[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Reply to: [list | sender only]
Re: [ddlm-group] Simon's elide proposal
- To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
- Subject: Re: [ddlm-group] Simon's elide proposal
- From: "Herbert J. Bernstein" <yaya@bernstein-plus-sons.com>
- Date: Thu, 13 Jan 2011 16:27:33 -0500 (EST)
- In-Reply-To: <8F77913624F7524AACD2A92EAF3BFA54166D7D1EB3@SJMEMXMBS11.stjude.sjcrh.local>
- References: <AANLkTimdAavg2KCjPZTj1xDYXDQ1JLiQCkQb4snyBErZ@mail.gmail.com><alpine.BSF.2.00.1101120536370.71134@epsilon.pair.com><AANLkTimA8+YXbJ8yS0AtKgFjq9221oMFjR6habn6DsXR@mail.gmail.com><alpine.BSF.2.00.1101120834010.42232@epsilon.pair.com><8F77913624F7524AACD2A92EAF3BFA54166D7D1EA8@SJMEMXMBS11.stjude.sjcrh.local><alpine.BSF.2.00.1101121400400.85750@epsilon.pair.com><alpine.BSF.2.00.1101121556380.31518@epsilon.pair.com><698308.91583.qm@web87015.mail.ird.yahoo.com><alpine.BSF.2.00.1101121845060.90622@epsilon.pair.com><722757.13635.qm@web87012.mail.ird.yahoo.com><8F77913624F7524AACD2A92EAF3BFA54166D7D1EB2@SJMEMXMBS11.stjude.sjcrh.local><alpine.BSF.2.00.1101131319580.27153@epsilon.pair.com><8F77913624F7524AACD2A92EAF3BFA54166D7D1EB3@SJMEMXMBS11.stjude.sjcrh.local>
Dear Colleagues, I do, at present, prefer 2.7 to 3. That seems to be true of most programmers, but at some point we all will face the question of making a transition to 3. 2.7 is not restricted to ASCII characters. 3 is not restricted to ASCII characters. The main point here is that, because 3 has a default encoding of UTF-8, it always allows the restriction to be relaxed, while 2.7, when you don't specify an encoding for the file, defaults to a pure ASCII encoding, and therefore does not allow you to go beyond the ASCII character set. In the earlier decisions we adopted the approach of defaulting to UTF-8 so the restriction would be relaxed. However, for the reasons discussed earlier, I think we need to revisit _all_ the ealier decisions, so I am willing to consider making the default encoding for a CIF2 be pure ASCII, if that is what John B. is proposing. The reason the U and u prefixes are dropped in 3 is precisely because the \u and \U escapes are allowed in all string literals inasmuch as the encoding is UTF-8, and the b prefix was dropped a long time ago, leaving only the r""" and """ versions that Ralf proposed. On the question of the mutability of the Python spec, I agree, it is very, very mutable. I know because I have to teach it to students, and we get burned all the time by the differences among 2.4, 2.6, 2.7 and 3. I am not thrilled about that, so, yes, we need to pick one of them (I prefer 2.7), but, in the spirit of revisting all earier decisions, I would certainly also be willing to consider other possibilities. However, I would hope that whatever is proposed is clean, reasonably stable, well supported code, with source and examples available, much as both Python 2.7 and Python 3 are. The real problem is that the entire computing world is in a major transition, hopefully towards better agreement on something sensible in handling strings of characters. Python seems to be in a reasonable position with respect to the leading edge of that transition, and I suggest we carefully review and consider what they are doing, and make use, where appropriate, of their efforts. I think we will need to try to track somebody, and Python looks like a possibility. ===================================================== 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, 13 Jan 2011, Bollinger, John C wrote: > 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 > > -- > John C. Bollinger, Ph.D. > Department of Structural Biology > St. Jude Children's Research Hospital > > > > > Email Disclaimer: www.stjude.org/emaildisclaimer > > _______________________________________________ > ddlm-group mailing list > ddlm-group@iucr.org > http://scripts.iucr.org/mailman/listinfo/ddlm-group > _______________________________________________ ddlm-group mailing list ddlm-group@iucr.org http://scripts.iucr.org/mailman/listinfo/ddlm-group
Reply to: [list | sender only]
- Follow-Ups:
- Re: [ddlm-group] Simon's elide proposal (Bollinger, John C)
- References:
- [ddlm-group] Simon's elide proposal (James Hester)
- Re: [ddlm-group] Simon's elide proposal (Herbert J. Bernstein)
- Re: [ddlm-group] Simon's elide proposal (James Hester)
- Re: [ddlm-group] Simon's elide proposal (Herbert J. Bernstein)
- Re: [ddlm-group] Simon's elide proposal (Bollinger, John C)
- Re: [ddlm-group] Simon's elide proposal (Herbert J. Bernstein)
- Re: [ddlm-group] Simon's elide proposal (Herbert J. Bernstein)
- Re: [ddlm-group] Simon's elide proposal (SIMON WESTRIP)
- Re: [ddlm-group] Simon's elide proposal (Herbert J. Bernstein)
- Re: [ddlm-group] Simon's elide proposal (SIMON WESTRIP)
- Re: [ddlm-group] Simon's elide proposal (Bollinger, John C)
- Re: [ddlm-group] Simon's elide proposal (Herbert J. Bernstein)
- Re: [ddlm-group] Simon's elide proposal (Bollinger, John C)
- Prev by Date: Re: [ddlm-group] Simon's elide proposal
- Next by Date: Re: [ddlm-group] Simon's elide proposal
- Prev by thread: Re: [ddlm-group] Simon's elide proposal
- Next by thread: Re: [ddlm-group] Simon's elide proposal
- Index(es):