[Dev-luatex] Cron <luatex at boekplan> /var/www/luatex.org/www/bin/luatex-svn

Khaled Hosny khaledhosny at eglug.org
Fri Apr 27 09:59:55 CEST 2012


On Fri, Apr 27, 2012 at 09:28:45AM +0200, Hans Hagen wrote:
> On 27-4-2012 05:26, Khaled Hosny wrote:
> >Hi Taco,
> >
> >With this commit arbitrary number of top and/or bottom accents can be
> >nested and still be positioned properly, so I think there is no need for
> >`\Umathaccent both` anymore, so do you object if we deprecated it now,
> >and later when it is completely removed math accent code can be
> >simplified again (no need for separate field for bottom accents with all
> >its complexity), what do you think?
> >
> >On Thu, Apr 26, 2012 at 10:28:29PM +0200, Cron Daemon wrote:
> >>------------------------------------------------------------------------
> >>r4371 | khaled | 2012-04-26 18:18:10 +0200 (Thu, 26 Apr 2012) | 5 lines
> >>Changed paths:
> >>    M /trunk/source/texk/web2c/luatexdir/tex/mlist.w
> >>
> >>Properly position stacked math accents
> >>
> >>If the accentee is a |sub_math_list|, we check if it is composed of an
> >>|accent_noad| we use the positioning of its nucleus, up to the inner
> >>most |accent_noad|.
> 
> it was introduced with a reason (also proabably inspired by mathml):
> with 'both' we only need to pick up the argument (math expression)
> once

Not sure I understand this.

> can you be a bit more explicit about removing the bottom option? how
> does one position at the bottom then (as Umathbotaccent was
> removed)?

Currently we have:
\Umathaccent <top_accent> <accentee>
\Umathaccent bottom <bottom_accent> <accentee>
\Umathaccent both <top_accent> <accentee> <bottom_accent> <accentee>

The only reason I see for having `both` is to be able to apply top and
bottom accents simultaneously and keep them properly positioned, but
with that commit we can nest any number of accents and they will be
properly positioned, i.e. the same effect can be achieved with:

\Umathaccent <top_accent> {\Umathaccent bottom <bottom_accent> <accentee>}

(the order of accents does not matter), so `both` is redundant and can
be removed and when removed we can simplify the implementation (with no
user visible change). Am I missing anything here?

Regards,
 Khaled


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