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Re: [ddlm-group] Relationship asmong CIF2, STAR, CIF1 and Python. .

I'm frankly not entirely sure why people are exercised about STAR
compatibility.  Perhaps Simon and Herbert could explain why small
syntactical differences are such a big deal?  While I am in favour of
keeping the essential STAR philosophy ("a syntactical container for
data") and maintaining compatibility in abstract datastructures, I
don't see why CIF can't stand on its own legs.  Why is anybody spooked
by the thought that CIF might parse certain vanishingly rare strings
in a different way to STAR?

I note that none of my objections to the Python elide proposal have
anything to do with STAR.

On Fri, Jan 14, 2011 at 11:15 AM, SIMON WESTRIP
<simonwestrip@btinternet.com> wrote:
>> that the CIF2 syntax we had been discussing was a compatible subset of an
>> as-yet unpublished updated version of STAR
>
> This was my assumption.
>
>>I now find that this is not exactly the case...
>
> This is disappointing to say the least.
>
>
>
> ________________________________
> From: "Bollinger, John C" <John.Bollinger@STJUDE.ORG>
> To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
> Sent: Thursday, 13 January, 2011 23:35:21
> Subject: Re: [ddlm-group] Relationship asmong CIF2, STAR, CIF1 and Python. .
>
>
> On Thursday, January 13, 2011 11:18 AM, Herbert J. Bernstein wrote:
>>[...] it has become clear to me that I was
>>making false assumptions about the relationship between
>>CIF2 and STAR.  I believe that a zero-based discussion is
>>now needed on what the relationship should be among CIF2,
>>STAR, CIF1 and Python to best serve the interests
>>of the crystallographic community.  I do not know what
>>is best and do not know how long such a discussion may take.
>>I leave it to James, Nick and Brian to decide if Nick's and
>>Brian's messages should be posted on this list for the record.
>
> Indeed, I find that I, too, was making false assumptions about the
> relationship between CIF2 and STAR.  In particular, I mistakenly believed
> that the CIF2 syntax we had been discussing was a compatible subset of an
> as-yet unpublished updated version of STAR.  I now find that this is not
> exactly the case, at least in that the STAR update now being prepared for
> publication includes a minimal set of string delimiter elides that CIF2 does
> not contain, thus rendering the two incompatible (some well-formed CIF2
> files would not be well-formed STAR files).  As I understand it, these
> elides apply to single-quoted strings and to one form of triple-quoted
> string, using approximately \<delimiter> as the elide.
>
> I'm not entirely sure what would be a "zero-based discussion [...] on what
> the relationship should be among CIF2, STAR, CIF1 and Python to best serve
> the interests of the crystallographic community."  As for what the
> relationship *is*, though, my analysis of CIF1.1 and STAR1, as published in
> ITG, is that all documents conforming to the CIF1.1 syntax also conform to
> the STAR1 syntax, EXCEPT those that contain at least one data block without
> any data in it.  (Empty data blocks are allowed in CIF, but not in STAR1.)
>
> As for what the relationships should be, all we can influence is the
> relationships between CIF2 and the others.  I think they should be something
> like this:
>
> CIF2 <=> CIF1:
> To the greatest extent feasible, well-formed CIF1 documents should be
> well-formed CIF2 documents (modulo a CIF version identification signature)
> having the same meaning.
>
> CIF2 <=> STAR:
> Inasmuch as CIF1 is derived from STAR, I think it appropriate for CIF2 to
> look first to STAR, including its post-CIF1 development, for new features it
> may need.  Even if CIF2 is not 100% compatible with STAR, it is worthwhile
> to avoid diverging without compelling reason.
>
> CIF2 <=> Python:
> I see no particular reason for any formal relationship here beyond Python's
> role as the indirect inspiration for CIF2's new triple-quote syntax.  I am
> wary of the idea of tying CIF tightly to a particular language.  CIF2
> documents are not and never will be Python programs.  I could imagine
> embedding Python in CIF or vise versa, but I have seen no evidence to
> suggest that greater similarity between the two languages' syntax and
> semantics would benefit efforts such as those.
>
>
> Regards,
>
> John
>
> --
> John C. Bollinger, Ph.D.
> Department of Structural Biology
> St. Jude Children's Research Hospital
>
>
> Email Disclaimer:  www.stjude.org/emaildisclaimer
>
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