[Libreoffice] Approaches to enable international number format import/export in Calc

Surprisingly, Calc doesn't support or even handle import/export from/to Excel international number format, result in lost of information from dates in non-western locale when convert.

For example, these dates in Excel (see i18ndate.xls file)


When import to Calc will become


The reason is that Excel international number format (LCID) is completely different from Calc's.
See https://office.microsoft.com/en-us/excel-help/creating-international-number-formats-HA001034635.aspx

The correct import would generate the following in Calc (see manually-fixed i18ndate.ods)

(note: still see difference in how Excel and Calc interpret Hijri calendar)

See LibO bug
https://bugs.freedesktop.org/show_bug.cgi?id=33089
and the original OOo issue
http://openoffice.org/bugzilla/show_bug.cgi?id=93503

In bugzilla, I and Kohei have made a discussion about the approaches to fix this problem :-
1) When import from Excel, convert Excel LCID (4-8 hex digits) to Calc's natnum and calendar specifier. When export reverse the process to generate the appropriate Excel LCID.
2) When import form Excel, maintain Excel LCID as-is in Calc number format. When export use the LCID already there.

Since this is a feature that effect many non-western locales. Each with specific details in how they handle local calendars and natnums. I think we should make this important decision first, before we start to implement it. This will benefit every non-western locales with natnums and/or local calendars. I know because this is the top-priority bug in Thai, to convert date in buddhist calendar from Excel. Other non-western locales must have faced similar problems.

So what do you think?

--
_/|\_ Samphan Raruenrom.  Osdev - Open Source Development Co., Ltd.
สัมพันธ์ ระรื่นรมย์.  โอเอสเด็บ - บริษัท โอเพนซอร์สดิเวลอปเมนต์ จำกัด
tel: +66 2 269 9889  web: osdev.co.th
twitter: @osdev  facebook: facebook.com/osdev