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

Dear Herbert,

Thanks for your detailed response. I think I am failing to understand something elementary.  I see nothing in your comments below to indicate why it would be impossible to use the line-folding protocol to split long lines over multiple lines, for arbitrary CIF2 text.  Additionally, I believe your first example below would be a syntax error under both CIF1.1 and CIF2, because the <eol><semicolon> sequence terminates the datavalue regardless of following text.  In other words, I know of nothing in CIF1.1 to indicate that <eol><semicolon> terminates the datavalue only if there is whitespace or <EOF> after the <eol><semicolon>.

If I am incorrect in my thinking, I would appreciate a correction expressed in terms of the formal CIF1.1 grammar.

James.

On Thu, Oct 28, 2010 at 2:27 PM, Herbert J. Bernstein <yaya@bernstein-plus-sons.com> wrote:
Dear James,

 The line folding protocol is in section 26 of

http://www.iucr.org/resources/cif/spec/version1.1/semantics

I tried to get agreement on continuing this use of the backslash and that was firmly and explicitly rejected, effectively removing the entire line folding protocol, which depends on it.  Even if we restore the use of the backslash, there has been a significant change in the termination of a text field.  In CIF 1.1, text field can only end with <eol>; followed either by whitespace or the end of a file, so the existing line folding protocol allows

;\
this is an example of an embedded text field
;\

an embedded text field
;\

;

which is no longer valid under CIF2 because all quoted fields end on the first occurrence of their delimiter, and as stated in the new syntax document, "CIF2 keywords, data block headers, save frame headers, data names, and data values must all be separated from each other by whitespace. Whitespace not otherwise part of a CIF2 syntax element is significant only for this purpose.

Reasoning: The CIF1 specification relies implicitly on the syntactic structure of the language to require whitespace separators between syntax elements. The CIF2 syntax no longer implicitly provides whitespace separators in some cases (notably, after most types
of data values), therefore the requirement is now made explicit."

So under CIF2, the use of the elide to shield the <eol>; is
explcitly an error.

It would be very nice to have the line folding back, either
in the form of the use of the backslash, or by using the
string concatenation operator.


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, James Hester wrote:

I would be happy to indicate the status of the line folding protocol under
the CIF2 draft when introducing the CIF2 draft to COMCIFS.  Perhaps you
could write a few words in reply to this email giving a description of the
status of the line folding protocol under CIF2, as I'm not sure why
line-folding and CIF2 are incompatible.

On Thu, Oct 28, 2010 at 11:09 AM, Herbert J. Bernstein
<yaya@bernstein-plus-sons.com> wrote:
     Dear James,

      I don't mind if the approval of CIF2 has priority if the debate
     on that ends before debate on the concatenation operator, but
     imasmuch as either the concatenation operator or some other
     replacement for the line folding protocol is necessary before
     CIF2 can become a full replacement for CIF1, I would suggest
     that the matter be brought to COMCIFS at the same time
     and we see what happens.

      I would also like to bring the issue of how we transition
     imgCIF before COMCIFS.  That is anther area where CIF2 does
     not yet provide support.

      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, James Hester wrote:

     My count is 2 in favour, 4 against, with Simon (whose vote
     doesn't appear to have come in)
     potentially making that 3 in favour and 4 against.  These
     are not entirely convincing numbers
     for either side. However, although the proponents of the
     concatenation operator are free to
     address COMCIFS on this question, a replay of this vote
     within COMCIFS would lead to at least 3
     opposed and at least one in favour, with Nick's opposition
     making it (at best) a 4-2 vote
     against.  So, I suggest that at this point we delay any
     further consideration of concatenation
     until COMCIFS has approved CIF2.

     In a subsequent email I will therefore put the current
     CIF2 spec to a DDLm group vote, and
     assuming it passes will present it to COMCIFS for final
     approval.
     --
     T +61 (02) 9717 9907
     F +61 (02) 9717 3145
     M +61 (04) 0249 4148


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M +61 (04) 0249 4148


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M +61 (04) 0249 4148
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