feat-unicode-nbsp.sil

\begin[papersize=a6]{document}
\neverindent
\nofolios
\language[main=und]
% Reference text
Lorem ipsum dolor sit amet, sit amet adipiscing elit.
Sed non risus. Suspendisse lectus tortor.
\medskip
% Four first spaces are U+00A0.
% Expect proper stretchability as regular spaces.
Lorem ipsum dolor sit amet, consectetur adipiscing elit.\break
Sed non risus. Suspendisse lectus tortor.

% All spaces are U+00A0 but two:
% Expectation:
% Expect non-breakable spaces, shrinking as regular spaces
% when necessary.
Lorem ipsum dolor sit amet, sit amet adipiscing elit.
Sed non risus. Suspendisse lectus tortor.

\set[parameter=linebreak.emergencyStretch, value=20em]
Lorem ipsum dolor sit amet, sit amet adipiscing.
Suspendisse lectus tortor.

% Punctiation spaces are U+00A0 in the following case.
% Expectation:
% French punctuation spaces are managed automatically,
% also replacing U+00A0.
\medskip
\language[main=fr]
Français ? Français : « Français ! »

\end{document}