> [Original Message]
> From: L. David Baron <dbaron@dbaron.org>
>
> On Tuesday 2004-03-30 20:53 +0300, Jukka K. Korpela wrote:
> > On Tue, 30 Mar 2004 olafBuddenhagen@web.de wrote:
> > > If Unicode linebreaking rules are any good (I do not know them),
>
> > > the
> > > problem is actually a different one: Nobody but professional
typesetters
> > > do know and respect the five or so different types of dash-like
> > > characters, all fulfilling a different purpose, and all having a
> > > different character code in Unicode (I guess).
>
> > > However, once you actually start to consider the fact that -1
shouldn't
> > > be broken, you'll probably also consider the fact that minus is
> > > something different than a dash or a hyphen...
> > 
> > What makes you think that in "-1", the "-" is inevitably just a
surrogate
> > for minus? Besides, the Unicode standard actually defines "-" as
> > hyphen-minus, as a character with dual (or actually multiple) usage.
> > Yet the Unicode line breaking rules play their own game, forgetting
> > that duality.
>
> The current version [1] of UAX #14 (Line Breaking Properties) doesn't
> forget that duality, as far as I can tell.  The hyphen-minus character
> gets its own character class (HY), and breaks between HY followed by NU
> (numeric character class) are forbidden.

Furthermore, the linebreaking of the hyphen-minus is informative, not
normative in UAX#14.  If an implementation wants  to allow linebreaking
after the HYPHEN-MINUS in  ECMA-262 by default, it may.
There is nothing that prohibits adding a rule like:
   AL HY ÷ NU
between Rules 15 and 18. Indeed, it would probably be a good idea
to add it, since in that context it is probably acting as a HYPHEN
and not a MINUS.