Re: Latin ligatures and Unicode

From: John Cowan (jcowan@reutershealth.com)
Date: Mon Dec 20 1999 - 15:47:02 EST


Marco.Cimarosti@icl.com wrote:

> Yes, I think it's likely. "f+ZWL+i" would be an explicitly required
> ligature, "f+ZWNL+i" would be an explicitly forbidden ligarure, "f+i" would
> be the programmers' favorite expression: "the default".

Sounds good to me.
 
> I don't understand the cursiveness example that Michael does above; what
> other subtle reasons are there not to unify ZWL with ZWJ?

Primarily that ZWJ and ZWNJ are essentially related to the idea of context-sensitive
letterforms. They function as letters which deceive the shaping process.
In the Arabic context, which is the paradigmatic one for these letters, the
sequence letter+ZWJ deceives the renderer into believing that the letter
is initial rather than isolated. Similarly, in Indic scripts the relevant
forms are "normal", "normal with explicit virama" and "half form", and ZW[N]J
deceives the normal rendering process here as well.

ZWL, though, does not cause "f" to become "the f-form used with i following",
nor "i" to become "the i-form used with f preceding", because there are
no such things, and it would be intolerably ad hoc to make them so.

-- 

Schlingt dreifach einen Kreis vom dies! || John Cowan <jcowan@reutershealth.com> Schliesst euer Aug vor heiliger Schau, || http://www.reutershealth.com Denn er genoss vom Honig-Tau, || http://www.ccil.org/~cowan Und trank die Milch vom Paradies. -- Coleridge (tr. Politzer)



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