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Re: [ddlm-group] Revisiting list delimiters. .. .
- To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
- Subject: Re: [ddlm-group] Revisiting list delimiters. .. .
- From: "Herbert J. Bernstein" <yaya@bernstein-plus-sons.com>
- Date: Thu, 7 Apr 2011 13:59:36 -0400
- In-Reply-To: <8F77913624F7524AACD2A92EAF3BFA54169146B809@11.stjude.org>
- References: <BANLkTimGoJezyeXOq_4uPfOy7n_iP0WHBA@mail.gmail.com><alpine.BSF.2.00.1104060657350.94090@epsilon.pair.com><BANLkTimd-AP5r-iUDKEdw7y5Qo1tKhgEVQ@mail.gmail.com><8F77913624F7524AACD2A92EAF3BFA54169146B806@11.stjude.org><alpine.BSF.2.00.1104071028540.85616@epsilon.pair.com><8F77913624F7524AACD2A92EAF3BFA54169146B809@11.stjude.org>
The only issue to which I think I should respond is whether [,,] conforms to James proposed productions 1. <list> = '[' <whitespace>* {<listdatavalue> {<comma or whitespace><listdatavalue>}*}* ']' 2. <listdatavalue> = {<list>|<string>}<whitespace>* The question would seem to be whether an empty string is a string. While I think such a strong is best presented as '' or "" or . or ? in the whitespace delimited context, I see no issue with a blank delimited empty string in the comma delimited context. However, whether that interpretation survives the discussion or not, I still favor James' proposed productions. Regards, Herbert At 12:31 PM -0500 4/7/11, Bollinger, John C wrote: >On Thursday, April 07, 2011 9:40 AM, Herbert J. Bernstein wrote: > >>Having already done the code for essentially those >>productions in the current release of CBFlib, for me, >>it is less work to adapt to James' productions for CIF2 >>than to disable the use of commas, so for me accepting >>Nick's lists as valid is easier that making them into >>a syntax error. > > >The productions for using whitespace-only list item separators must >be essentially the same as those for whitespace-only loop item >separators. I infer, therefore, that CBFlib must also already have >productions that can be easily adapted to the current draft spec, or >else that it already chooses a different path anyway. Syntactic >consistency is one of the advantages -- for both people and programs >-- of using the same separators everywhere. > > >>CIF has a long tradition of liberal parsers for reads of >>CIFs, accepting a wide variety of alternate presentations >>of the same information, and writers that produce nice >>neat, human readable versions. I think James' proposal >>is completely consistent with that tradition. > > >Inasmuch as we can postulate programs that perform such >transformations on CIF2 files, and that we can suppose that one of >the things they might do is normalize list separators, James' >proposal is not inconsistent with the tradition you describe. I >don't see that as any kind of justification for the proposal, >however. > > >>Rather than a long repeat of the earlier discussion. I >>would suggest simply voting on James' productions independent >>of the more difficult issue of any additional semantic >>restrictions (e.g. what should be rejected on read as an error >>even though it conforms to the productions, or what >>should be accepted on read, but not written by a conformant >>writer). If the productions are acceptable, then it is >>worth having the more detailed discussion. If the productions >>are not acceptable, there is no point in discussing the >>rest. > > >I agree that it is not worthwhile to repeat the earlier discussion, >but that is no reason to jump directly to a vote. It seems >reasonable to instead focus on any new information or insights that >did not inform the previous discussion, and then to consider whether >their combination with the considerations already discussed leads >anyone to change their previous opinion. > >So, what is the new information we should consider? James raised >these points: > >JH> the only fully-functional software for processing DDLm domain >dictionaries (Nick, Syd and Ian's demonstration software) expects a >comma separator > >JH> [James's] understanding is that Syd and Nick (now) are strongly >in favour of sticking with comma as the list separator for STAR2 > >JH> other non-CIF domains are already using comma as a list >separator in STAR2 data files. > >JH> for some, a comma may be a useful visual aid for distinguishing >looped items and listed items. > >I responded to each of those points in my first message yesterday: >http://www.iucr.org/__data/iucr/lists/ddlm-group/msg01244.html. The >short form is: (a) the direction of STAR2 is not persuasive (and I >now add that James's proposal still diverges from STAR2), (b) the >demo software will have to be changed anyway, including in this >area, and (c) syntactically distinguishing looped and listed items >has significant drawbacks directly associated with it. > > >>As you can tell, I am in favor of James' productions. > > >Are you? I know you favor allowing both whitespace and comma >separators, but I think you misread James' productions when you >assert (elsewhere) that [,,] would match them. I don't read them >that way, and James previously wrote that it was not his intention >to allow that sort of construct. > >Furthermore, the productions as currently written are flawed at >least because they do not permit tables as list items. They also >yield odd results for where whitespace is allowed relative to commas >(allowed before, but not after). Those issues can be addressed with >relative ease, of course, but they're a good reason to defer voting >on specific productions. > > >Regards, > >John > > >Email Disclaimer: www.stjude.org/emaildisclaimer > >_______________________________________________ >ddlm-group mailing list >ddlm-group@iucr.org >http://scripts.iucr.org/mailman/listinfo/ddlm-group -- ===================================================== 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 ===================================================== _______________________________________________ ddlm-group mailing list ddlm-group@iucr.org http://scripts.iucr.org/mailman/listinfo/ddlm-group
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- References:
- [ddlm-group] Revisiting list delimiters (James Hester)
- Re: [ddlm-group] Revisiting list delimiters (Herbert J. Bernstein)
- Re: [ddlm-group] Revisiting list delimiters (James Hester)
- Re: [ddlm-group] Revisiting list delimiters. . (Bollinger, John C)
- Re: [ddlm-group] Revisiting list delimiters. . (Herbert J. Bernstein)
- Re: [ddlm-group] Revisiting list delimiters. .. . (Bollinger, John C)
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