Potentially redundant context rules

[Matitiahu Allouche]

Patrik Fältström asked:
"What about the other way around?
Is there anything that is covered by Tables context rules that is NOT 
covered by the Bidi?"

Sure!  The context rules for ZWJ and ZWNJ, Geresh and Gershayim have no 
equivalent in idnabis-bidi-03.txt.

By the way, even the rules for digits overlap between the 2 documents but 
are far from identical:
- In the Tables document, only Arabic-Indic digits and Extended 
Arabic-Indic digits are mutually exclusive (but can coexist with regular 
digits in the same label).
- In the Bidi document, regular digits (U+0030..U+0039) are mutually 
exclusive with Arabic-Indic digits, while there is no explicit mention of 
Extended Arabic-Indic digits, so by default they will be handled like 
regular digits since they have the same Bidi type (EN).

If we call EN the regular digits, AN the Arabic-Indic digits and XN the 
Extended Arabic-Indic digits, the combinations

- EN and AN is disallowed in Bidi and allowed in the Tables
- EN and XN is allowed in both documents
- AN and XN is disallowed in both documents

Seems to me that some more work is needed here.

Shalom (Regards),  Mati
           Bidi Architect
           Globalization Center Of Competency - Bidirectional Scripts
           IBM Israel
           Phone: +972 2 5888802    Fax: +972 2 5870333    Mobile: +972 52 
2554160