[liblouis-liblouisxml] Re: IPA Braille and Unicode

  • From: Michael Whapples <mwhapples@xxxxxxx>
  • To: liblouis-liblouisxml@xxxxxxxxxxxxx
  • Date: Thu, 09 Jan 2014 23:54:15 +0000

Regarding the question of if liblouis supports 32-bit unicode, the answer is it depends and its out of your control as the table author.


It all depends on how the user's liblouis was compiled. In my mind a mistake to be done that way, but I am not in the mindset of conditional compilation anyway. In my world there should be one build and one build alone (OK, you would need different builds for each platform but the code should be equivalent).

I do not know what would happen if one tried to use a table which needs 32-bit unicode on a 16-bit unicode build.

Also it is worth noting that the 16-bit unicode builds are UCS2 and not UTF16. The latter being a variable width encoding so being capable of representing all characters whereas the former is fixed width and so is limited to the 16-bit character set.

Michael Whapples
On 09/01/2014 15:41, Aaron Cannon wrote:
Hi all.

I've been working on the beginnings of a table to support IPA Braille.
  Has anyone been doing similar?  I would hate to duplicate effort.

Also, doing this has caused me to learn a bit more about Unicode, and
I'm wondering how complete Liblouis's support is for Unicode.  I know
it can handle Unicode codepoints in tables and translation, but I'm
wondering if we are currently doing any normalization?

For those of you not familiar, basically there are multiple ways to
write many unicode characters.  For e with an acute accent, for
example, you can either use the single code point representing e
acute, or you can use an e, followed by a combining acute above
codepoint.  What normalization does is it normalizes all unicode
strings so that every possible character is basically represented in
only one way.

My final question is how many bytes are we using to represent unicode
characters?  Are we supporting 32 bits, or just 16?

Thanks.

Aaron
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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