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Re: [ddlm-group] What we have resolved so far

We should split the unresolved issues into separate threads otherwise
we're going to have a hell of a time tracking it all.  To those
reading this message: if I haven't managed to initiate the relevant
threads by the time you feel moved to reply, please do so yourself.

On Thu, Nov 19, 2009 at 12:58 PM, Nick Spadaccini <nick@csse.uwa.edu.au> wrote:
> A quick response to JRH's email, to put things in context. My more detailed
> summary is still coming.
> On 19/11/09 8:22 AM, "James Hester" <jamesrhester@gmail.com> wrote:
>> Nick's forthcoming email notwithstanding, here is a quick list of what
>> I think we have resolved and not resolved so far:
>> 1.  The new standard is called CIF2
>> 2.  All files conforming to the new standard must have a header
>> containing something like the characters "#CIF2"
>> 3.  Non-quote-delimited strings may not contain any
>> syntactically-significant characters (exact character set has been
>> specified by Nick, but before UTF-8 decision)
>> 4.  Quote delimited strings may not contain instances of the
>> terminating character, regardless of following whitespace.
> Unless you do as in (5)
>> 5.  In a quote-delimited string, a reverse solidus escapes the
>> following character, if that character is otherwise syntactically
>> meaningful
>> 6.  Files are UTF-8 encoded
>> 7.  No tuples
>> UNRESOLVED (with notes)
>> 1.  Do we maintain the fixed line length restriction?
>>     - I will post something to the relevant thread to provoke a resolution
> Currently at 2048 bytes. I will propose maintaining this in deference to
> legacy and future Fortran programmes.
>> 2.  Is an escaping reverse solidus part of the datavalue?
>>     - This conversation didn't appear to resolve itself
> I will propose yes, that it is left to a downstream application. This is
> actually consistent with how Python works. My email timestamped
> Mon, 09 Nov 2009 10:35:41 +0800
> Explained my reasoning.
>> 3.  Are square brackets permitted in datanames? (getting close to resolution)
> I will propose a character set restricted with only _ and . as allowed
> punctuation characters. All data names can be identifiers in dREL, and even
> those we assume won't be in dREL can be because someone writing a completely
> different dictionary can import our definitions and then add our data names
> to their dREL scripts.
> To simplify this issue I suggest avoiding the problem. Legacy CIF1 names
> will be aliased in CIF dictionaries so that when we read a CIF1 data name in
> a CIF1 file we can immediately map it to its CIF2 name (this avoids the need
> to remediate all existing CIF1 files).
>> 4.  Does STAR also adopt UTF-8 or go with straight binary? (This may
>> be up to Nick)
> I will propose binary. Any other application domain can then choose UTF-8,
> UTF-16, UCS2 or whatever encoding they wish. This will make Herb's imgCIF a
> legitimate STAR application while not a CIF2 application because of his
> binary component being in binUTF? binUCS?.
>> 5.  Can we use whitespace instead of comma as a list item delimiter?
>>     -not yet tackled seriously but deserves consideration
> I will propose it has to be a comma, but make the coercion rule that space
> separated values in a list-type object be coerced into comma separated
> values. That is, read spaces as you want, but don't encourage them.
>> 6.  Are braces only or square brackets + braces used to delimit lists
>> and associative arrays?
>>     - some consider this decision to be coupled to (3), obvious preference
>>       is for square brackets and braces if other issues are solved
> With my proposal for 3 acceptable, then I would propose returning to [] for
> lists and {} for associative arrays, making it possible to distinguish the
> two at the lexical level by reading the first character.
>> 7.  What is the exact form of the header comment (there was some
>> discussion of adding a second character such as % or !)?
> I think it should be the same as Unix shell headers.
>> 8.  Usage of triple-quoted strings: (a) do we need them? (b) do we
>> need both of them?
> (a) Yes if you want inline multiline strings. (b) Seems superfluous but
> makes encoding a """ in a ''' string much easier (and vice versa) without
> having to elide.
>> 9.  Are general unicode characters allowed in non-quote-delimited strings?
> You know my view on this. I want to discourage non-delimited strings and
> encourage delimited strings. But I can't see (for now) any reason that the
> characters sets have to be different.
> There is one thing about Unicode we have to clarify. The XML specification
> does not allow ALL Unicode characters because some of them (I think) break
> the parsing process. The exclusion set is small, but probably significant. I
> don't know the details but when we say Unicode characters we had better be
> explicit as to which. Herb, you seem to have a handle on the XML spec maybe
> you can explain what the exclusion set is and why. You can propose to this
> group what the Unicode set should be.
> cheers
> Nick
> --------------------------------
> Associate Professor N. Spadaccini, PhD
> School of Computer Science & Software Engineering
> The University of Western Australia    t: +61 (0)8 6488 3452
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