\ProvidesPackage{fontsetup}[2024/2/24 v2.1.1 For easily using font families with mathematics]
\RequirePackage{iflang}
\RequirePackage{iftex}
% Provide a test to know if a 16bits TeX is used.
\iftutex
  \RequirePackage{fontspec}
  \RequirePackage{unicode-math}
  \ifxetex
    \@ifpackagewith{fontsetup}{gfsdidotclassic}{\RequirePackage{ucharclasses}}{}
    \@ifpackagewith{fontsetup}{minion}{\RequirePackage{ucharclasses}}{}
    \@ifpackagewith{fontsetup}{msgaramond}{\RequirePackage{ucharclasses}}{}
    \@ifpackagewith{fontsetup}{palatino}{\RequirePackage{ucharclasses}}{}
  \fi
\else
  \PackageError{fontsetup}{Use Unicode-compliant TeX-engines}{%
    The package requires Unicode-compliant engines, e.g.,\MessageBreak
    Xe/LuaLaTeX. Kindly run your code with one of them.%
  }%
\fi
\newif\if@upint
\newif\if@varnothing
\newif\if@newcmbb
\newif\if@erewhon
\newif\if@xcharter
\newif\if@gfs
\newif\if@libertinus
\newif\if@palatino
\newif\if@msgaramond
\newif\if@minion
\newif\if@packagewithoptions
\newcommand*\greeksetup{%
  \newcommand*\leftgrquotes{\char"201C}%
  \newcommand*\rightgrquotes{\char"201E}%
}
\newcommand*\cvfoursetup{%
  \defaultfontfeatures[cv04-Book]{CharacterVariant=4}%
  \defaultfontfeatures[cv04-Regular]{CharacterVariant=4}%
  \defaultfontfeatures[cv04Sans-Book]{CharacterVariant=4}%
  \defaultfontfeatures[cv04Sans-Regular]{CharacterVariant=4}%
  \defaultfontfeatures[cv04Mono-Book]{CharacterVariant=4}%
  \defaultfontfeatures[cv04Sans-Regular]{CharacterVariant=4}%
}
\IfLanguageName{greek}{\greeksetup}{\@ifpackageloaded{xgreek}{\greeksetup}{}}
\newcommand*\ncmsetup{%
  \if@upint
    \if@varnothing
      \if@newcmbb
        \setmathfont[StylisticSet=2,StylisticSet=3,CharacterVariant=1]{NewCMMath-\regularorbook.otf}%
      \else
        \setmathfont[StylisticSet=2,CharacterVariant=1]{NewCMMath-\regularorbook.otf}%
      \fi
    \else
      \if@newcmbb
        \setmathfont[StylisticSet=2,StylisticSet=3]{NewCMMath-\regularorbook.otf}%
      \else
        \setmathfont[StylisticSet=2]{NewCMMath-\regularorbook.otf}%
      \fi
    \fi
  \else
    \if@varnothing
      \if@newcmbb
        \setmathfont[StylisticSet=3,CharacterVariant=1]{NewCMMath-\regularorbook.otf}%
      \else
        \setmathfont[CharacterVariant=1]{NewCMMath-\regularorbook.otf}%
      \fi
    \else
      \if@newcmbb
        \setmathfont[StylisticSet=3]{NewCMMath-\regularorbook.otf}%
      \else
        \setmathfont{NewCMMath-\regularorbook.otf}%
      \fi
    \fi
  \fi
  \IfLanguageName{greek}{\cvfoursetup}{\@ifpackageloaded{xgreek}{\cvfoursetup}{}}}
\DeclareOption{upint}{\@upinttrue}
\DeclareOption{varnothing}{\@varnothingtrue}
\DeclareOption{newcmbb}{\@newcmbbtrue}
\DeclareOption{default}{%
  \input{fspdefault}%
  \begingroup
  \newcommand*{\regularorbook}{Book}%
  \ncmsetup
  \endgroup
  \@packagewithoptionstrue
}
\DeclareOption{olddefault}{%
  \input{fspolddefault}%
  \begingroup
  \newcommand*{\regularorbook}{Regular}%
  \ncmsetup
  \endgroup
  \@packagewithoptionstrue
}
% Install Cambria as a system font.
% cambria.ttc, cambriai.ttf, cambriab.ttf, cambriaz.ttf
\DeclareOption{cambria}{\input{fspcambria}\@packagewithoptionstrue}
\DeclareOption{concrete}{\input{fspconcrete}\@packagewithoptionstrue}
\DeclareOption{ebgaramond}{\input{fspebgaramondot}\@packagewithoptionstrue}
\DeclareOption{erewhon}{\input{fsperewhon}\@erewhontrue\@packagewithoptionstrue}
\DeclareOption{euler}{\input{fspeulerot}\@packagewithoptionstrue}
\DeclareOption{fira}{\input{fspfiraot}\@packagewithoptionstrue}
\DeclareOption{gfsartemisia}{\input{fspgfsartemisiaot}\@packagewithoptionstrue}
\DeclareOption{gfsdidot}{\input{fspgfsdidotot}\@packagewithoptionstrue}
\DeclareOption{gfsdidotclassic}{\input{fspgfsdidotclassicot}\@gfstrue\@packagewithoptionstrue}
\DeclareOption{gfsneohellenic}{\input{fspgfsneohellenicot}\@packagewithoptionstrue}
\DeclareOption{kerkis}{\input{fspkerkisot}\@packagewithoptionstrue}
\DeclareOption{libertinus}{\@libertinustrue\@packagewithoptionstrue}
% Install Lucida in TeX tree
\DeclareOption{lucida}{\input{fsplucidaot}\@packagewithoptionstrue}
% Install MinionPro and provided fspMinionGreekSmallCaps as system fonts.
\DeclareOption{minion}{\input{fspminion}\@miniontrue\@packagewithoptionstrue}
% Install Microsoft Garamond as a system font.
% Gara.ttf, Garai, Garabd
\DeclareOption{msgaramond}{\input{fspmsgaramondot}\@msgaramondtrue\@packagewithoptionstrue}
\DeclareOption{neoeuler}{\input{fspeulerot}\@packagewithoptionstrue}% compatibility
% Not released yet
% \DeclareOption{neokadmus}{\input{neokadmus}}
\DeclareOption{oldstandard}{\input{fspoldstandard}%
  \if@upint
    \setmathfont[StylisticSet=2]{OldStandard-Math.otf}%
  \fi
  \@packagewithoptionstrue
}
% Install Linotype Palatino as a system font.
% pala.ttf palai, palab, palabi.
% Install fspPalatinoGreekSmallCaps as a System font.
\DeclareOption{palatino}{\input{fsppalatinoot}\@palatinotrue\@packagewithoptionstrue}
\DeclareOption{stixtwo}{\input{fspstixtwoot}\@packagewithoptionstrue}
\DeclareOption{talos}{\input{fsptalos}\@packagewithoptionstrue}
\DeclareOption{times}{\input{fsptimesot}\@packagewithoptionstrue}
\DeclareOption{xcharter}{%
  \input{fspxcharter}%
  \@xchartertrue
  \@packagewithoptionstrue
}
\DeclareOption*{\PackageWarning{fontsetup}{Unknown ‘\CurrentOption’}}
\ProcessOptions
\if@packagewithoptions
\else
  \input{fspdefault}%
  \begingroup
  \newcommand*{\regularorbook}{Book}%
  \ncmsetup
  \endgroup
\fi
\AtBeginDocument{%
  \if@erewhon
    \RequirePackage{fourier-otf}
  \fi
  \if@xcharter
    \RequirePackage{xcharter-otf}
     \if@upint
       \setmathfont[StylisticSet=3]{XCharter-Math.otf}%
     \fi
  \fi
  \if@gfs
    \ifxetex
      \PassOptionsToPackage{ucharclasses}{Latin,Greek}
      \setDefaultTransitions{\defaultfont}{}
      \setTransitionsForLatin{\latinfont}{}
      \setTransitionsForGreek{\defaultfont}{}
    \fi
  \fi
  \if@libertinus
    \RequirePackage{libertinus-otf}
  \fi
  \if@palatino
    \PassOptionsToPackage{ucharclasses}{Latin, Greek}
    \setDefaultTransitions{\defaultfont}{}
    \setTransitionsForLatin{\defaultfont}{}
    \setTransitionsForGreek{\greekfont}{}
  \fi
  \if@msgaramond
    \PassOptionsToPackage{ucharclasses}{Latin,Greek}
    \setDefaultTransitions{\defaultfont}{}
    \setTransitionsForLatin{\defaultfont}{}
    \setTransitionsForGreek{\greekfont}{}
  \fi
  \if@minion
    \PassOptionsToPackage{ucharclasses}{Latin,Greek}
    \setDefaultTransitions{\defaultfont}{}
    \setTransitionsForLatin{\defaultfont}{}
    \setTransitionsForGreek{\greekfont}{}
  \fi
}
\endinput