Package xkeyval : booléen pour « si - alors - sinon » et affectation d'une variable

\documentclass[12pt,a4paper]{article}
\usepackage[latin1,utf8]{inputenc}
\usepackage[french]{babel}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{lmodern}
\usepackage{fourier}
\usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}
\usepackage{tikz}
    \usetikzlibrary{patterns}
\usepackage{tkz-euclide}
    \usetkzobj{all}
\usepackage{xkeyval}
\usepackage{ifthen}

\makeatletter
%----------> \CrayonGris <----------
\definecolor{wood}{cmyk}{0.00,0.12,0.35,0.05}
\define@cmdkey [DES] {CrayonGris} {inclinaison}{}    
\define@cmdkey [DES] {CrayonGris} {mine}{}
\define@cmdkey [DES] {CrayonGris} {corps}{}
\define@cmdkey [DES] {CrayonGris} {couleur}{}
\define@cmdkey [DES] {CrayonGris} {xscale}{}
\define@cmdkey [DES] {CrayonGris} {yscale}{}
\define@boolkey [DES] {CrayonGris} {bague}[true]{}
\define@boolkey [DES] {CrayonGris} {orientation}[true]{}
\presetkeys    [DES] {CrayonGris} {inclinaison = 0, mine = red, corps = blue, couleur = wood, xscale=1, yscale=1}{}
%
\newcommand{\CrayonGris}[2][]{%
    \setkeys[DES]{CrayonGris}{#1}
    \begin{scope}[shift={(#2)},rotate=\cmdDES@CrayonGris@inclinaison, xscale=\cmdDES@CrayonGris@xscale, yscale=\cmdDES@CrayonGris@yscale]
% Pointe ouverte
    \draw[fill=\cmdDES@CrayonGris@couleur] (-0.3,0.6) -- (0,0) -- (0.3,0.6) arc(-90:-180:0.1) arc(0:-180:0.1) arc(0:-180:0.1) arc(0:-90:0.1);
% Mine
    \draw[fill=\cmdDES@CrayonGris@mine] (-0.1,0.2) -- (0.1,0.2) -- (0,0) -- cycle;
% Corps du crayon    
    \draw[fill=\cmdDES@CrayonGris@corps] (0.3,0.6) arc(-90:-180:0.1) arc(0:-180:0.1) arc(0:-180:0.1) arc(0:-90:0.1) -- (-0.3,6) -- (0.3,6) -- cycle;
% Traits verticaux
    \draw (-0.2,6) -- (-0.2,0.65) (0,6) -- (0,0.65) (0.2,6) -- (0.2,0.65);
% Bague
    \if boolDES@CrayonGris@bague
    {
    \draw[fill=gray!20,opacity=0.5] (-0.4,1.5)rectangle(0.4,2.5);
    % Vis
    \if boolDES@CrayonGris@orientation
        {
        let \n = 1
        \draw (1,1) node{A};
        }
        \else
        {
        let \n = -1
        \draw(-1,-1) node{B}
        }
   \fi
\draw[fill=gray!20] (0.4*\n,1.9)--(0.6*\n,1.9)--(0.6*\n,1.8)--(0.8*\n,1.8)--(0.8*\n,2.2)--(0.6*\n,2.2)--(0.6*\n,2.1)--(0.4*\n,2.1)--cycle;
%\draw[fill=gray!20] (0.4,1.9)--(0.6,1.9)--(0.6,1.8)--(0.8,1.8)--(0.8,2.2)--(0.6,2.2)--(0.6,2.1)--(0.4,2.1)--cycle;
}
    \else
    \fi
%\ifthenelse{cmdDES@CrayonGris@orientation}{\n = 1}{\n = 2}
    \end{scope}
}
\makeatother

\begin{document}

\section*{Crayon gris avec bague et vis}

\begin{tikzpicture}
    \CrayonGris{0,0} 
    \CrayonGris[inclinaison=60,corps=gray,mine=black,couleur=white,xscale=1,yscale=1]{0,0}
    \CrayonGris[inclinaison=-80,corps=orange,mine=yellow,couleur=white,xscale=1.5,yscale=.75]{0,0}
\end{tikzpicture}

\begin{tikzpicture}
    \CrayonGris[bague=true,orientation=false,inclinaison=-90,corps=red,xscale=2,yscale=1.5]{0,0} 
    \CrayonGris[bague=true,orientation=true,corps=green]{0,0}
    \CrayonGris[bague=false,orientation=true,corps=white,inclinaison=90]{0,0} 
    \CrayonGris[bague=false,orientation=true,inclinaison=180]{0,0}
\end{tikzpicture}

\end{document}