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Re: [ddlm-group] Relationship of CIF2 to legacy platforms

Just as James changes his vote to 2048 :) I suggest we leave it at 2048
bytes, because

(a) it's long enough
(b) we will have at least one thing we WON'T change from the CIF1
specification.

Nick

On 19/11/09 11:19 PM, "Herbert J. Bernstein" <yaya@bernstein-plus-sons.com>
wrote:

> Just to simply the menu of choice, I'll change my vote to 4096.  --
> 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, 19 Nov 2009, David Brown wrote:
> 
>> I have no strong views on line length, but the arrguments for keeping them
>> seem a little stronger than those for abolishing them.  I have no views at
>> all on how long the lines should be other than to note that Acta Cryst.
>> programs get upset if there are more than 80 characters in a line.
>> 
>> David
>> 
>> 
>> 
>> James Hester wrote:
>> 
>> We should resolve the Fortran line length issue as I think we've got
>> enough information on the table - could those who haven't indicated
>> their preference please vote either
>> 
>> (1) CIF2 should have a maximum line length specified or
>> (2) no line length should be specified.
>> 
>> For bonus points, you can indicate what this length should be.
>> 
>> So (including Nick's recent email) I count the votes as:
>> 
>> (1) Herbert (>=2048), Nick (2048), James (4096)
>> (2) Joe
>> 
>> I've added my vote to the fixed line length simply because I accept
>> Herbert's argument that legacy Fortran programs are actually important
>> in the crystallographic world, and a restriction on line length does
>> not impose a burden on CIF readers.  It also imposes a bit of
>> discipline on CIF writers and helps to produce a readable file.
>> 
>> On Fri, Nov 13, 2009 at 3:47 AM, Joe Krahn <krahn@niehs.nih.gov> wrote:
>> 
>> Nick Spadaccini wrote:
>> 
>> On 3/11/09 12:53 AM, "Joe Krahn" <krahn@niehs.nih.gov> wrote:
>> 
>> Herbert,
>> I am only suggesting that maintained Fortran code ought to be able to
>> utilize F2003 STREAM I/O, supported by current versions of GFortran,
>> Intel Fortran and Sun Fortran.
>> 
>> Of course, I probably am not considering all of the issues. STREAM I/O
>> avoids the need for a fixed maximum record length, but even the newest
>> Fortran compilers have very limited UTF-8 support. Even with STREAM I/O,
>> it is not trivial to count trailing blanks as significant.
>> 
>> Maybe the biggest problem is UTF-8. IMHO, it makes sense for UTF-8 to be
>> an optional encoding, rather than just declaring CIF2 is all UTF-8. This
>> 
>> Not sure what you gain by doing this. If it is pure ASCII only then the
>> declaration of UTF-8 inhibits nothing, since ASCII is a subset. If it is not
>> pure ASCII, then it needs to be UTF-8. I can't see how knowing in advance
>> that it is a subset of UTF-8 or possibly the full set of UTF-8 gives you
>> anything.
>> 
>> cheers
>> 
>> Nick
>> 
>> A compiler/language not aware of UTF-8 could avoid errors by rejecting
>> CIF files that contain UTF-8. However, I think the approach being taken
>> is just to allow implementations to restrict usage, rather than put it
>> in the specifications. For example, the plan seems to be that
>> DDL/dictionary definitions will be used to avoid UTF-8 in data names,
>> where it is most likely to be a problem. So, you are right: there is no
>> reason for the CIF2 syntax to make UTF-8 optional when the dictionaries
>> can restrict characters to the ASCII subset.
>> 
>> The other potential legacy issues I know of are fixed maximum line
>> lengths, and significant trailing blanks. Dictionary definitions cannot
>> avoid these. It might be possible to take a similar approach, by
>> avoiding them by implementation conventions rather than making it part
>> of the spec. If these are only going to be an issue for a few more
>> years, it would avoid having to make another syntax change in the near
>> future.
>> 
>> My main interest here is to avoid incompatible implementations. I also
>> think that Fortran, and any other line-oriented I/O software, should be
>> able to do stream-oriented I/O in the near future.
>> 
>> Joe
>> 
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>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
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cheers

Nick

--------------------------------
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