% File: tkz-fn.sty
% Copyright (c) 2026 Alain Matthes
% SPDX-License-Identifier: LPPL-1.3c
% Maintainer: Alain Matthes
%
% tkz-fn : graphs of functions with LuaLaTeX and TikZ.
% Independent of tkz-base and tkz-euclide; optional bridge to tkz-elements.

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{tkz-fn}[2026/10/19 v1.00c Graphs of functions with Lua]
\typeout{Package tkz-fn v1.00c (2026/10/19) loaded.}

\RequirePackage{iftex}
\ifluatex\else
  \PackageError{tkz-fn}{This package requires LuaLaTeX}%
    {Please compile with LuaLaTeX.}%
  \expandafter\endinput
\fi

% ---------------------------------------------------------------------
% options : fr | us (default: fr if babel french is active, else us)
% ---------------------------------------------------------------------
\def\tkzfn@pkgformat{}
\DeclareOption{fr}{\def\tkzfn@pkgformat{fr}}
\DeclareOption{french}{\def\tkzfn@pkgformat{fr}}
\DeclareOption{us}{\def\tkzfn@pkgformat{us}}
\DeclareOption{american}{\def\tkzfn@pkgformat{us}}
\ProcessOptions\relax

\RequirePackage{tikz}
\usetikzlibrary{plotmarks}

\directlua{require("tkz_fn")}
\ifx\tkzfn@pkgformat\@empty\else
  \directlua{tkzfn.set_format("\tkzfn@pkgformat")}
\fi
\AtBeginDocument{%
  \directlua{tkzfn.auto_format("\luaescapestring{\languagename}")}}

% ---------------------------------------------------------------------
% styles
% ---------------------------------------------------------------------
\tikzset{
  tkzfn curve/.style      = {},
  tkzfn tangent/.style    = {},
  tkzfn point/.style      = {draw=black,fill=black},
  tkzfn area/.style       = {fill=lightgray,fill opacity=.5},
  tkzfn riemann/.style    = {draw,fill=gray!20},
  tkzfn line/.style       = {},
  tkzfn grid/.style       = {help lines},
  tkzfn subgrid/.style    = {very thin,opacity=.5},
  tkzfn axis/.style       = {->,>=stealth},
  tkzfn ticks/.style      = {thin},
  tkzfn tick label/.style = {font=\small},
  tkzfn show coord/.style = {dashed,thin},
  tkzfn rep/.style        = {->,>=stealth,very thick},
  tkzfn box/.style        = {},
  tkzfn text/.style       = {},
}

% ---------------------------------------------------------------------
% call of Lua
% The Lua code is built in a group where the active characters of babel
% (: ; ! ? ~) are made harmless, then \directlua is executed outside.
%   \tkzfn@E{...}  : expanded  (numbers, expressions, \foreach variables)
%   \tkzfn@D{...}  : not expanded (TeX text, TikZ options)
%   \tkzfn@DM\macro: contents of a macro, not expanded
% ---------------------------------------------------------------------
\begingroup
  \catcode`\~=13
  \lccode`\~=`\: \lowercase{\endgroup\def\tkzfn@safe@a{\def~{:}}}
\begingroup
  \catcode`\~=13
  \lccode`\~=`\; \lowercase{\endgroup\def\tkzfn@safe@b{\def~{;}}}
\begingroup
  \catcode`\~=13
  \lccode`\~=`\! \lowercase{\endgroup\def\tkzfn@safe@c{\def~{!}}}
\begingroup
  \catcode`\~=13
  \lccode`\~=`\? \lowercase{\endgroup\def\tkzfn@safe@d{\def~{?}}}
\def\tkzfn@safe{%
  \tkzfn@safe@a\tkzfn@safe@b\tkzfn@safe@c\tkzfn@safe@d
  \def~{\string~}}

\def\tkzfn@E#1{\luaescapestring{#1}}
\def\tkzfn@D#1{\luaescapestring{\detokenize{#1}}}
\def\tkzfn@DM#1{\luaescapestring{\detokenize\expandafter{#1}}}

\def\tkzfn@lua#1{%
  \begingroup
    \tkzfn@safe
    \xdef\tkzfn@code{#1}%
  \endgroup
  \directlua{\tkzfn@code}}

% skips spaces before (
\def\tkzfn@sp#1{\@ifnextchar({#1}{\PackageError{tkz-fn}{`(' expected}{}}}

% unknown keys are collected in \tkzfn@tikz and given to TikZ
\def\tkzfn@unknown#1{%
  \def\tkzfn@val{#1}%
  \ifx\tkzfn@val\pgfkeysnovalue@text
    \edef\tkzfn@tikz{\unexpanded\expandafter{\tkzfn@tikz}%
      {\unexpanded\expandafter{\pgfkeyscurrentname}},}%
  \else
    \edef\tkzfn@tikz{\unexpanded\expandafter{\tkzfn@tikz}%
      \unexpanded\expandafter{\pgfkeyscurrentname}={\unexpanded{#1}},}%
  \fi}
% \tkzfn@keys{family}{defaults}{user options}
\def\tkzfn@keys#1#2#3{%
  \def\tkzfn@tikz{}%
  \edef\tkzfn@tmp{\noexpand\pgfqkeys{/tkzfn/#1}%
    {\unexpanded\expandafter{#2},\unexpanded{#3}}}%
  \tkzfn@tmp}
% \tkzfn@family{family}{keys}
\def\tkzfn@family#1#2{%
  \pgfkeys{/tkzfn/#1/.cd,#2,.unknown/.code={\tkzfn@unknown{##1}}}}

% ---------------------------------------------------------------------
% setup
% ---------------------------------------------------------------------
\pgfkeys{/tkzfn/setup/.cd,
  format/.code   = {\directlua{tkzfn.set_format("\luaescapestring{#1}")}},
  decimals/.code = {\directlua{tkzfn.set_decimals("\luaescapestring{#1}")}},
  axes/.code     = {\directlua{tkzfn.set_axes_style("\luaescapestring{#1}")}},
  arrows/.code   = {\directlua{tkzfn.set_arrows("\luaescapestring{#1}")}},
}
\def\tkzFnSetup#1{\pgfqkeys{/tkzfn/setup}{#1}}

% ---------------------------------------------------------------------
% frame : \tkzFnInit[xmin=..,xmax=..,xstep=..,ymin=..,ymax=..,ystep=..]
% ---------------------------------------------------------------------
\pgfkeys{/tkzfn/init/.cd,
  xmin/.store in    = \tkzfn@xmin,
  xmax/.store in    = \tkzfn@xmax,
  xstep/.store in   = \tkzfn@xstep,
  ymin/.store in    = \tkzfn@ymin,
  ymax/.store in    = \tkzfn@ymax,
  ystep/.store in   = \tkzfn@ystep,
  xorigin/.store in = \tkzfn@xorigin,
  yorigin/.store in = \tkzfn@yorigin,
  enlarge/.store in = \tkzfn@enlarge,
  enlarge/.default  = 0.1,
  enlarge x/.store in = \tkzfn@enlargex,
  enlarge y/.store in = \tkzfn@enlargey,
}
\def\tkzFnInit{\@ifnextchar[{\tkzfn@init}{\tkzfn@init[]}}
\def\tkzfn@init[#1]{%
  \begingroup
  \pgfqkeys{/tkzfn/init}{xmin=-5,xmax=5,xstep=1,ymin=-5,ymax=5,ystep=1,
                         xorigin=0,yorigin=0,enlarge=0,enlarge x=,enlarge y=,#1}%
  \tkzfn@lua{tkzfn.init{
    xmin    = "\tkzfn@E\tkzfn@xmin",
    xmax    = "\tkzfn@E\tkzfn@xmax",
    xstep   = "\tkzfn@E\tkzfn@xstep",
    ymin    = "\tkzfn@E\tkzfn@ymin",
    ymax    = "\tkzfn@E\tkzfn@ymax",
    ystep   = "\tkzfn@E\tkzfn@ystep",
    xorigin = "\tkzfn@E\tkzfn@xorigin",
    yorigin = "\tkzfn@E\tkzfn@yorigin",
    enlarge = "\tkzfn@E\tkzfn@enlarge",
    enlargex = "\tkzfn@E\tkzfn@enlargex",
    enlargey = "\tkzfn@E\tkzfn@enlargey"}}%
  \endgroup}

% ---------------------------------------------------------------------
% grid : \tkzFnGrid[dx,dy,sub,subdx,subdy,<TikZ>](x1,y1)(x2,y2)
% ---------------------------------------------------------------------
\tkzfn@family{grid}{
  dx/.store in    = \tkzfn@dx,
  dy/.store in    = \tkzfn@dy,
  sub/.store in   = \tkzfn@sub,
  sub/.default    = true,
  subdx/.store in = \tkzfn@subdx,
  subdy/.store in = \tkzfn@subdy}
\def\tkzFnGrid{\@ifnextchar[{\tkzfn@grid}{\tkzfn@grid[]}}
\def\tkzfn@grid[#1]{%
  \@ifnextchar({\tkzfn@grid@region{#1}}{\tkzfn@grid@do{#1}{}}}
\def\tkzfn@grid@region#1(#2,#3)(#4,#5){\tkzfn@grid@do{#1}{#2,#3,#4,#5}}
\def\tkzfn@grid@do#1#2{%
  \begingroup
  \tkzfn@keys{grid}{dx=,dy=,sub=false,subdx=,subdy=}{#1}%
  \tkzfn@lua{tkzfn.grid{
    dx     = "\tkzfn@E\tkzfn@dx",
    dy     = "\tkzfn@E\tkzfn@dy",
    sub    = "\tkzfn@E\tkzfn@sub",
    subdx  = "\tkzfn@E\tkzfn@subdx",
    subdy  = "\tkzfn@E\tkzfn@subdy",
    region = "\tkzfn@E{#2}",
    opts   = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

% ---------------------------------------------------------------------
% axes
% \tkzFnAxes[dx,dy,xlabel,ylabel,labels,ticks,line,origin,trig,decimals]
% \tkzFnAxisX[label,label style,step,trig,labels,ticks,line,decimals]
% \tkzFnAxisY[label,label style,step,labels,ticks,line,decimals]
% ---------------------------------------------------------------------
\tkzfn@family{axes}{
  dx/.store in       = \tkzfn@dx,
  dy/.store in       = \tkzfn@dy,
  step/.store in     = \tkzfn@step,
  labels/.store in   = \tkzfn@labels,
  ticks/.store in    = \tkzfn@ticks,
  line/.store in     = \tkzfn@line,
  xlabel/.store in   = \tkzfn@xlabel,
  ylabel/.store in   = \tkzfn@ylabel,
  label/.store in    = \tkzfn@label,
  label style/.store in = \tkzfn@labelstyle,
  origin/.store in   = \tkzfn@origin,
  trig/.store in     = \tkzfn@trig,
  decimals/.store in = \tkzfn@decimals,
  box/.store in      = \tkzfn@box,
  box/.default       = true,
  style/.store in    = \tkzfn@axstyle,
  tick length/.store in = \tkzfn@ticklength,
  arrows/.store in   = \tkzfn@arrows}
\def\tkzfn@axes@defaults{dx=,dy=,step=,labels=true,ticks=true,line=true,
  xlabel=,ylabel=,label=,label style=,origin=,trig=0,decimals=4,
  box=false,style=,tick length=,arrows=}
\def\tkzfn@axes@table{%
    dx       = "\tkzfn@E\tkzfn@dx",
    dy       = "\tkzfn@E\tkzfn@dy",
    step     = "\tkzfn@E\tkzfn@step",
    labels   = "\tkzfn@E\tkzfn@labels",
    ticks    = "\tkzfn@E\tkzfn@ticks",
    line     = "\tkzfn@E\tkzfn@line",
    xlabel   = "\tkzfn@DM\tkzfn@xlabel",
    ylabel   = "\tkzfn@DM\tkzfn@ylabel",
    label    = "\tkzfn@DM\tkzfn@label",
    labelstyle = "\tkzfn@DM\tkzfn@labelstyle",
    origin   = "\tkzfn@DM\tkzfn@origin",
    trig     = "\tkzfn@E\tkzfn@trig",
    decimals = "\tkzfn@E\tkzfn@decimals",
    box      = "\tkzfn@E\tkzfn@box",
    style    = "\tkzfn@E\tkzfn@axstyle",
    ticklength = "\tkzfn@E\tkzfn@ticklength",
    arrows   = "\tkzfn@E\tkzfn@arrows",
    opts     = "\tkzfn@DM\tkzfn@tikz"}

\def\tkzFnAxes{\@ifnextchar[{\tkzfn@axes}{\tkzfn@axes[]}}
\def\tkzfn@axes[#1]{%
  \begingroup
  \tkzfn@keys{axes}{\tkzfn@axes@defaults}{#1}%
  \tkzfn@lua{tkzfn.axes{\tkzfn@axes@table}}%
  \endgroup}
\def\tkzFnAxisX{\@ifnextchar[{\tkzfn@axisx}{\tkzfn@axisx[]}}
\def\tkzfn@axisx[#1]{%
  \begingroup
  \tkzfn@keys{axes}{\tkzfn@axes@defaults}{#1}%
  \tkzfn@lua{tkzfn.axis("x",{\tkzfn@axes@table})}%
  \endgroup}
\def\tkzFnAxisY{\@ifnextchar[{\tkzfn@axisy}{\tkzfn@axisy[]}}
\def\tkzfn@axisy[#1]{%
  \begingroup
  \tkzfn@keys{axes}{\tkzfn@axes@defaults}{#1}%
  \tkzfn@lua{tkzfn.axis("y",{\tkzfn@axes@table})}%
  \endgroup}

% clip to the window, frame vectors
\def\tkzFnClip{\@ifnextchar[{\tkzfn@clip}{\tkzfn@clip[0]}}
\def\tkzfn@clip[#1]{\tkzfn@lua{tkzfn.clip{margin = "\tkzfn@E{#1}"}}}

\def\tkzFnRep{\@ifnextchar[{\tkzfn@rep}{\tkzfn@rep[]}}
\def\tkzfn@rep[#1]{\tkzfn@lua{tkzfn.rep{opts = "\tkzfn@D{#1}"}}}

% ---------------------------------------------------------------------
% functions
% \tkzFnDef{f}{x^2-2*x}
% \tkzFnDraw[domain=a:b,samples=n,clip,name,<TikZ>](f)   named function
% \tkzFnDraw[...]{expression}                            expression in x
% ---------------------------------------------------------------------
\def\tkzFnDef#1#2{\tkzfn@lua{tkzfn.def("\tkzfn@E{#1}","\tkzfn@E{#2}")}}

\tkzfn@family{draw}{
  domain/.store in  = \tkzfn@domain,
  samples/.store in = \tkzfn@samples,
  clip/.store in    = \tkzfn@clip,
  clip/.default     = true,
  name/.store in    = \tkzfn@name}
\def\tkzFnDraw{\@ifnextchar[{\tkzfn@draw}{\tkzfn@draw[]}}
\def\tkzfn@draw[#1]{\@ifnextchar({\tkzfn@draw@name{#1}}{\tkzfn@draw@expr{#1}}}
\def\tkzfn@draw@name#1(#2){\tkzfn@dodraw{#1}{name}{#2}}
\def\tkzfn@draw@expr#1#2{\tkzfn@dodraw{#1}{expr}{#2}}
\def\tkzfn@dodraw#1#2#3{%
  \begingroup
  \tkzfn@keys{draw}{domain=,samples=200,clip=true,name=}{#1}%
  \tkzfn@lua{tkzfn.draw_curve{
    kind    = "#2",
    f       = "\tkzfn@E{#3}",
    name    = "\tkzfn@E\tkzfn@name",
    domain  = "\tkzfn@E\tkzfn@domain",
    samples = "\tkzfn@E\tkzfn@samples",
    clip    = "\tkzfn@E\tkzfn@clip",
    opts    = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

% \tkzFnParam[domain,samples,clip,<TikZ>]{x(t)}{y(t)}
\def\tkzFnParam{\@ifnextchar[{\tkzfn@param}{\tkzfn@param[]}}
\def\tkzfn@param[#1]#2#3{%
  \begingroup
  \tkzfn@keys{draw}{domain=,samples=200,clip=false,name=}{#1}%
  \tkzfn@lua{tkzfn.param{
    x       = "\tkzfn@E{#2}",
    y       = "\tkzfn@E{#3}",
    domain  = "\tkzfn@E\tkzfn@domain",
    samples = "\tkzfn@E\tkzfn@samples",
    clip    = "\tkzfn@E\tkzfn@clip",
    opts    = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

% \tkzFnPolar[domain,samples,clip,<TikZ>]{rho(t)}
\def\tkzFnPolar{\@ifnextchar[{\tkzfn@polar}{\tkzfn@polar[]}}
\def\tkzfn@polar[#1]#2{%
  \begingroup
  \tkzfn@keys{draw}{domain=,samples=200,clip=false,name=}{#1}%
  \tkzfn@lua{tkzfn.polar{
    rho     = "\tkzfn@E{#2}",
    domain  = "\tkzfn@E\tkzfn@domain",
    samples = "\tkzfn@E\tkzfn@samples",
    clip    = "\tkzfn@E\tkzfn@clip",
    opts    = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

% ---------------------------------------------------------------------
% points
% \tkzFnDefPoint[draw](f,x){M}     point of the curve of f (z.M with tkz-elements)
% \tkzFnDefPointXY[draw](x,y){M}   point given by its coordinates (frame units)
% \tkzFnDrawPoints[size,<TikZ>](M,N,...)
% \tkzFnMarkPoints[size,<TikZ>](f){list}   points of the curve, no name
% \tkzFnLabelPoint[<TikZ>](M){text}, \tkzFnLabelPoints[<TikZ>](M,N,...)
% \tkzFnShowCoord[xlabel,ylabel,decimals,<TikZ>](M)
% \tkzFnPrintCoord[decimals](M)        coordinates of M, fr or us
% ---------------------------------------------------------------------
\tkzfn@family{points}{
  size/.store in = \tkzfn@size,
  draw/.store in = \tkzfn@drawpt,
  draw/.default  = true}

\def\tkzFnDefPoint{\@ifnextchar[{\tkzfn@defpoint}{\tkzfn@defpoint[]}}
\def\tkzfn@defpoint[#1]{\tkzfn@sp{\tkzfn@defpoint@{#1}}}
\def\tkzfn@defpoint@#1(#2,#3)#4{%
  \begingroup
  \tkzfn@keys{points}{size=1.5pt,draw=false}{#1}%
  \tkzfn@lua{tkzfn.def_point{
    name = "\tkzfn@E{#4}", f = "\tkzfn@E{#2}", x = "\tkzfn@E{#3}",
    draw = "\tkzfn@E\tkzfn@drawpt", size = "\tkzfn@E\tkzfn@size",
    opts = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

\def\tkzFnDefPointXY{\@ifnextchar[{\tkzfn@defpointxy}{\tkzfn@defpointxy[]}}
\def\tkzfn@defpointxy[#1]{\tkzfn@sp{\tkzfn@defpointxy@{#1}}}
\def\tkzfn@defpointxy@#1(#2,#3)#4{%
  \begingroup
  \tkzfn@keys{points}{size=1.5pt,draw=false}{#1}%
  \tkzfn@lua{tkzfn.def_point_xy{
    name = "\tkzfn@E{#4}", x = "\tkzfn@E{#2}", y = "\tkzfn@E{#3}",
    draw = "\tkzfn@E\tkzfn@drawpt", size = "\tkzfn@E\tkzfn@size",
    opts = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

\def\tkzFnDrawPoints{\@ifnextchar[{\tkzfn@drawpoints}{\tkzfn@drawpoints[]}}
\def\tkzfn@drawpoints[#1]{\tkzfn@sp{\tkzfn@drawpoints@{#1}}}
\def\tkzfn@drawpoints@#1(#2){%
  \begingroup
  \tkzfn@keys{points}{size=1.5pt}{#1}%
  \tkzfn@lua{tkzfn.draw_points{list = "\tkzfn@E{#2}",
    size = "\tkzfn@E\tkzfn@size", opts = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}
\let\tkzFnDrawPoint\tkzFnDrawPoints

\def\tkzFnMarkPoints{\@ifnextchar[{\tkzfn@markpoints}{\tkzfn@markpoints[]}}
\def\tkzfn@markpoints[#1]{\tkzfn@sp{\tkzfn@markpoints@{#1}}}
\def\tkzfn@markpoints@#1(#2)#3{%
  \begingroup
  \tkzfn@keys{points}{size=1.5pt}{#1}%
  \tkzfn@lua{tkzfn.mark_points{f = "\tkzfn@E{#2}", list = "\tkzfn@E{#3}",
    size = "\tkzfn@E\tkzfn@size", opts = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

\def\tkzFnLabelPoint{\@ifnextchar[{\tkzfn@labelpoint}{\tkzfn@labelpoint[above right]}}
\def\tkzfn@labelpoint[#1]{\tkzfn@sp{\tkzfn@labelpoint@{#1}}}
\def\tkzfn@labelpoint@#1(#2)#3{\node[#1] at (#2) {#3};}
\def\tkzFnLabelPoints{\@ifnextchar[{\tkzfn@labelpoints}{\tkzfn@labelpoints[above right]}}
\def\tkzfn@labelpoints[#1]{\tkzfn@sp{\tkzfn@labelpoints@{#1}}}
\def\tkzfn@labelpoints@#1(#2){%
  \foreach \tkzfn@p in {#2}{\node[#1] at (\tkzfn@p) {$\tkzfn@p$};}}

\tkzfn@family{showcoord}{
  xlabel/.store in   = \tkzfn@xlabel,
  ylabel/.store in   = \tkzfn@ylabel,
  decimals/.store in = \tkzfn@decimals}
\def\tkzFnShowCoord{\@ifnextchar[{\tkzfn@showcoord}{\tkzfn@showcoord[]}}
\def\tkzfn@showcoord[#1]{\tkzfn@sp{\tkzfn@showcoord@{#1}}}
\def\tkzfn@showcoord@#1(#2){%
  \begingroup
  \tkzfn@keys{showcoord}{xlabel=,ylabel=,decimals=}{#1}%
  \tkzfn@lua{tkzfn.show_coord{name = "\tkzfn@E{#2}",
    xlabel = "\tkzfn@DM\tkzfn@xlabel", ylabel = "\tkzfn@DM\tkzfn@ylabel",
    decimals = "\tkzfn@E\tkzfn@decimals", opts = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

\def\tkzFnPrintCoord{\@ifnextchar[{\tkzfn@printcoord}{\tkzfn@printcoord[]}}
\def\tkzfn@printcoord[#1]{\tkzfn@sp{\tkzfn@printcoord@{#1}}}
\def\tkzfn@printcoord@#1(#2){%
  \tkzfn@lua{tkzfn.print_coord("\tkzfn@E{#2}","\tkzfn@E{#1}")}}

% \tkzFnText[<TikZ>](x,y){text}  or  \tkzFnText[<TikZ>](A){text}
\def\tkzFnText{\@ifnextchar[{\tkzfn@text}{\tkzfn@text[]}}
\def\tkzfn@text[#1]{\tkzfn@sp{\tkzfn@text@{#1}}}
\def\tkzfn@text@#1(#2)#3{%
  \tkzfn@lua{tkzfn.position("\tkzfn@E{#2}")}%
  \edef\tkzfn@tmp{\noexpand\node[tkzfn text,\unexpanded{#1}] at \tkzfnpos}%
  \tkzfn@tmp{#3};}

% ---------------------------------------------------------------------
% tangent : \tkzFnTangent[kl=1,kr=1,draw,clip,<TikZ>](f,x)
% kl, kr : lengths in x units of the frame (0 = no half tangent)
% ---------------------------------------------------------------------
\tkzfn@family{tangent}{
  kl/.store in   = \tkzfn@kl,
  kr/.store in   = \tkzfn@kr,
  draw/.store in = \tkzfn@drawpt,
  draw/.default  = true,
  clip/.store in = \tkzfn@clip,
  clip/.default  = true}
\def\tkzFnTangent{\@ifnextchar[{\tkzfn@tangent}{\tkzfn@tangent[]}}
\def\tkzfn@tangent[#1]{\tkzfn@sp{\tkzfn@tangent@{#1}}}
\def\tkzfn@tangent@#1(#2,#3){%
  \begingroup
  \tkzfn@keys{tangent}{kl=1,kr=1,draw=false,clip=true}{#1}%
  \tkzfn@lua{tkzfn.tangent{
    f    = "\tkzfn@E{#2}",
    x    = "\tkzfn@E{#3}",
    kl   = "\tkzfn@E\tkzfn@kl",
    kr   = "\tkzfn@E\tkzfn@kr",
    draw = "\tkzfn@E\tkzfn@drawpt",
    clip = "\tkzfn@E\tkzfn@clip",
    opts = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

% ---------------------------------------------------------------------
% areas : \tkzFnArea[domain,where,samples,clip,<TikZ>](f)  or  (f,g)
% g : a function name or a number ; where = both | above | below
% ---------------------------------------------------------------------
\tkzfn@family{area}{
  domain/.store in  = \tkzfn@domain,
  samples/.store in = \tkzfn@samples,
  where/.store in   = \tkzfn@where,
  clip/.store in    = \tkzfn@clip,
  clip/.default     = true}
\def\tkzFnArea{\@ifnextchar[{\tkzfn@area}{\tkzfn@area[]}}
\def\tkzfn@area[#1]{\tkzfn@sp{\tkzfn@area@{#1}}}
\def\tkzfn@area@#1(#2){\tkzfn@area@split{#1}#2,,\@nil}
\def\tkzfn@area@split#1#2,#3,#4\@nil{%
  \begingroup
  \tkzfn@keys{area}{domain=,samples=200,where=both,clip=true}{#1}%
  \tkzfn@lua{tkzfn.area{
    f       = "\tkzfn@E{#2}",
    g       = "\tkzfn@E{#3}",
    domain  = "\tkzfn@E\tkzfn@domain",
    samples = "\tkzfn@E\tkzfn@samples",
    where   = "\tkzfn@E\tkzfn@where",
    clip    = "\tkzfn@E\tkzfn@clip",
    opts    = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

% ---------------------------------------------------------------------
% Riemann sums : \tkzFnRiemann[method,interval=a:b,number=n,<TikZ>](f)
% method = left | right | mid | inf | sup
% ---------------------------------------------------------------------
\tkzfn@family{riemann}{
  method/.store in   = \tkzfn@method,
  interval/.store in = \tkzfn@interval,
  number/.store in   = \tkzfn@number,
  clip/.store in     = \tkzfn@clip,
  clip/.default      = true}
\def\tkzFnRiemann{\@ifnextchar[{\tkzfn@riemann}{\tkzfn@riemann[]}}
\def\tkzfn@riemann[#1]{\tkzfn@sp{\tkzfn@riemann@{#1}}}
\def\tkzfn@riemann@#1(#2){%
  \begingroup
  \tkzfn@keys{riemann}{method=left,interval=,number=10,clip=false}{#1}%
  \tkzfn@lua{tkzfn.riemann{
    f        = "\tkzfn@E{#2}",
    method   = "\tkzfn@E\tkzfn@method",
    interval = "\tkzfn@E\tkzfn@interval",
    number   = "\tkzfn@E\tkzfn@number",
    clip     = "\tkzfn@E\tkzfn@clip",
    opts     = "\tkzfn@DM\tkzfn@tikz"}}%
  \endgroup}

% ---------------------------------------------------------------------
% lines x = a and y = b ; data
% \tkzFnVLines[<TikZ>]{list}  \tkzFnHLines[<TikZ>]{list}  (list: 1,2,...,5)
% \tkzFnDrawData[<TikZ>]{x1/y1,x2/y2,...}
% ---------------------------------------------------------------------
\def\tkzFnVLines{\@ifnextchar[{\tkzfn@vlines}{\tkzfn@vlines[]}}
\def\tkzfn@vlines[#1]#2{%
  \tkzfn@lua{tkzfn.vlines{list = "\tkzfn@E{#2}", opts = "\tkzfn@D{#1}"}}}
\let\tkzFnVLine\tkzFnVLines
\def\tkzFnHLines{\@ifnextchar[{\tkzfn@hlines}{\tkzfn@hlines[]}}
\def\tkzfn@hlines[#1]#2{%
  \tkzfn@lua{tkzfn.hlines{list = "\tkzfn@E{#2}", opts = "\tkzfn@D{#1}"}}}
\let\tkzFnHLine\tkzFnHLines

\def\tkzFnDrawData{\@ifnextchar[{\tkzfn@data}{\tkzfn@data[]}}
\def\tkzfn@data[#1]#2{%
  \tkzfn@lua{tkzfn.data{list = "\tkzfn@E{#2}", opts = "\tkzfn@D{#1}"}}}

% ---------------------------------------------------------------------
% printing of results (fr / us)
% \tkzFnPrint[decimals]{Lua expression}     ex. \tkzFnPrint{f(2)}
% \tkzFnPrintInterval[oo|cc|oc|co]{a}{b}
% ---------------------------------------------------------------------
\def\tkzFnPrint{\@ifnextchar[{\tkzfn@print}{\tkzfn@print[]}}
\def\tkzfn@print[#1]#2{%
  \tkzfn@lua{tkzfn.print_number("\tkzfn@E{#2}","\tkzfn@E{#1}")}}

\def\tkzFnPrintInterval{\@ifnextchar[{\tkzfn@printint}{\tkzfn@printint[cc]}}
\def\tkzfn@printint[#1]#2#3{%
  \tkzfn@lua{tkzfn.print_interval("\tkzfn@D{#2}","\tkzfn@D{#3}","\tkzfn@E{#1}")}}

\endinput