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Re: [ddlm-group] Result of concatenation operator vote. .. .

Dear John,

   A mistake is still a mistake, no matter how many times it gets repeated.
The requirement to scan one character ahead to terminate a token by
finding whitespace at the lexical level goes back to the first 
implementations of CIF.  That was what was being removed in CIF2.
That removal has consequences.

   Efforts to get clear and unambiguous statments of both STAR
and CIF syntax that are actually consistent with the format of
existing files would be a good idea. but it seems that we never
manage to do that because documenting that reality seems to
always cause somebody concern.  The result is that we have a large
and growing of CIF files that conform to a variety of different
undocumented specs.

   It is a shame.

   Regards,
     Herbert


=====================================================
  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 Thu, 28 Oct 2010, Bollinger, John C wrote:

>
> On Thursday, October 28, 2010 4:48 PM, Herbert J. Bernstein wrote:
>>
>> Let me make this absolutely clear:
>>
>> ;\
>>
>> does not violate the CIF1.1 syntax.  It violates an incorrect
>> description of the CIF1.1 syntax.  This is about as silly as saying
>> the "would that it were the case" violates English syntax because
>> Microsoft word has a grammer checker that does not know about the
>> subjunctive.
>
> I suppose, then, that I am at a loss as to where to find a correct description of the CIF 1.1 syntax.  The spec currently available online at iucr.org agrees with IT vol. G.:
>
> 1) as ITG puts it, "A text field delimited by the <eol>; digraph may not include a semicolon at the start of a line of text as part of its value."  (International Tables vol. G (2005), Section 2.2.7.1.4, numbered paragraph (18).)
>
> 2) The formal grammars presented in both places do not permit a semicolon to appear at the beginning of a line of text inside a text field.  According to them, the first <eol>; digraph following the opening delimiter can only parse as the closing delimiter.
>
> 3) The explanations of both versions of the formal grammar repeat the same restriction on lines inside text fields: "[...] the first character cannot be a semicolon." (ITG 2.2.7.3, numbered paragraph (49))
>
> The specifications available to me are explicit, consistent, repetitive, and clear on this point.  Furthermore, both versions of the specification say
>
> 4) Tokens are separated by whitespace (ITG 2.2.3, third paragraph), and
>
> 5) "For a semicolon-delimited text string, failure to provide trailing white space is an error."  (ITG 2.2.7.3, numbered paragraph (56))
>
>
> Do you have a more authoritative reference than ITG?  Or official errata that alter these provisions?  Or an authoritative supplemental specification that changes them? Where can I find a correct specification?
>
>
> Thanks,
>
> John
> --
> John C. Bollinger, Ph.D.
> Department of Structural Biology
> St. Jude Children's Research Hospital
>
>
>
>
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