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Re: [ddlm-group] CIF-2 changes

I have no objection to Nick's approach.  I would suggest a straw vote as 
soon as possible, so that we can have move forward on coding.  So to be as 
specific as possible, here is what I think Nick is proposing:

   1.  All the bracketed constructs in a CIF be delimited by {}:
        Lists:  { ..., ... }
        Tuples: { ..., ... }
        Arrays: { ..., ... }
        Tables: { key:value, key:value } with the distinctions among them 
made primarily by the type specifications. Note that the key in a table 
should be a quoted string.

   2.  That array dimensions in a CIF also be delimited by {} as in
{3} or {3,4}

   3.  That the same changes be made in dREL

(Nick, did I get that right?)

I can work with all of the above, and I suspect Nick is right about the
long-term value of consistency here, and reasonably strong typing does
tend to reduce coding errors.  What do other people think?

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 Wed, 28 Oct 2009, Nick Spadaccini wrote:

> The move away from [] lists to {} lists (thus overlapping with {}
> associative arrays) had to do with cleaning up the syntax under CIF-2.
>
> There are legacy issues with existing CIF data names with embedded [] which
> meant that using [ to initiate a list would come unstuck.
>
> Accordingly to simplify matters and to move forward, I proposed using {} to
> define lists or associative arrays. The complication to the parser is that
> you must start to look inside the object to determine which it is.
>
> That is CIF. dREL is a different matter but consistency is a good thing, so
> that it makes sense to keep the syntax the same as a CIF data file. Hence
> your transcription of the dREL code is correct. It makes my work a lot more
> difficult of course because until now I just called up a Python parser to
> handle almost all of dREL.
>
> Such is life.
>
>
> On 25/10/09 10:24 PM, "Herbert J. Bernstein" <yaya@bernstein-plus-sons.com>
> wrote:
>
>> Dear Colleagues,
>>
>>    Please take a look at the dictionaries I have drafted at
>>
>>    http://vcif.sf.net/cif2_dicts
>>
>> and tell me if I am on the right track in trying to convert to CIF-2
>> format dictionaries.  I have taken all the August 2008 () style tuples in
>> the upper level and converted them to October 2009 CIF-2 {} style lists.
>> I have not changed any array dimension specifications, e.g. [*], nor the
>> innards of any methods.
>>
>>    Questions:
>>
>>    1.  Should the dimensions be changed, e.g. from [3] to {3}?
>>    2.  Should there be any changes in dREL methods themselves?
>>
>> For example consider:
>>
>> ======
>> save_function.SymEquiv
>>      _definition.id              'function.SymEquiv'
>>      _definition.update           2007-10-11
>>      _description.text
>> ;
>>       The function
>>                       xyz' =  SymEquiv( symop, symcat, xyz )
>>
>>       returns a fractional coordinate vector xyz' which is input vector
>>       xyz transformed by the input symop 'n_pqr' applied to the symmetry
>>       equivalent matrix extracted from the category symcat.
>> ;
>>      _name.category_id            function
>>      _name.object_id              SymEquiv
>>      _type.purpose                Assigned
>>      _type.container              Array
>>      _type.contents               Real
>>      _type.dimension              [3]
>>       loop_
>>      _method.purpose
>>      _method.expression
>>       Evaluation
>> ;
>>       Function SymEquiv( c :[Single, Symop],    # symop string n_pqr
>>                          l :[Category, Tag],    # loop of symmetry matrices
>>                          x :[Array, Real]    )  # fract coordinate vector
>>       {
>>               s = l [ SymKey( c ) ]
>>
>>               SymEquiv = s.R * x + s.T + SymLat( c )
>>       }
>> ;
>>      save_
>> ======
>>
>> Should that remain the same, or should it be as follows
>>
>> ======
>> save_function.SymEquiv
>>      _definition.id              'function.SymEquiv'
>>      _definition.update           2007-10-11
>>      _description.text
>> ;
>>       The function
>>                       xyz' =  SymEquiv( symop, symcat, xyz )
>>
>>       returns a fractional coordinate vector xyz' which is input vector
>>       xyz transformed by the input symop 'n_pqr' applied to the symmetry
>>       equivalent matrix extracted from the category symcat.
>> ;
>>      _name.category_id            function
>>      _name.object_id              SymEquiv
>>      _type.purpose                Assigned
>>      _type.container              Array
>>      _type.contents               Real
>>      _type.dimension              {3}
>>       loop_
>>      _method.purpose
>>      _method.expression
>>       Evaluation
>> ;
>>       Function SymEquiv( c :{Single, Symop},    # symop string n_pqr
>>                          l :{Category, Tag},    # loop of symmetry matrices
>>                          x :{Array, Real}    )  # fract coordinate vector
>>       {
>>               s = l { SymKey( c ) }
>>
>>               SymEquiv = s.R * x + s.T + SymLat( c )
>>       }
>> ;
>>      save_
>> ======
>>
>> 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
>> =====================================================
>>
>> _______________________________________________
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>> ddlm-group@iucr.org
>> http://scripts.iucr.org/mailman/listinfo/ddlm-group
>
> cheers
>
> Nick
>
> --------------------------------
> Associate Professor N. Spadaccini, PhD
> School of Computer Science & Software Engineering
>
> The University of Western Australia    t: +61 (0)8 6488 3452
> 35 Stirling Highway                    f: +61 (0)8 6488 1089
> CRAWLEY, Perth,  WA  6009 AUSTRALIA   w3: www.csse.uwa.edu.au/~nick
> MBDP  M002
>
> CRICOS Provider Code: 00126G
>
> e: Nick.Spadaccini@uwa.edu.au
>
>
>
>
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