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Re: [ddlm-group] Characterset of non-delimited strings insidecompound data items. .. .

Drifting a bit further, I'd question whether the colon is needed in table structures, given that they are delimited uniquely and
must contain <key> <value> pairs, which adhere to the basic delimiting rules in any case... :-)

However, realistically, I'd support restricting the use of []{} from non-delimted strings (assuming I've not missed any major
impact on legacy CIFs by this restriction), or at least ]} (though it might simplify matters to exclude [{ too)

Cheers

Simon


From: "Bollinger, John C" <John.Bollinger@STJUDE.ORG>
To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
Sent: Tuesday, 9 November, 2010 19:08:35
Subject: Re: [ddlm-group] Characterset of non-delimited strings insidecompou nd data items. .. .

We are now drifting a bit , but it would indeed solve the problem if list and table delimiters were required to be separated from other tokens by whitespace.

 

Alternatively, it would also be sufficient to specify that "whitespace-delimited" values must in fact be delimited by whitespace, with a special exception to allow the : in a table key:value to serve as whitespace in that limited context.

 

At this point, however, I would prefer simply restricting ] and }, and perhaps also [ and {, from appearing anywhere in a whitespace-delimited value.  Restricting all of them is equivalent to saying that unquoted [, ], {, and } can serve only in their delimiter roles.  That seems to me a smaller change from what was previously agreed, and also a more intuitive outcome, than the other alternatives provide.

 

 

Regards,

 

John

 

From: ddlm-group-bounces@iucr.org [mailto:ddlm-group-bounces@iucr.org] On Behalf Of SIMON WESTRIP
Sent: Tuesday, November 09, 2010 12:07 PM
To: Group finalising DDLm and associated dictionaries
Subject: Re: [ddlm-group] Characterset of non-delimited strings insidecompou nd data items. .. .

 

If the brackets in these constructs are treated as delimiters (though 'nestable' unlike the other delimiters), then perhaps both the opening and closing delimiter
should be separated from a preceding/subsequent value (or 'parent' value) by whitespace. Afterall, the brackets delimit a *value*, even if that value is made up of other
values? To me this seems quite logical (and actually allows a fairly simple description of the syntax at a lexical level in terms of delimited and non-delimited
'strings' separated by whitespace), but I suspect this will not be received favourably :-)

Cheers

Simon

 

From: "Bollinger, John C" <John.Bollinger@STJUDE.ORG>
To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
Sent: Tuesday, 9 November, 2010 15:35:07
Subject: Re: [ddlm-group] Characterset of non-delimited strings insidecompou nd data items. .

I would be fine with disallowing all of [, ], {, and } from appearing anywhere in a whitespace-delimited data value.  The [ and { do not at present cause lexical ambiguity, but there’s something to be said for consistent treatment of opening and closing delimiters.  Do note, however, that the opening [ of a list or { of a table is still required to be separated from any preceding value by whitespace.  Thus

 

_t            [ depth_1[depth_1_still ] ]

 

would contain an error at the second [.  (There is still an error under the current spec or if only ] and } are forbidden in whitespace-delimited data values, but it is at the final ].)  This is still OK, though:

 

_t            [[depth_2] depth_1]

 

 

John

 


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