Should number formats be unique?

[Charlie Clark]

Hi,

I suspect this is too short notice for today's call but we can deal with  
it later. I've recently come across an XLSX file with the following  
section in the styles:

   <numFmts count="3">
     <numFmt numFmtId="164" formatCode="General"/>
     <numFmt numFmtId="165" formatCode="General"/>
     <numFmt numFmtId="166" formatCode="DD\/MM"/>
   </numFmts>

I see a problem here similar to multiply defined CellStyles:

	* multiple instances of the same number format are both confusing and  
redundant
	* this is particularly troubling for the implicit or reserved styles  
because in the GUI "General" will be listed both in the standard  
categories suggesting perhaps different formats.

It seems to me implicit that number formats are unique but there are no  
constraints on this and the narrative documentation is also very vague. I  
think it would help developers if this were clarified even if we stop  
short of a constraint and use phrasing similar to that chosen for  
cellStyles.

Charlie
-- 
Charlie Clark
Managing Director
Clark Consulting & Research
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