[XeTeX] Hyphenation around „ß“

[Philip Taylor]

Jonathan Kew wrote:

> Minimal example, to be run *without* any latex or babel macros:

Slightly modified example to shew the use of Knuth's \showhyphens
macro, with surprising results :

% >>>>> file "de-1996.tex" <<<<<

\catcode`\{=1
\catcode`\}=2
\catcode `\# = 6

\input unicode-letters.tex
\input hyph-de-1996.tex

\font\tenrm = "Times New Roman" at 10pt
\hyphenchar\tenrm=`\-
\tenrm

\hsize=2in
\vsize=8in
\parfillskip=0pt

\def \showhyphens #1{\setbox 0 = \vbox {\parfillskip = 0 pt \hsize =
16383.99999 pt \tenrm \pretolerance = -1 \tolerance = -1 \hbadness = 0
\showboxdepth = 0 \ #1}}
\showhyphens {wußte geißeln}

\noindent wußte geißeln wußte geißeln wußte geißeln
 wußte geißeln wußte geißeln wußte geißeln
 wußte geißeln wußte geißeln wußte geißeln
 wußte geißeln wußte geißeln wußte geißeln
\par

\end

The strangeness :  the output from \showhyphens (modulo
Windows console character set) is :

> Underfull \hbox (badness 10000) in paragraph at lines 19--19
> [] \tenrm wußte geißeln

yet the PDF has hyphenation gei-ßeln & wuß-te.  So how is it
that \showhyphens does not show these hyphenation points, and
(an unrelated question) why does the test example use the
"Reformed orthography" patterns and not the "Traditional
orthography" (1901) ?  Do we not (in theory, at least) need
the traditional orthography patterns in order to hyphenate
words containing eszet ?

** Phil.