RE: U+180A Nirugu / U+1807 Sibe Syllable Marker

Richard, Andrew,
Regarding the U+1807 / U+180A then …
We should recommend a change in the ArabicShaping.txt file to be "D" for dual-joining for the U+180A?
We should also recommend that the General Property for both U+1807 as well as U+180A be changed from "Punctuation" to "Letter"?
Greg


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From: Richard Wordingham [mailto:richard.wordingham@ntlworld.com]
Sent: Wednesday, October 28, 2015 9:33 AM
Subject: Re: U+180A Nirugu


A good rendering engine for OpenType will refuse to select a final form for NIRUGU on the basis of it being in final position.  The UCD data file ArabicShaping.txt records it as having the value 'join_causing' for its Joining_Type, which means that characters on either side of it might change shape, but it itself won't.  To get NIRUGU to change shape in final position, its Joining_Type needs to be changed to Dual_Joining.

I fear that renderers may hard-wire this property, rather than getting if from their usual source of Unicode properties.

Richard.
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>From a Unicode perspective anything that is encoded is a "character", so obviously Nirugu and Sibe syllable boundary marker are by definition both characters.  I guess what you mean is that they both act as letters.  However, as both these characters have a Unicode general property of "Po" (Punctuation, other), there may be a problem with treating them as letters, with positional forms and FVS variants
-- I don't know if there is a problem, but am just flagging this as a potential issue to be taken into consideration.

Andrew
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Received on Monday, 9 November 2015 15:58:16 UTC