In Brazilian Portuguese, how to get repeat hyphens when hyphenating already hyphenated words with Polyglossia?

Question

In Portuguese, we are supposed to add an hyphen at the beginning of the following line when hyphenation happened where there was already an hyphen. This is quite common because we use hyphens for enclitics (faz-se, for instance) and prefixes (e.g. pós-moderno), this rule was optional and is now coming back as a requirement.

To clarify, if faz-se gets hyphenated, one line will end in faz- and the following one will begin with -se.

All solutions I found call for either reverting back to Babel, or migrating to LuaLaΤεχ, or search and replacing existing hyphens, or some combination thereof. Is there a way to customize Polyglossia, or XəLaΤεχ, to just do the right thing?

Tried:

\documentclass {scrbook}

\usepackage {interchar, polyglossia}

\setlength\textwidth{8cm}

\setmainlanguage {brazil}

\begin {document}

\newintercharclass {\myclass}
\intercharclass {`\-} {\myclass}
\interchartoks {\myclass} {0} {\discretionary {} {-} {}}
\intercharstate {1}

intimidá-la-emos intimidá-la-emos intimidá-la-emos intimidá-la-emos
intimidá-la-emos intimidá-la-emos intimidá-la-emos intimidá-la-emos

\end {document}

Error, presumably because interchar does not like XəΤεχ:

Runaway argument?
! Forbidden control sequence found while scanning use of \cs_generate_variant:N
n.
<inserted text>
            \par
l.31 \cs_generate_variant:Nn \int_to_hexadecimal:n
                                               { V }

interchartoks:

\documentclass {scrbook}

\usepackage {polyglossia}

\setlength\textwidth{8cm}

\setmainlanguage {brazil}

\begin {document}

\XeTeXinterchartokenstate=1
\newXeTeXintercharclass\hyphclass
\newXeTeXintercharclass\letterclass
\XeTeXcharclass`\-=\hyphclass
\newcount\zz
\zz=`\A
\loop
\XeTeXcharclass\zz=\letterclass
\advance\zz 1
\unless\ifnum\zz>`\z
\repeat

\def\zzz-{\discretionary{-}}{-}{-}}

\XeTeXinterchartoks\letterclass\hyphclass{\zzz}

intimidá-la-emos intimidá-la-emos intimidá-la-emos intimidá-la-emos
intimidá-la-emos intimidá-la-emos intimidá-la-emos intimidá-la-emos

\end {document}

Result:

Only the first line break gets the additional hyphen. Presumably because á is not included between A and z. How could I include accented characters in the loop?

Answer 1

This shows one possible approach, using XeTeX character classes to replace a lower case ascii letter followed by a hyphen by a discretionary that repeats the hyphen just a to z are done here but you can add any other letters to the \lettersclass

The same text set with and without the setting.

\documentclass{article}

\setlength\textwidth{8cm}

\begin{document}

abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long
verylongword verylongword verylongword verylongword verylongword 
abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long
verylongword verylongword verylongword verylongword verylongword 
abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long
verylongword verylongword verylongword verylongword verylongword 
abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long
abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long

\XeTeXinterchartokenstate=1
\newXeTeXintercharclass\hyphclass
\newXeTeXintercharclass\letterclass
\XeTeXcharclass`\-=\hyphclass
\newcount\zz
\zz=`\a
\loop
\XeTeXcharclass\zz=\letterclass
\advance\zz 1
\unless\ifnum\zz>`\z
\repeat

\def\zzz-{\discretionary{\textbf{-}}{\textbf{-}}{-}}

\XeTeXinterchartoks\letterclass\hyphclass{\zzz}

abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long
verylongword verylongword verylongword verylongword verylongword 
abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long
verylongword verylongword verylongword verylongword verylongword 
abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long
verylongword verylongword verylongword verylongword verylongword 
abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long
abcd-efg  foo-bar zzz-zz-zz somethinglong some-thing-long

\end{document}