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Re: [ddlm-group] Elide close quotes by doubling?
- To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
- Subject: Re: [ddlm-group] Elide close quotes by doubling?
- From: Nick Spadaccini <nick@csse.uwa.edu.au>
- Date: Wed, 09 Dec 2009 13:54:35 +0800
- Authentication-Results: postfix;
- In-Reply-To: <4B198647.9030901@niehs.nih.gov>
On 5/12/09 5:59 AM, "Joe Krahn" <krahn@niehs.nih.gov> wrote: > OK, I agree that this can be revisited later. If CIF1-embedded quotes > are invalid, then adding a repeat-quote elide will not interfere with > any other syntax, so it does not have to be a concern in the initial > CIF2 spec. Actually it will interfere lexically in CIF2. You are suggesting "" to be the same as an embedded ", however the first subsequent " after the intialising ", terminates the delimited string. Hence "" won't work. But on a wider issue you are simply revisiting the elide discussion of last week(s). There is no great difference between a "" vs \", the reason we couldn't ultimately agree is because of our inability to separate user defined elides and CIF2 generated lexical elides. A CIF2 syntax issue that is not a user issue should be handled by the parser for the user. Others see it as a user issue for them to insert and delete "lexical" elides. James and I see the latter approach as necessarily ambiguous and gave several examples of how it would be ambiguous. >From there we decided that in the end it would be much easier if users used alternative delimiters. > As for Simon's commen on avoiding the need for an elide, maybe he is > including the possibility of containing anything within semicolon quotes > if it is indented by at least one space to elide internal semicolon > quotes. I would rather see a formal elide mechanism, but that is a good > workaround. > > Joe > > > Herbert J. Bernstein wrote: >> Just for the record, we did _not_ agree " that there were enough >> alternative data value delimiters to avoid the use of any eliding >> mechanism,". What we agrees to was to stop arguing about how to >> use a reverse solidus and to take all strings as is. I am certain we >> will eventually need some mechanisms to: >> >> deal with long lines >> deal with quoting of arbitrary text >> >> But neither issue is worth holding up the use of methods as quickly >> as possible. We need to get something out that will allow dictionaries >> to get written using methods and out into use. The current CIF 2 >> specification is adequate to allow dictionaries to get written, and >> to deal with a large subset of what is needed in data files. I hope >> we will continue this discussion _after_ getting CIF 2 with DDLm >> out and in use to see what is appropriate to extend the useful range >> of data files. >> >> ===================================================== >> Herbert J. Bernstein, Professor of Computer Science >> Dowling College, Kramer Science Center, KSC 121 >> Idle Hour Blvd, Oakdale, NY, 11769 >> >> +1-631-244-3035 >> yaya@dowling.edu >> ===================================================== >> >> On Fri, 4 Dec 2009, SIMON WESTRIP wrote: >> >>> Judging by the difficulties we had that eventually led to agreeing >>> that there were enough alternative data value delimiters to avoid >>> the use of any eliding mechanism (and thus returning all values as raw), >>> I suspect that arguing for a different eliding mechanism will also be >>> fruitless? >>> >>> I understand your view (Joe) about CSV, but we have to respect the >>> legacy that is CIF, which is why we have a variety of delimiters. >>> Otherwise, it could probably be argued that only one type of delimiter is >>> necessary >>> (say """")... >>> >>> Cheers >>> alt >>> Simon >>> >>> >>> ____________________________________________________________________________ >>> From: Joe Krahn <krahn@niehs.nih.gov> >>> To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org> >>> Sent: Friday, 4 December, 2009 18:03:03 >>> Subject: [ddlm-group] Elide close quotes by doubling? >>> >>> The reverse solidus (aka backslash) elide was dropped because it really >>> does not work well to elide only the close quote. Now that close quotes >>> are invalid when not followed by white space, it provides the >>> opportunity to elide close quotes by a repeated close-quote sequence, >>> similar to Fortran and CSV format. It is free of most of the >>> repercussions of defining reverse-solidus as an escape character, and is >>> only making use of a character sequence that would otherwise just be a >>> syntax error. >>> >>> The caveat is that it could misinterpret valid CIF1 values. However, at >>> least RCSB has done a good job of avoiding embedded quotes by picking >>> alternate quoting types. >>> >>> There are workarounds for embedded quotes, even for CIF-within-CIF, so >>> elides are not essential. However, I think this should be easy to >>> implement, and free of the hassles generated by backslash escapes. >>> >>> Thanks, >>> Joe Krahn >>> _______________________________________________ >>> ddlm-group mailing list >>> ddlm-group@iucr.org >>> http://scripts.iucr.org/mailman/listinfo/ddlm-group >>> >>> >> _______________________________________________ >> ddlm-group mailing list >> ddlm-group@iucr.org >> http://scripts.iucr.org/mailman/listinfo/ddlm-group >> > > _______________________________________________ > ddlm-group mailing list > ddlm-group@iucr.org > http://scripts.iucr.org/mailman/listinfo/ddlm-group cheers Nick -------------------------------- Associate Professor N. Spadaccini, PhD School of Computer Science & Software Engineering The University of Western Australia t: +61 (0)8 6488 3452 35 Stirling Highway f: +61 (0)8 6488 1089 CRAWLEY, Perth, WA 6009 AUSTRALIA w3: www.csse.uwa.edu.au/~nick MBDP M002 CRICOS Provider Code: 00126G e: Nick.Spadaccini@uwa.edu.au _______________________________________________ ddlm-group mailing list ddlm-group@iucr.org http://scripts.iucr.org/mailman/listinfo/ddlm-group
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