Re: Problem with ConTeXt (MkIV), Hebrew and ligatures

[Simo Ojala <smsojala@gmail.com>]

Hans Hagen <pragma@wxs.nl>

On 09/28/2012 11:46 AM, Hans Hagen wrote:
> On 27-9-2012 21:27, Simo Ojala wrote:
>> This is a problem originally posted in TeX/StackExchange. However, since
>> I have not had any luck in finding a solution I post it here too. I am
>> confident that somebody here should know the answer.
>>
>>
>> http://tex.stackexchange.com/questions/73970/problem-with-context-mkiv-hebrew-and-ligatures
>>
>>
>>
>> "Since I last played with the latest ConTeXt MkIV, there has been
>> introduced this new feature. It now seems to combine Hebrew characters
>> automatically when possible to ligatures. So for example. If I have a
>> word with following two characters:
>>
>> U+05D5 (HEBREW LETTER VAV)
>> U+05BC (HEBREW POINT DAGESH OR MAPIQ)
>>
>> ConTeXt will combine these to:
>>
>> U+FB35 (HEBREW LETTER VAV WITH DAGESH)
>>
>> However, I would need to disable this feature for a number of reasons.
>> For example, this breaks my little database query, because the query key
>> is changed before(?) macro gets it.
>>
>> So if somebody would know how to turn this off and maybe also that what
>> has changed."
>
> It depends on the font ... normally you can disable this by *not* using
> the mark and mkmk features
>
> Hans
>

Ok, I have now tried turning off all kinds of features without luck. So, 
I tried putting together minimal test case. I suspect that there should 
be done something more than just turn off some font features. However, 
my ConTeXt skills are very limited so I can be wrong.

The goal is that the word passed from ConTeXt file remains as it is 
written and gives unicode characters U+5e1, U+5d5, U+5bc and U+5e1. This 
is what already happens when the word is in the lua file.

Simo

PS: In case this matters. My ConTeXt MkIV version is "2012.09.23 12:40". 
It should be the latest for Ubuntu 12.04 LTS Precise Pangolin that is in 
the Adam Reviczky's PPA.


%% testcase.tex

\definefontfeature[hebrew][arabic][script=hebr]
\definefont[dejavusans][name:dejavusans*hebrew at 26pt]
\setupdirections[bidi=global]

\starttext
\dejavusans

\def\Macro#1{\directlua{
dofile(resolvers.findfile("testcase.lua"))
userdata.testfunction("#1")
}}

\Macro{סוּס}

\blank[1cm]however, we can still color these independently\blank[0.5cm]

\color[red]{ס}\color[green]{ו}\color[blue]{ּ}\color[yellow]{ס}

\stoptext


-- testcase.lua

userdata = userdata or {}

function userdata.testfunction(word)
	
	tex.sprint("\\blank[1cm]word passed by macro\\blank[0.5cm]")

	for i = 1, unicode.utf8.len(word) do
		tex.sprint("U+" .. string.format("%x",unicode.utf8.byte(word,i)) .. ": 
" .. unicode.utf8.sub(word,i,i) .. "\\par" )
	end

	tex.sprint("\\blank[1cm]word written in lua file\\blank[0.5cm]")

	word = "סוּס"

	for i = 1, unicode.utf8.len(word) do
		tex.sprint("U+" .. string.format("%x",unicode.utf8.byte(word,i)) .. ": 
" .. unicode.utf8.sub(word,i,i) .. "\\par" )
	end
end

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