >> > >>Regards, > >>Per-ÅKe Ling > >> > >>Peter Bergstrom wrote: > >>&gt; Do I understand correctly if this means the following: > >>&gt; > >>&gt; The description attribute on Product is optional. If descriptions are > >>&gt; going to be assigned to entities instead of using the attribute > > > > value, &gt; mainly due to multilingual issues, it then means that all > > > >>&gt; Product.descriptions must be set to '/GNORE' even though they (as > >>&gt; defined now) could just be left out? > >>&gt; > >>&gt; I think this is polluting the physical files, but it is also slightly > >>&gt; more consistent than the current rule, so I will accept it although I > > > > do > > > >>&gt; not really see a need to change the current rule. > >>&gt; > >>&gt; Peter Bergström > >>&gt; > >>&gt; > >>&gt; -----Original Message----- > >>&gt; *From:* Rob Bodington [mailto:rob.bodington@eurostep.com] > >>&gt; *Sent:* den 23 september 2005 09:57 > >>&gt; *To:* plcs-dex@lists.oasis-open.org > >>&gt; *Subject:* [plcs-dex] Issue: Use of /IGNORE > >>&gt; > >>&gt; Hi > >>&gt; > >>&gt; A core of plcs modellers met this week. > >>&gt; > >>&gt; We raised and addressed this issue. > >>&gt; > >>&gt; If anyone does not like the resolution please say so. > >>&gt; > >>&gt; > >>&gt; > >>&gt; > >>&gt; > >>&gt; */Issue: RBN-1 by Rob Bodington (/**/05-09-02/**/)/*/ > >>&gt; minor_technical issue / > >>&gt; /Resolution: Accept. Status: open/ > >>&gt; > >>&gt; /IGNORE is used inconsistently throughout the capabilities. > >>&gt; > >>&gt; According to AP239 annex and > > > > dexlib/help/dex/implementor_trans.xml, > > > >>&gt; the following should be used. > >>&gt; > >>&gt; In particular optional values should default to '$' and only be > > > > set > > > >>&gt; to '/IGNORE' if there is a value assigned. > >>&gt; > >>&gt; *Value* > >>&gt; > >>&gt; > >>&gt; > >>&gt; *Description* > >>&gt; > >>&gt; '' > >>&gt; > >>&gt; > >>&gt; > >>&gt; indicates user data managed by the sending system but not > > > > provided > > > >>&gt; for data exchange. > >>&gt; > >>&gt; '/NULL' > >>&gt; > >>&gt; > >>&gt; > >>&gt; indicates user data in a mandatory attribute that is not managed > > > > by > > > >>&gt; the sending system or currently not known. > >>&gt; > >>&gt; '$' > >>&gt; > >>&gt; > >>&gt; > >>&gt; $ is used in the physical file, if an optional attribute is not > >>&gt; instantiated. > >>&gt; > >>&gt; '/IGNORE' > >>&gt; > >>&gt; > >>&gt; > >>&gt; Attribute values are set to '/IGNORE' when the information that > >>&gt; could be held by the attribute is instead assigned to the > > > > instance > > > >>&gt; of the entity. > >>&gt; > >>&gt; *Table — Attribute values* > >>&gt; > >>&gt; *Comment: *(Rob Bodington 05-09-21*)* > >>&gt; The proposal is that wherever an attribute should not be used, > > > > i.e. > > > >>&gt; it should have been removed from the model as assignment is used > >>&gt; instead, it should be populated with /IGNORE, regardless of > > > > whether > > > >>&gt; the attribute is used or not. This means that any translator does > >>&gt; not have to parse the attributes to determine whether there is an > >>&gt; assignment holding the value or not. This should be consistent > >>&gt; through out. > >>&gt; > >>&gt; > >>&gt; > >>&gt; > >>&gt; > >>&gt; Regards > >>&gt; Rob > >>&gt; > >>&gt; ------------------------------------------- > >>&gt; Rob Bodington > >>&gt; Eurostep Limited > >>&gt; Web Page: http://www.eurostep.com > > > > &lt;http://www.eurostep.com/&gt; > > > >>&gt; http://www.share-a-space.com > > > > &lt;http://www.share-a-space.com/&gt; > > > >>&gt; Email: Rob.Bodington@eurostep.com > >>&gt; Phone: +44 (0)1454 270030 > >>&gt; Mobile: +44 (0)7796 176 401 > >>&gt; > >>&gt; > >>&gt; > >> > >> > >>-- > >>==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 ^ ^ > > > > > > ________________________________________________ Message sent using UebiMiau 2.7.2
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