On 2/11/15 6:42 PM, Peter Saint-Andre - &yet wrote:
On 2/11/15 6:38 PM, Pete Resnick wrote:
On 2/11/15 6:40 PM, Peter Saint-Andre - &yet wrote:
On 2/11/15 2:33 PM, Pete Resnick wrote:
I think it's good up until the last sentence, which is convoluted. But
the tone is right and we might even want to borrow some text from
Section 3 of RFC 5895. ;-)
A possible refactoring...
OLD
If a profile
really needs to specify a directionality rule, unless a great deal of
careful research into the problems of displaying bidirectional text
is done (which is outside of the scope of this framework), this
document generally recommends using the "Bidi Rule" from [RFC5893]
for profiles based on IdentifierClass, and for profiles based on
FreeformClass or other situations in which IdentifierClass is not
appropriate, that consideration be given to using UAX #9 directly.
NEW
The authors of a profile might think that they need to define a new
directionality rule of their own. This is not a good idea, even if
the authors have done a great deal of careful research into the
problems of displaying bidirectional text. Instead, this document
recommends the following:
o For profiles based on the IdentifierClass, it is best to use the
"Bidi Rule" from the IDNA2008 specification on right-to-left
scripts [RFC5893].
o For profiles based on FreeformClass (or in situations where
IdentifierClass is not appropriate), it is best to follow the
recommendations of Unicode Standard Annex #9 [UAX9] directly.
This misses an essential bit: The original sentence *does not* recommend
using 5893 or UAX9, where your refactoring does. What I presented says,
"*If* you think you need a directionality rule (and you probably don't),
*then* use 5893 or UAX9."
Ah, you want the optative mood. :-)
And even then, it says that if you're basing
on IdentifierClass *and* you really need a directionality rule, we
*generally* recommend 5893. If you're using FreeformClass *and* you
think (for some completely insane reason) that you need a special
directionality rule, you should give *consideration* to UAX9.
If you want to refactor but still capture that, I'm OK.
OK, let me scribble here...
How's this?
The authors of a profile might believe that they need to define a new
directionality rule of their own. Because of the complexity of the
issues involved, such a belief is almost always misguided, even if
the authors have done a great deal of careful research into the
problems of displaying bidirectional strings. This document suggests
that profile authors who are thinking about defining a new
directionality rule think again, and instead consider using the "Bidi
Rule" [RFC5893] (for profiles based on the IdentifierClass) or
following the Unicode bidirectional algorithm [UAX9] directly (for
profiles based on the FreeformClass or in situations where the
IdentifierClass is not appropriate).
One thing that bothers me here is that we're not providing actionable
guidance to the vast majority of non-delusional profile authors. Are we
saying that it's not a good idea to say anything about directionality at
all?
Peter
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