[XeTeX] xunicode questions

[Alan Munn]

At 10:05 PM -0400 6/14/09, David J. Perry wrote:
>Hi all,
>
>As someone with an extensive background in Unicode but relatively 
>new to (Xe)TeX, I have been working to understand exactly what 
>xunicode does.  I cannot find any documentation except the very 
>short readme file on CTAN, and for a non-programmer the source code 
>of xunicode.sty is rough going.  (I'd be happy to help write some 
>docs once I get it figured out!)
>
>I think the following is true, based on tests I have done, but 
>please let me know if it's not:
>
>xunicode takes characters entered through the traditional TeX 
>keystrokes (\'e for e-acute, etc.) and places the precomposed 
>Unicode character (U+00E9 for e-acute) in the output file.  (In 
>other words, it doesn't really matter whether you enter e-acute 
>directly, if you have a keyboard that supports it, or using the TeX 
>keystrokes; you still get the Unicode precomposed character.)   If 
>the combination that you type using traditional TeX methods does not 
>exist in Unicode in precomposed form (e.g., \v y, since y-caron is 
>not a precomposed combination), xunicode inserts the combining mark 
>after the base letter.  I also notice that if I enter 'e' followed 
>by \char"0301, the combining mark remains (i.e., xunicode does not 
>replace this sequence with the precomposed version.)

Yes, this is basically correct.

>
>I have not been able to access IPA characters successfully using the 
>tipa keystrokes.  (I am familiar with tipa.sty, which I assume one 
>would not load in the preamble because one does not want to use the 
>older, non-Unicode IPA fonts; but perhaps that's wrong).  What am I 
>missing?  I think I need to put the keystrokes inside \tipatext{ } 
>but that doesn't work.

This will only work if the font actually contains the IPA glyphs. 
For example, \textipa{@} will produce a schwa if the font is set to 
e.g. Doulos SIL, but will produce a crossed out box if the font is, 
e.g. Adobe Garamond Pro.  Only the former has the correct glyphs.

>
>I can see how to enter circled letters and numbers (not useful to 
>me, but at least I got that part).  There are a large number of 
>other Unicode characters (not combining accents), which seem to be 
>accessed by typing their names (\textwynn, \NG); is that right?

They can be, or they can be entered directly if you have another 
input method (such as a character palette provided by your OS.) For 
example, I have an IPA character palette which allows me to input IPA 
symbols directly into my source. (Of course, I'm so used to tipa 
commands that it's usually faster for me to use that instead...)

>
>Some Unicode characters are in xunicode.sty but are commented out; 
>why? They are as valid as any other Unicode char, AFAIK.
>
>Finally, I noticed that xunicode provides access to some characters 
>in the Private Use Area, specifically the old style numbers.  This 
>surprised me, since XeTeX is one of the few applications that allows 
>users to access alternate number shapes via OpenType or AAT 
>features.  Users therefore have no need to use these PUA values, and 
>using them is not a good practice. (Adobe, for instance, is removing 
>the PUA assignments from oldstyle numerals and small caps as they 
>release new versions of their fonts.)    Perhaps such PUA items 
>should be removed from future versions of xunicode.

Not sure about these two questions. Perhaps Ross can answer them.

Alan

-- 
Alan Munn						amunn at msu.edu
Department of Linguistics
and Germanic, Slavic, Asian and African Languages		Tel. 
	517-355-7491
Michigan State University, East Lansing MI 48824 USA	Fax	517-432-2736