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%D \module
%D   [     file=t-lua-widow-control,
%D      version=1.1.0, %%version
%D        title=lua-widow-control,
%D     subtitle=\ConTeXt module for lua-widow-control,
%D       author=Max Chernoff,
%D         date=2021-11-08, %%date
%D    copyright=Max Chernoff,
%D      license=MPL-2.0+,
%D          url=https://github.com/gucci-on-fleek/lua-widow-control]
\startmodule[lua-widow-control]
\unprotect

\installnamespace{lwc}

\installcommandhandler \????lwc {lwc} \????lwc

\newdimen\lwcemergencystretch
\appendtoks
    \lwcemergencystretch=\lwcparameter{emergencystretch}
\to\everysetuplwc

\appendtoks
    \doifelse{\lwcparameter{\c!state}}\v!start{
        \ctxlua{lwc.enable_callbacks()}
    }{
        \ctxlua{lwc.disable_callbacks()}
    }
\to\everysetuplwc

\define\iflwc{\ctxlua{lwc.if_lwc_enabled()}}

\ctxloadluafile{lua-widow-control}

\setuplwc[emergencystretch=3em, \c!state=\v!start]

% We can't just set the penalties because they will be reset automatically
% at \\starttext.
\startsetups[*default]
    \clubpenalty=1
    \widowpenalty=1
    \displaywidowpenalty=0
    \interlinepenalty=0
    \brokenpenalty=0
\stopsetups

\setups[*default]

% Here, we enable font expansion/contraction. It isn't strictly necessary for
% \lwc/'s functionality; however, it is required for the
% lengthened paragraphs to not have terrible spacing. 
\definefontfeature[default][default][expansion=quality]
\setupalign[hz]

% Expansion of some parts of the document, such as section headings, is quite
% undesirable, so we'll disable \lwc/ for certain commands.
% We should only reenable \lwc/ at the end if it was already enabled.
\newif\iflwc@should@reenable

\define\lwc@patch@pre{\iflwc%
    \lwc@should@reenabletrue%
    \setuplwc[state=stop]%
\fi}

\define\lwc@patch@post{\iflwc@should@reenable%
    \setuplwc[state=start]%
\fi}

\prependtoks\lwc@patch@pre\to\everybeforesectionheadhandle % Sectioning
\prependtoks\lwc@patch@post\to\everyaftersectionheadhandle

\protect
\stopmodule