[luatex] Fribidi for LuaTeX

Idris Samawi Hamid ادريس سماوي حامد ishamid at colostate.edu
Tue Jul 19 20:28:46 CEST 2011

On Tue, 19 Jul 2011 12:06:00 -0600, Khaled Hosny <khaledhosny at eglug.org>  

>> >The algorithm actually has a dedicated rule of this use case:
>> >  http://www.unicode.org/reports/tr9/#Higher-Level_Protocols
>> Sure. At the same time, these are exactly the kinds of rules we
>> _don't_ want to deify.

> I'm not deifying anything, but it is unfair to criticise the algorithm
> for not considering certain use cases while it is actually considering
> them!

>> The people who write these things are not typographers. The bidi
>> algorithm mixes text-editing needs with typesetting needs.

> I haven't seen any evidence of this, no I see how this would be a bad
> thing. Unicode BiDi algorithm have been implemented and deployed by
> millions of users world wide, and its behaviour is what most people
> expect, drifting from it too much is not a wise idea IMO and I can see
> it making more problems than it solves.

A higher-level protocol may use an entirely different algorithm that  
heuristically auto-detects the paragraph embedding level based on the  
paragraph text and its context. For example, it could base it on whether  
there are more RTL characters in the text than LTR. As another example,  
when the paragraph contains no strong characters, its direction could be  
determined by the levels of the paragraphs before and after.

Vague, speculative, and whoever wrote that clearly is not a typographer  
but someone apparently interested in text-editors. For someone writing,  
eg, a multilingual critical edition this would create havoc.

Anyway, the only point was that these rules need not be hard-coded in the  
core of luatex, that's all.

Professor Idris Samawi Hamid, Editor-in-Chief
International Journal of Shīʿī Studies
Department of Philosophy
Colorado State University
Fort Collins, CO 80523

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