Dave Mielke <[EMAIL PROTECTED]> writes: > [quoted lines by Jason White on 2008/11/24 at 18:27 +1100] > >>I agree there is no perfect solution here, particularly for text tables that >>define all 256 possibilities, which I suspect most, perhaps all of them, do. > > Most do simply because it seemed to make sense to do so. There's really no > peractical need, for example, to define the range \x80-\x9F as those usually > are extended control characters which are rarely, if ever, needed.
Well, yes, and no. I still think that the direct correlation between 8bit-bytes and 8dot-cells is a strong argument for a complete mapping. I think the problem we are looking at is a fundamental one which in 6-dot world is usually solved by a proceeding "escape" dot, like the letsign in most contracted braille variants. The point here is really that we are trying to represent something that has no unambigious representation. I think in 6-dot uncontracted text-table world, the question mark approach is OK, because in that world the user assumes every char on the screen consumes one cell. In contracted braille however, the user knows what they read does not correspond to whats on screen in terms of character width. That, and the fact that contracted braille overloads so many symbols allows/requires us to break with the question mark idiom at least for some languages. Two approaches are left IMO, either we break out of 6-dot world in a contraction table and define something with dot7 or dot8 or both so that it is obvious to the user that something special is going on, or we define the unknown character as something like a valid question mark in contracted braille. In german that would be 6-25 I think. In any case, what exactly needs to happen is probably very language dependant and should be under the control of a contraction table author. Dave, in your other post you ask if we should introduce a new opcode "unknown". I think that might be too limited because a contraction table author might want to define begword \uFFFD in a different way as midendword \uFFFD. Its hypothetical, I have no real use for it, but it sounds logical that the context sensitivity could be useful. -- CYa, ⡍⠁⠗⠊⠕ | Debian Developer <URL:http://debian.org/> .''`. | Get my public key via finger mlang/[EMAIL PROTECTED] : :' : | 1024D/7FC1A0854909BCCDBE6C102DDFFC022A6B113E44 `. `' `- <URL:http://delysid.org/> <URL:http://www.staff.tugraz.at/mlang/> _______________________________________________ This message was sent via the BRLTTY mailing list. To post a message, send an e-mail to: [email protected] For general information, go to: http://mielke.cc/mailman/listinfo/brltty
