On 8/2/2016 9:54 PM, Mohammad Hossein Bateni wrote:
Could the problem be because math fonts use mode=base instead of
mode=node? Or is it because in math fonts, the digits and/or full-stop
have different codes?
math fonts are defined and then don't change i.e. they are quite static
and all juggling with individual symbols of sequences is done using
predictable methods
—MHB
On Mon, Aug 1, 2016 at 9:46 AM, Mohammad Hossein Bateni
<bat...@gmail.com <mailto:bat...@gmail.com>> wrote:
Dear list,
I want to add a customized font feature to the math font, to
automatically change the decimal point (unicode 0x2E) to the
Arabic/Farsi version (unicode 0x66B). This will go well with the
mapping from Latin digits to Farsi digits (done in a sample with
mathdigits fallback).
For instance, I want to code in $123.45$ and get a result like
۱۲۳٫۴۵. However, I do not want to simply map 0x2E to 0x66B, because
then "full stop" outside a number will also change. In particular,
I'd like to have the mapping only when full-stop is preceded and
succeeded by a digit. This will, among other things, leave the
end-of-equation periods unchanged.
Here is how I tried to achieve it.
\startluacode
digits = { 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39 }
-- 0x66B instead of 0x2F gives an error!
replacements = { [0x002E] = { 0x2F } }
fonts.handlers.otf.addfeature {
name = "mpf",
type = "chainsubstitution",
lookups = { {
type = "multiple",
data = replacements,
} },
data = {
rules = {
{
current = { { 0x002E } },
after = { digits },
before = { digits },
lookups = { 1 },
}
}
}
}
\stopluacode
\definefontfeature[mathperiod][mpf=yes]
\resetfontfallback [mathdigits]
%\definefontfallback[mathdigits][dejavusansmono][digitsextendedarabicindic][check=yes,force=yes,offset=digitsnormal]
\definefontsynonym
[MathRoman][name:modern][features={math\mathsizesuffix,mathperiod},goodies=lm-math,fallbacks=mathdigits]
\starttext
$123.45.$
123.45.
\addff{mathperiod}
123.45.
\stoptext
Though this font feature works outside math, it does not seem to
have any effect within the math font. Why is that? Can we add font
feature to the math font? Are the character codes different?
Notice that I could not get it to work, so I commented out the
fallback for Persian digits, to make things simpler. To get the
proof of concept, I am trying to change period to forward slash (see
below).
Is the syntax I use for having two features in \defontfontsynonym
correct? Actually, I did try with only mathperiod and it does not
work, either.
When I change 0x2F (slash) to 0x066B in "replacements", I get an
error as follows.
fonts > otf chain > feature 'mpf', type
'gsub_contextchain', chain lookup 'mpf': rule 1 matches at char
U+0002E (period) for (1,1,1) chars, lookuptype 'gsub_multiple'
error:
...ext/tex/texmf-context/tex/context/base/mkiv/font-ots.lua:1232:
attempt to index field '?' (a nil value)
tex error > tex error on line 1 in file
/Users/bateni/farsitex/context/bostan/examples/mathfa/1.tex: ?
\page ->\par
\dosingleempty \page_breaks_process
\strc_pagenumbers_flush_final_page ...\else \page
[\p_strc_pagenumbers_page ...
\dostoptext ...\strc_pagenumbers_flush_final_page
\page \the
\everystoptext ...
l.1 \dostoptext
\clf_stoptext ->\luafunction \16>>clf_stoptext
l.46 \stoptext
Best,
MHB
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