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Re: [ddlm-group] Removing comma from non-delimited strings
- To: Group finalising DDLm and associated dictionaries <ddlm-group@iucr.org>
- Subject: Re: [ddlm-group] Removing comma from non-delimited strings
- From: James Hester <jamesrhester@gmail.com>
- Date: Fri, 29 Apr 2011 10:38:04 +1000
- In-Reply-To: <11430.48228.qm@web87014.mail.ird.yahoo.com>
- References: <BANLkTim-Hve+-7rtd8BXJ7983Z+PnOCS7A@mail.gmail.com><11430.48228.qm@web87014.mail.ird.yahoo.com>
Hi Simon, You are correct that under the no-comma proposal your first example would become a syntax error, and thus hopefully never appear in a CIF2 file, thus reducing confusion. This is the reasoning behind my point (1). I intend that a comma can never appear in a non-delimited string, not just in the initial position. Some program authors like to write liberal parsers, which upon encountering a syntax error attempt to guess what the author of the file really meant. There is absolutely no requirement to write CIF parsers in this way (and it can be counterproductive) but I have included (2) in the interests of full disclosure. As for your nice final example, that is a question that those wanting to write such robust parsers can argue about (among themselves, not here). As far we need to be concerned it would be a syntax error. On Fri, Apr 29, 2011 at 5:25 AM, SIMON WESTRIP <simonwestrip@btinternet.com> wrote: > If comma is not allowed in non-delimited strings, then > isnt _my_numbers = [1,2,3,4,5,6,7] a syntax error? > > Or do you mean that a comma cannot start a non-delimited string > (in which case 1,2,3,4,5,6,7 is indeed a single value)? > > How does a 'robust CIF2 program' interpret > _names [Mitterrand,Fran\,cois] ? > > Cheers > > Simon > > > > ________________________________ > From: James Hester <jamesrhester@gmail.com> > To: ddlm-group <ddlm-group@iucr.org> > Sent: Thursday, 28 April, 2011 7:49:06 > Subject: [ddlm-group] Removing comma from non-delimited strings > > Dear DDLm group, > > As foreshadowed in the comma-as-list-delimiter discussion, I would > like to suggest adding comma to the list of disallowed characters in > non-delimited text strings, for the following reasons: > > (1) This will improve human readability inside lists if the data value > contains commas, for example: > > _my_numbers = [1,2,3,4,5,6,7] > > is a single-element list although it will appear to be a 7 element > list to all but a CIF2 expert. > > (2) Robust CIF2 programs can interpret commas as list delimiters > without danger of misinterpretation. > -- > 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 > > -- 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
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