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Re: [ddlm-group] Simon's elide proposal

On Thursday, January 13, 2011 12:42 PM, Herbert J. Bernstein wrote:
[I wrote:]
>> It should also be noted that Python source code, including its string
>> literals, is restricted to being expressed in the characters of the
>> 7-bit ASCII character set (though they need not necessarily be encoded
>> according to US-ASCII).  Unconditional, bidirectional CIF/Python string
>> compatibility would require that we apply the same restriction to CIF2
>> triple-quoted strings.  I would oppose that.
>That started to change in Python 2.5 which allowed explicit encoding
>declarations, and by Python 3 has vanished even without an
>encoding declaration.  The Python 3 spec is:
>"Python reads program text as Unicode code points; the encoding
>... defaults to UTF8"

Well and good, then.  You previously pointed us to Python 2.7.1 for documentation of the Python semantics proposed for CIF, but Python 3 looks like a better fit.  Python 3 no longer provides the [uU] string prefix, however, so that's different from what Ralf proposed and from what I thought we had been discussing.  That begs the question, *which version of Python* is proposed to provide its string syntax to CIF?

This furthermore demonstrates one of the strategic drawbacks of adopting Python semantics: Python is not static.  We could make CIF semantics well defined by tying them to a specific Python version, perhaps v3.1.3, but does that retain its purported advantages as Python semantics evolve in 3.2, 3.5, 4.0, etc.?  Perhaps it does, but that's not obvious to me.


John C. Bollinger, Ph.D.
Department of Structural Biology
St. Jude Children's Research Hospital

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