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Re: [ddlm-group] Case sensitivity

Dear Colleagues,

   The issue of case sensitivity of data names is the same as was faced for 
HTML, and I believe we must make the same compromise -- having multiple
flavors of the specification, at the very least:

   1.  A case-insentitive version to avoid breaking existing data sets; and
   2.  A case-sensitive version as the direction for the future


  Herbert J. Bernstein, Professor of Computer Science
    Dowling College, Kramer Science Center, KSC 121
         Idle Hour Blvd, Oakdale, NY, 11769


On Mon, 11 Jan 2010, Joe Krahn wrote:

> If the consensus is lower-case data names, why not make this part of the
> CIF2 standard?
> My suggestion is that every data name should have a "printed form"
> defined in the dictionary. That allows upper-case, spaces, subscripts,
> etc. Then, the item name "I_over_sigmaI" can be written as something
> like "I / sigma(I)". Maybe some already do this?
> With UTF-8 support, names can include non-ASCII characters, such as
> Greek letters. If non-ASCII characters are used, it might be good to
> have a plain ASCII alias rather than assume that UTF-8 is ubiquitous.
> Joe
> David Brown wrote:
>> There was discussion about case sensitivity of data names at the COMCIFS
>> meeting in Osaka.  My recollection is that we agreed that names should
>> be case sensitive, and to avoid problems with having two data names that
>> differ only in their cases, all data names should be lower case.  There
>> are legacy problems because in DDL1 the data names are case insensitive,
>> and while most of the names have been written in lower case, upper case
>> letters have been traditionally used for proper names, e.g.,
>> _space_group_name_Hall.  There may well be legacy CIFs in which only
>> lower case letters have been used but probably not many.
>> DAvid
>> Joe Krahn wrote:
>>> Is there any interest in making CIF2 case-sensitive, at least data names?
>>> There was some discussion that names may eventually extend into the UTF
>>> range, even though it would be avoided for the near future. That
>>> complicates case-insensitive matching, because standard library
>>> functions are locale dependent. If data names are not strictly limited
>>> to 7-bit ASCII, it would be good to make names case-sensitive.
>>> Thanks,
>>> Joe Krahn
>>> _______________________________________________
>>> ddlm-group mailing list
>>> ddlm-group@iucr.org
>>> http://scripts.iucr.org/mailman/listinfo/ddlm-group
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