Re: brltty and simultaneous grade 2 translation

[Dave Mielke <dave@mielke.cc>]

[quoted lines by John J. Boyer on November 26, 2001, at 11:39]

>I am assuming that brltty would pass a pointer to a position in a string.

I have a thing against null-terminated strings, and would prefer to pass in an
address and a length.

>The Grade 2 translation routine would then translate until it reached the
>end of the string or until it had enough to fill the Braille display.

Yes, although that'd mean that an additional parameter, i.e. an integer set to
the braille window width, would also need to be passed to the translation
routine.

>If it
>found that the last word would not fit on the display it would backtrack to
>the beginning of that word and just leave a few blanks at the end of the
>display.

That's definitely the simplest, most predictable, and least error prone way to
do it.

>In any case, it would pass back a pointer to the place in the input
>string where translation should resume, or perhaps an integer count of the
>number of characters in the input string that it translated.

I'd prefer an integer count. This count should include any trailing blanks.

>If the pointer into the input string indicating where the translation was to
>begin happened to be in the middle of a word the translator would just
>process the rest of the word, whatever that might turn out to be, instead of
>trying to find the beginning of the word and probably producing some nasty
>bugs.

That's certainly a good starting point. If, with it working that way, there are
no complaints, then it'll prove itself to be an adequate solution.

>I think that cut and paste should simply not be attempted if the Grade 2
>translation is on. Brltty should refuse to carry it out and should display a
>message asking the user to turn grade 2 translation off.

I'd sure like it to work, as I dislike denying functionality based on
implementation restrictions. It could easily be made to work if the translation
routine were to pass back an offset into the input string for each character in
the output buffer.

-- 
Dave Mielke           | 2213 Fox Crescent | I believe that the Bible is the
Phone: 1-613-726-0014 | Ottawa, Ontario   | Word of God. Please contact me
EMail: dave@mielke.cc | Canada  K2A 1H7   | if you're concerned about Hell.