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Re: [ddlm-group] CIF header

Agree to
#<something>CIF_2.0

<something> is whatever character sequence people are happy with.

<something>=\# seems reasonable enough.

Don't see we need for the _ between CIF and 2.0, but agnostic about it. I am
assuming there must be an existing CIF_1.1 magic sequence in use - though I
don't recall any formal specification for it.


On 23/11/09 1:32 PM, "James Hester" <jamesrhester@gmail.com> wrote:

> I agree with Brian's suggestion.  Can other participants also indicate
> their agreement or alternative suggestions?
> 
> James.
> 
> On Fri, Nov 20, 2009 at 11:15 PM, Brian McMahon <bm@iucr.org> wrote:
>>>>> Is there a reason why it can't be #!, to make it consistent with other
>>>>> *nix
>>>>> based directives.
>> 
>> As James says, #! is normally understood by Unix shells to specify
>> an appropriate shell interpreter, not quite what we're aiming for here.
>> 
>> A characteristic initial set of bytes (file 'magic') is often used
>> by GUI file managers and other generic file-handling software to
>> associate icons or applications (in association with, or sometimes
>> competing against, the use of a filename extension). We use this
>> approach to identify the type of file uploaded in our submission
>> system. It's useful for that initial byte sequence to be (a) short
>> to facilitate rapid scanning, (b) specific to an individual file type.
>> For that reason we suggested for CIF 1.1 the magic string
>>      #\#CIF_1.1
>> For CBF it is
>>      ###CBF: VERSION
>> 
>> I recommend #\#CIF_2.0 to be consistent with version 1.1 and so that
>> generic file magic handling can map all #\#CIF_ strings to files of type
>> "cif". (A sophisticated file manager could extend the scan to allow for
>> different icons to be associated with version 1.1 and version 2 CIFs.)
>> It seems a pity from the viewpoint of neatness that the CIF and CBF
>> magic strings aren't more similar in structure.
>> 
>> Brian
>> 
>> On Fri, Nov 20, 2009 at 02:09:56PM +0800, Nick Spadaccini wrote:
>>> 
>>> We don't need an extra character, a single hash would suffice, but I guess
>>> an extra character my uniquely identify it as the CIF header to a parser,
>>> rather than it as just a comment. An extra character also moves you away
>>> from an ordinary comment which is smart, to a smart comment which has its
>>> own unique tag. I am NOT a fan of smart comments, or comments which can be
>>> smart, but they seem to be to modus operandi of many systems.
>>> 
>>> On 20/11/09 1:59 PM, "James Hester" <jamesrhester@gmail.com> wrote:
>>> 
>>>> Wouldn't this cause a UNIX-style OS to try to execute 'CIF2' if
>>>> someone accidentally typed the filename in a command context?  This is
>>>> not a huge problem in that it will otherwise attempt to execute
>>>> 'data_xxxx', and only if the file is executable.
>>>> 
>>>> I guess I don't understand why we need an extra character after the
>>>> hash.  If we really do need an extra character, why not just another
>>>> hash?
>>>> 
>>>> On Mon, Nov 9, 2009 at 7:30 PM, Nick Spadaccini <nick@csse.uwa.edu.au>
>>>> wrote:
>>>>> On 30/10/09 11:47 PM, "Joe Krahn" <krahn@niehs.nih.gov> wrote:
>>>>> 
>>>>>> A directive embedded in an initial comment really does make sense,
>>>>>> because it is irrelevant once the correct parser is selected. It might
>>>>>> make sense to add a specific 2nd character, similar to the POSIX shell
>>>>>> #!. For example, the STAR format could define an initial line beginning
>>>>>> with #% as parsing directive rather than just a plain comment. That
>>>>>> makes the abuse of a comment line as a bit less of a hack.
>>>>> 
>>>>> Is there a reason why it can't be #!, to make it consistent with other
>>>>> *nix
>>>>> based directives.
>>>>> 
>>>>> cheers
>>>>> 
>>>>> Nick
>> _______________________________________________
>> ddlm-group mailing list
>> ddlm-group@iucr.org
>> http://scripts.iucr.org/mailman/listinfo/ddlm-group
>> 
> 
> 

cheers

Nick

--------------------------------
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School of Computer Science & Software Engineering

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