Re: [ddlm-group] Elide close quotes by doubling?

---

From: Herbert J. Bernstein <yaya@bernstein-plus-sons.com>
To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
Sent: Friday, 4 December, 2009 21:31:58
Subject: Re: [ddlm-group] Elide close quotes by doubling?

Just for the record, we did _not_ agree " that there were enough
alternative data value delimiters to avoid the use of any eliding
mechanism,". What we agrees to was to stop arguing about how to
use a reverse solidus and to take all strings as is.  I am certain we
will eventually need some mechanisms to:

  deal with long lines
  deal with quoting of arbitrary text

But neither issue is worth holding up the use of methods as quickly
as possible.  We need to get something out that will allow dictionaries
to get written using methods and out into use.  The current CIF 2
specification is adequate to allow dictionaries to get written, and
to deal with a large subset of what is needed in data files.  I hope
we will continue this discussion _after_ getting CIF 2 with DDLm
out and in use to see what is appropriate to extend the  useful range
of data files.

=====================================================
  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 Fri, 4 Dec 2009, SIMON WESTRIP wrote:

> Judging by the difficulties we had that eventually led to agreeing
> that there were enough alternative data value delimiters to avoid
> the use of any eliding mechanism (and thus returning all values as raw),
> I suspect that arguing for a different eliding mechanism will also be
> fruitless?
>
> I understand your view (Joe) about CSV, but we have to respect the
> legacy that is CIF, which is why we have a variety of delimiters.
> Otherwise, it could probably be argued that only one type of delimiter is
> necessary
> (say """")...
>
> Cheers
>
> Simon
>
>
> ____________________________________________________________________________
> From: Joe Krahn <krahn@niehs.nih.gov>
> To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
> Sent: Friday, 4 December, 2009 18:03:03
> Subject: [ddlm-group] Elide close quotes by doubling?
>
> The reverse solidus (aka backslash) elide was dropped because it really
> does not work well to elide only the close quote. Now that close quotes
> are invalid when not followed by white space, it provides the
> opportunity to elide close quotes by a repeated close-quote sequence,
> similar to Fortran and CSV format. It is free of most of the
> repercussions of defining reverse-solidus as an escape character, and is
> only making use of a character sequence that would otherwise just be a
> syntax error.
>
> The caveat is that it could misinterpret valid CIF1 values. However, at
> least RCSB has done a good job of avoiding embedded quotes by picking
> alternate quoting types.
>
> There are workarounds for embedded quotes, even for CIF-within-CIF, so
> elides are not essential. However, I think this should be easy to
> implement, and free of the hassles generated by backslash escapes.
>
> Thanks,
> Joe Krahn
> _______________________________________________
> ddlm-group mailing list
> ddlm-group@iucr.org
> http://scripts.iucr.org/mailman/listinfo/ddlm-group
>
>
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