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In order to minimise the number of issues we have to discuss in Madrid to clean up CIF2, I would like to turn discussion to those semantic issues which are relevant to the syntax. I believe that there are three possible types of datavalue: "inapplicable", "unknown" and "string", represented by <full point> (commonly called a "full stop" or "period"), <question mark> and everything else, respectively.
Do we all agree with the following assertion regarding full point and question mark?
(1) A full point/question mark inside string delimiters is *not* equivalent to an undelimited full point/question mark
Numbers: I believe that strings that could be interpreted as numbers are nevertheless (in a formal sense) just strings in the context of the post-parse abstract data model. Therefore, whether or not a numerical string is delimited does not change its value: 4.5 and "4.5" are identical values.
Note that this latter assertion does *not* require that CIF-conformant software must always handle numbers as strings; I am making these statements in order to clarify the abstract data model on which the various DDLs and domain dictionaries operate, not to dictate software design. If your software can manage any potential need to swap between string and number representation of your data value, then more power to you.
Please state whether you agree or disagree with the above.
James.
--
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F +61 (02) 9717 3145
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[ddlm-group] CIF2 semantics
- To: ddlm-group <ddlm-group@iucr.org>
- Subject: [ddlm-group] CIF2 semantics
- From: James Hester <jamesrhester@gmail.com>
- Date: Tue, 26 Jul 2011 13:24:39 +1000
In order to minimise the number of issues we have to discuss in Madrid to clean up CIF2, I would like to turn discussion to those semantic issues which are relevant to the syntax. I believe that there are three possible types of datavalue: "inapplicable", "unknown" and "string", represented by <full point> (commonly called a "full stop" or "period"), <question mark> and everything else, respectively.
Do we all agree with the following assertion regarding full point and question mark?
(1) A full point/question mark inside string delimiters is *not* equivalent to an undelimited full point/question mark
Numbers: I believe that strings that could be interpreted as numbers are nevertheless (in a formal sense) just strings in the context of the post-parse abstract data model. Therefore, whether or not a numerical string is delimited does not change its value: 4.5 and "4.5" are identical values.
Note that this latter assertion does *not* require that CIF-conformant software must always handle numbers as strings; I am making these statements in order to clarify the abstract data model on which the various DDLs and domain dictionaries operate, not to dictate software design. If your software can manage any potential need to swap between string and number representation of your data value, then more power to you.
Please state whether you agree or disagree with the above.
James.
--
T +61 (02) 9717 9907
F +61 (02) 9717 3145
M +61 (04) 0249 4148
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