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Re: [ddlm-group] Space as a list item separator

I am agnostic on this, but note the 'seq' type in DDL1 _type_conditions:

http://www.iucr.org/__data/iucr/cifdic_html/1/ddl_core.dic/Itype_conditions.html

and the consequent appearance of comma-delimited lists in certain STAR
files (specifically MIF, the molecular information file). I know MIF
is little used, though I believe CCDC generate MIF files in some
circumstances.  Anyway, that would tend to nudge me towards preferring
both space and comma in the CIF world.

I guess a corollary of having both is to reinforce the earlier conclusion
that [1,2,,4] (meant to imply some sort of NULL value for a third list
element) is an error.

Brian

On Tue, Dec 01, 2009 at 05:52:48PM +1100, James Hester wrote:
> Dear CIF2 people: the time has come to vote on the list item separator
> issue.  Firstly: as far as I know, nobody is against space as a separator,
> so spaces will be possible list item separators.  Some may be against
> commas, so this vote is on whether or not to allow commas.
> 
> To summarise the arguments:
> 
> 1. In favour of both space and comma
>    - comma is used in some other non-CIF contexts as a list delimiter
> 
> 2. Against comma:
>    - A single type of separator makes the grammar simpler
>    - Space is used everywhere else in CIF as a separator (consistency)
>    - Comma can then be used in non-delimited strings
> 
> Space only: Nick, James (Nick is here)
> Comma and Space: ?
> 
> On Tue, Dec 1, 2009 at 5:30 PM, James Hester <jamesrhester@gmail.com> wrote:
> 
>> More specifically, CIF1.1 excludes square brackets as the first character
>> in a non-delimited string.
>>
>>
>> On Tue, Dec 1, 2009 at 9:33 AM, James Hester <jamesrhester@gmail.com>wrote:
>>
>>> Dear Herbert: as CIF 1.1 doesn't define lists, I'm not sure why you
>>> suggest that the example below is a valid tag.
>>>
>>> On Tue, Dec 1, 2009 at 12:36 AM, Herbert J. Bernstein <
>>> yaya@bernstein-plus-sons.com> wrote:
>>>
>>>> Sorry something got lost in the prior message.  It should have
>>>> read:
>>>>
>>>>  Dear Colleagues,
>>>>>
>>>>>  Back to the question of commas.  If you accept the desirability of
>>>>> having a CIF 1.5, commas in lists become very useful.  Someone with
>>>>> a CIF 1.1 editor will be able to prepare a CIF 1.5 file for many
>>>>> useful cases by doing all lists with commas and no embedded blanks
>>>>> as long as they can make their lists fit on single lines.  In CIF 1.1
>>>>>
>>>>> [[1,2,3],[4,5,6],[7,8,9]]
>>>>>
>>>>> is a valid value for a tag, but
>>>>>
>>>>> [[1 2 3] [4 5 6] [7 8 9]]
>>>>>
>>>>> is not.
>>>>>
>>>>>
>>> No, neither example is a valid CIF 1.1 tag.  CIF 1.1 explicitly excludes
>>> brackets as the first character of a non-delimited string.
>>>
>>>
>>>>> Having the option of commas in lists will help to smooth the
>>>>> transition for at least some people.
> 
> -- 
> T +61 (02) 9717 9907
> F +61 (02) 9717 3145
> M +61 (04) 0249 4148
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