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% lua-widow-control
% https://github.com/gucci-on-fleek/lua-widow-control
% SPDX-License-Identifier: MPL-2.0+
% SPDX-FileCopyrightText: 2021 Max Chernoff

\NeedsTeXFormat{LaTeX2e}[2015/01/01] % Formats built after 2015 include \LuaTeX{}Base
\ProvidesPackage{lua-widow-control}%
    [2021/11/08 v1.1.0] %%version %%date

\setlength{\clubpenalty}{1}
\setlength{\widowpenalty}{1}
\setlength{\displaywidowpenalty}{0}
\setlength{\interlinepenalty}{0}
\setlength{\brokenpenalty}{0}

% We can't use \\newlength since that makes a \TeX{} "skip", not a "dimen"
\newdimen\lwcemergencystretch
\setlength{\lwcemergencystretch}{3em}

\directlua{require "lua-widow-control"}

% 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. 
\RequirePackage[final]{microtype}

% Define \TeX{} wrappers for Lua functions
\newcommand{\lwcenable}{\directlua{lwc.enable_callbacks()}}
\newcommand{\lwcdisable}{\directlua{lwc.disable_callbacks()}}
\newcommand{\iflwc}{\directlua{lwc.if_lwc_enabled()}}

% Enable \lwc/ by default when the package is loaded.
\lwcenable

% Expansion of some parts of the document, such as section headings, is quite
% undesirable, so we'll disable \lwc/ for certain commands.
\RequirePackage{etoolbox}

\newcommand{\lwc@patch@warning}[1]{\PackageWarning{lua-widow-control}{%
    Patching the \protect#1 command failed%
}}

% We should only reenable \lwc/ at the end if it was already enabled.
\newif\iflwc@should@reenable

\newcommand{\lwc@patch@pre}{\iflwc%
    \lwc@should@reenabletrue%
    \lwcdisable%
\fi}

\newcommand{\lwc@patch@post}{\iflwc@should@reenable%
    \lwcenable%
\fi}

\newcommand{\lwcdisablecmd}[1]{%
    \ifdefined#1
        \pretocmd{#1}{\lwc@patch@pre}{}{\lwc@patch@warning{#1}}%
        \apptocmd{#1}{\lwc@patch@post}{}{\lwc@patch@warning{#1}}%
    \fi
}

\lwcdisablecmd{\@sect} % Sectioning


\endinput