Discussion List Archives

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [ddlm-group] Focusing the elide discussion

Dear James

Sorry for the delay in replying to this request. A long train
journey yesterday gave me the opportunity to review the
discussions on this point. In order of preference I would
rank the proposals as roughly:

F'    - requires least handling of special escapes
E     - allows the generic handling of Unicode character set and
        long lines as native CIF2 features (but only within "special"
        i.e. triple-quote delimited strings)

I think these allow embedding of any string in a reasonably clean way.

C     - I quite like, provided the post-elide escape could be a sequence
        (e.g. borrowing from TeX, the trigraph "{} is read as a
         double-quote; the literal sequence
        <doublequote><open brace><close brace> would be represented by "{}{}
        and any other sequence would have no special meaning). If those with
        greater experience argue that this imposes too great a load on the
        initial lexical scan, or can demonstrate that this leads too
        quickly to a proliferation of unreadable punctuation marks,
        this would drop quickly down the lilst of preferred approaches).
F     - because I'm not sure what is gained just by protecting the
        escape character everywhere; but on the other hand it may seem
        an easy procedure to describe to potential implementors
A
B     - carries an unwelcome overhead in requiring the escape character
        (here, backslash) to be encoded everywhere

D

P     - brings in unnecessary syntactiv overhead when we can achieve a
        closed system by simpler means.

Best wishes
Brian



On Thu, Jan 13, 2011 at 12:20:09AM +1100, James Hester wrote:
> By my count there are 6 distinct proposals for eliding triple-quoted
> strings on the table, which I have listed below.  In order to get an
> idea of where we all stand and which proposals are most likely to
> succeed, I'd like to invite you all to reply to this email with a list
> of proposals which you would find acceptable.  If you like, you can
> rank them in order of preference.  In the list below I've given short
> descriptions, but you should refer to the original emails for the full
> details.  The opinions of COMCIFS voting members are of course most
> significant at this juncture, but I for one am interested in the
> thoughts of the other members as well.
> 
> Proposal P (for Python): Ralf's original proposal to do everything as in Python
> Proposal A: <backslash><delimiter> elides the delimiter, no other
> sequences are significant
> Proposal B: \uxxxx to represent Unicode characters, no other sequences
> are significant
> Proposal C: as yet unspecified character post-elides the delimiter
> where necessary
> Proposal D: as for C, except post-elide character is given immediately
> before opening triple delimiter
> Proposal E: (John B's suggestion) \uxxxx for Unicode character
> together with \<newline> and \\
> Proposal F: (Simon's proposal) \<newline> and \\ only
> Proposal F': (My slight tweak of Simon's proposal) \<newline> only
> when not preceded by \
> 
> I find proposal P unacceptable, and would rank the others in order of
> preference roughly as follows:
> 
> Best: F', F, C
> Bearable: A, B, E
> In a pinch: D
> 
> -- 
> T +61 (02) 9717 9907
> F +61 (02) 9717 3145
> M +61 (04) 0249 4148
> _______________________________________________
> 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]
International Union of Crystallography

Scientific Union Member of the International Science Council (admitted 1947). Member of CODATA, the ISC Committee on Data. Partner with UNESCO, the United Nations Educational, Scientific and Cultural Organization in the International Year of Crystallography 2014.

International Science Council Scientific Freedom Policy

The IUCr observes the basic policy of non-discrimination and affirms the right and freedom of scientists to associate in international scientific activity without regard to such factors as ethnic origin, religion, citizenship, language, political stance, gender, sex or age, in accordance with the Statutes of the International Council for Science.

Useful links