[liblouis-liblouisxml] Re: digit vs. litdigit
- From: plundblad@xxxxxxxxxx (Peter Lundblad)
- To: liblouis-liblouisxml@xxxxxxxxxxxxx
- Date: Mon, 3 Dec 2012 15:05:37 -0800
Hi John,
That is the difference between digit and litdigt that I suspected
(although the description of digit in the manual doesn't actually
mention computer braille).
What I am seeing is the following, with the Swedish grade 1 table
(Se-Se-g1.utb)
1. If the table is used as-is, translating:
Test 123.
yields
_test #abc.
and back again yields:
T5st 123.
As you can see, forward translation works fine, but back translation
confuses the dots for the e for a five. That's because there are
digit ...
lines in the table (before the definitions for the latin letters). It seems
like\
the digit lines get used in literary braille (because they cause the nubmer
sign to be
output).
My first attempt to fix this is to replace the digit lines with litdigit.
Translating Test 123. now gives:
_test abc.
Missing number sign, despite litidigts being defined.
Backtranslation is correct:
Test abc.
(For the input).
Doing just a back translation of what would have been the correct output from
forward translation:
_test #abc.
correctly becomes
Test 123.
What works, and what seems to be used for some other tables, is to
replace digits6Dots.uti with digits8Dots.uti and then add
the litdigit opcodes for the six dot digits.
So it seems to me like both digit and litdigit is required to make nubmers
work properly in literary braille, even if the literary braille table
doesn't provide any other computer braille opcodes.
I don't know if that behaviour is intentional.
I could send a patch to fix the Swedish table if you think this fix is
correct. IN addition, as I said in my previous mail, it looks like many other
tables have the same bug, it looks like including include digits6Dots.uti
doesn't have the effect that the authors intended.
I don't know the braille of all those languages, but having conflicting
letters and digits in back translation doesn't seem right to me.
So, should we attempt to fix this globally instead of a one-off for the
Swedish table?
Thanks,
//Peter
John J. Boyer writes:
> The digit and litdigit opcodes are explained in the liblouis
> documentation. digit gives the dot pattern to be used in cimputer
> Braille. litdigit gives the dot pattern to be used in literary Braille.
>
> John
>
>
> On Sun, Dec 02, 2012 at 11:02:38PM +0100, Mesar Hameed
> wrote:
> > Hi John B,
> >
> > I would also be grateful for a clarification on this issue.
> > Unfortunately I personally don't have any time to investigate this anytime
> > soon.
> >
> > Thanks,
> > Mesar
> > On Tue 27/11/12,14:30, Peter Lundblad wrote:
> > > Hi,
> > >
> > > I am looking at some grade 1 tables for back translation (using liblouis
> > > 2.5.1).
> > > I am seeing the problem that digits are confused for the first ten latin
> > > alphabet letters. This happens in a few tables, but let's use
> > > Se-Se-g1.utb as an example.
> > >
> > > Translating e.g.:
> > > Hello 123 hello.
> > > to braille works properly. Backtranslating the result (I use
> > > lou_allround)
> > > gives
> > > 85llo 123 85llo.
> > >
> > > As you can see, the letters a-j get interpreted as
> > > numbers despite not being preceded with a numsign.
> > >
> > > Now, the Swedish table includes digits6Dots.uti with lines
> > > like
> > > digit 0 245
> > > There are no litdigit lines in this table.
> > >
> > > This is obviously not correct, and I actually wonder if most tables
> > > that include digits6Dot and also latinLetterDef6Dots.uti do so
> > > in error, since it causes this conflict.
> > >
> > > Changing to use litdigit fixes backtranslation for letters, but now
> > > there are no numsigns being output on forward translation.
> > > So it seems that we need digit lines to define the characters
> > > as digits and litdigit lines to not confuse digits and letters on
> > > back translations. I see other tables that do this, but then it seems
> > > like we ned to find 10 unused braille patterns to not conflict.
> > > I could get around this by having lines like
> > > noback digit 1 1
> > > litdigit 1 1
> > > ...
> > >
> > > I am not entirely sure about the interaction between digit, litdigit and
> > > other characters. Does anyone have a suggestion for how to
> > > fix backtranslation for Swedish and other tables that have this problem?
> > > (I've tested with the Polish grade 1 table, and, even if I am not familiar
> > > with Polish, it seems pretty obvious that backtranslation is broken
> > > in a similar way there as well.)
> > >
> > > Thanks,
> > > //Peter
> > > For a description of the software, to download it and links to
> > > project pages go to http://www.abilitiessoft.com
> > For a description of the software, to download it and links to
> > project pages go to http://www.abilitiessoft.com
>
> --
> John J. Boyer; President, Chief Software Developer
> Abilitiessoft, Inc.
> http://www.abilitiessoft.com
> Madison, Wisconsin USA
> Developing software for people with disabilities
>
> For a description of the software, to download it and links to
> project pages go to http://www.abilitiessoft.com
For a description of the software, to download it and links to
project pages go to http://www.abilitiessoft.com
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