% --------------------------------------------------------------------------
% the CARBOHYDRATES package
% 
%   ready drawn carbohydrates with chemfig
%
% --------------------------------------------------------------------------
% Clemens Niederberger
% Web:    https://github.com/cgnieder/carbohydrates
% E-Mail: contact@mychemistry.eu
% --------------------------------------------------------------------------
% Copyright 2014-2015 Clemens Niederberger
% 
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3
% of this license or (at your option) any later version.
% The latest version of this license is in
%   http://www.latex-project.org/lppl.txt
% and version 1.3 or later is part of all distributions of LaTeX
% version 2005/12/01 or later.
% 
% This work has the LPPL maintenance status `maintained'.
% 
% The Current Maintainer of this work is Clemens Niederberger.
% --------------------------------------------------------------------------
% If you have any ideas, questions, suggestions or bugs to report, please
% feel free to contact me.
% --------------------------------------------------------------------------
\def\cbhdr@date{2015/12/01}
\def\cbhdr@version{v0.1}
\def\cbhdr@info{carbohydrate molecules with chemfig}

\ProvidesPackage{carbohydrates}[%
  \cbhdr@date\space
  \cbhdr@version\space
  \cbhdr@info\space (CN)]

\RequirePackage{etoolbox}
\RequirePackage{chemfig,xcolor}

% ==========================================================================
% message handling
% generic help message:
\newrobustcmd\cbhdr@create@message[2]{%
  \ifstrequal{#1}{Error}
    {%
      \lowercase{\csdef{cbhdr@#1}}##1{%
        \csuse{Package#1}{carbohydrates}{##1}{#2}}%
    }{%
      \lowercase{\csdef{cbhdr@#1}}##1{%
        \csuse{Package#1}{carbohydrates}{##1}}%
    }}

\newcommand*\cbhdr@error@message{%
  For details have a look at the `carbohydrates' manual.%
}

% create message macros:
\cbhdr@create@message{Error}{\cbhdr@error@message}
\cbhdr@create@message{Warning}{}
\cbhdr@create@message{WarningNoLine}{}
\cbhdr@create@message{Info}{}

\newcommand*\cbhdr@ring@error[2]{%
  \cbhdr@error{#1 can't form #2 rings}%
}

\newcommand*\cbhdr@define@ring@error[3]{%
  \protected\csdef{cbhdr@aldo#2@#1@ring@#3}{\cbhdr@ring@error{#2s}{#3}}%
}

\newcommand*\cbhdr@define@chain@error[2]{%
  \protected\csdef{cbhdr@aldo#2@#1@chain}{%
    \cbhdr@error{The chain is not implemented for #2s in the #1 model}%
  }%
}

\newcommand*\cbhdr@chair@error[1]{%
  \cbhdr@error{The chair model is not implemented for #1}%
}

\newcommand*\cbhdr@define@chair@errors[1]{%
  \protected\csdef{cbhdr@aldo#1@chair@chain}{\cbhdr@chair@error{#1s}}%
  \protected\csdef{cbhdr@aldo#1@chair@ring@pyranose}{\cbhdr@chair@error{#1s}}%
  \protected\csdef{cbhdr@aldo#1@chair@ring@furanose}{\cbhdr@chair@error{#1s}}%
}

\newrobustcmd\cbhdr@expand@x[2]{%
  \begingroup\edef\cbhdr@expand@tmp{\endgroup\unexpanded{#1}{#2}}%
  \cbhdr@expand@tmp
}
\newrobustcmd\cbhdr@expand@nx[3]{%
  \begingroup\edef\cbhdr@expand@tmp{\endgroup\unexpanded{#1{#2}}{#3}}%
  \cbhdr@expand@tmp
}

\newcommand*\cbhdr@stripbs{\expandafter\@gobble\string}

% ==========================================================================
% colors
\newrobustcmd*\cbhdr@defcolor[2]{\colorlet{cbhdr@#1}{#2}}

\cbhdr@defcolor{C1}{black}
\cbhdr@defcolor{C6}{black}
\cbhdr@defcolor{O-C6}{black}
\cbhdr@defcolor{H-C6}{black}
\cbhdr@defcolor{anomerO}{black}
\cbhdr@defcolor{anomerH}{black}
\cbhdr@defcolor{ringO}{black}

\newcommand*\cbhdr@atom@color[2]{\unexpanded{\textcolor{cbhdr@#1}{#2}}}

% ==========================================================================
% wavy bonds:
\usetikzlibrary{decorations.pathmorphing}
\pgfdeclaredecoration{cbhdr wave}{initial}{
  \state{initial}[
    width = +0pt ,
    next state = sine,
    persistent precomputation = {
      \pgfmathsetmacro\matchinglength{
        \pgfdecoratedinputsegmentlength /
        int(\pgfdecoratedinputsegmentlength/\pgfdecorationsegmentlength)
      }
      \setlength{\pgfdecorationsegmentlength}{\matchinglength pt}
    }
  ]{}
  \state{sine}[width=\pgfdecorationsegmentlength]{
    \pgfpathsine{
      \pgfpoint
        {0.25\pgfdecorationsegmentlength}
        {0.5\pgfdecorationsegmentamplitude}
      }
    \pgfpathcosine{
      \pgfpoint
        {0.25\pgfdecorationsegmentlength}
        {-0.5\pgfdecorationsegmentamplitude}
      }
    \pgfpathsine{
      \pgfpoint
        {0.25\pgfdecorationsegmentlength}
        {-0.5\pgfdecorationsegmentamplitude}
      }
    \pgfpathcosine{
      \pgfpoint
        {0.25\pgfdecorationsegmentlength}
        {0.5\pgfdecorationsegmentamplitude}
      }
  }
  \state{final}{}
}

\tikzset{
  cbhdr/wavy bond/.style =
    {
      decorate,
      decoration =
        {
          amplitude   = 0.23*\CF@atom@sep/3 ,
          post length = 0 pt,
          pre length  = 0 pt,
          % Use the atom spacing: saved 
          segment length = \CF@atom@sep/5 ,
          cbhdr wave
        }
    }
}

% ==========================================================================
% sub molecules for all the modular building of the molecules later
\newcommand*\cbhdr@C[1]{\cbhdr@atom@color{C#1}{C}}

\newcommand*\cbhdr@OH[1]{%
  \cbhdr@atom@color{O-C#1}{O}|%
  \cbhdr@atom@color{H-C#1}{H}%
}
\newcommand*\cbhdr@HO[1]{%
  \cbhdr@atom@color{H-C#1}{H}|%
  \cbhdr@atom@color{O-C#1}{O}%
}
\newcommand*\cbhdr@ring@O{\cbhdr@atom@color{ringO}{O}}
\newcommand*\cbhdr@anomer@O{\cbhdr@atom@color{anomerO}{O}}
\newcommand*\cbhdr@anomer@OH{%
  \cbhdr@atom@color{anomerO}{O}|%
  \cbhdr@atom@color{anomerH}{H}%
}
\newcommand*\cbhdr@anomer@HO{%
  \cbhdr@atom@color{anomerH}{H}|%
  \cbhdr@atom@color{anomerO}{O}%
}

\newrobustcmd*\cbhdr@definesubmol@expand{\cbhdr@expand@nx\definesubmol}
\newrobustcmd*\cbhdr@chemfig@expand{\cbhdr@expand@x\chemfig}

\newrobustcmd\cbhdr@define@Csubmols[1]{%
  \cbhdr@defcolor{O-C#1}{black}%
  \cbhdr@defcolor{H-C#1}{black}%
  \cbhdr@defcolor{C#1}{black}%
  % aldohexoses:
  % fischer:
  % skeletons
  \cbhdr@definesubmol@expand{cbhdr@fischer@skeleton@C#1@OHr}{(-[:0]\cbhdr@OH{#1})}%
  \cbhdr@definesubmol@expand{cbhdr@fischer@skeleton@C#1@OHl}{(-[:180]\cbhdr@HO{#1})}%
  \cbhdr@definesubmol@expand{cbhdr@fischer@skeleton@C#1@OH0}{}%
  % with C and H
  \cbhdr@definesubmol@expand{cbhdr@fischer@C#1@OHr}{(-[:0]\cbhdr@OH{#1})(-[:180]H)}%
  \cbhdr@definesubmol@expand{cbhdr@fischer@C#1@OHl}{(-[:180]\cbhdr@HO{#1})(-[:0]H)}%
  \cbhdr@definesubmol@expand{cbhdr@fischer@C#1@OH0}{(-[:180]H)(-[:0]H)}%
  % haworth:
  \ifnum#1=5\relax
    \cbhdr@definesubmol@expand{cbhdr@haworth@C#1@OHr}{(-[:0]\cbhdr@OH{#1})}%
    \cbhdr@definesubmol@expand{cbhdr@haworth@C#1@OHl}{(-[:180,.5]\cbhdr@HO{#1})}%
  \else
    \cbhdr@definesubmol@expand{cbhdr@haworth@C#1@OHr}{(-[:-90,.5,,1]\cbhdr@OH{#1})}%
    \cbhdr@definesubmol@expand{cbhdr@haworth@C#1@OHl}{(-[:90,.5,,1]\cbhdr@OH{#1})}%
  \fi
  \definesubmol{cbhdr@haworth@C#1@OH0}{}%
  % chair:
  \ifcase#1
  \or % 1
  \or % 2
    \cbhdr@definesubmol@expand{cbhdr@chair@C#1@OHr}{(-[:-55,.75,,1]\cbhdr@OH{#1})}%
    \cbhdr@definesubmol@expand{cbhdr@chair@C#1@OHl}{(-[:90,.5,,1]\cbhdr@OH{#1})}%
  \or % 3
    \cbhdr@definesubmol@expand{cbhdr@chair@C#1@OHr}{(-[:-90,.5,,1]\cbhdr@OH{#1})}%
    \cbhdr@definesubmol@expand{cbhdr@chair@C#1@OHl}{(-[:170,.75,,2]\cbhdr@HO{#1})}%
  \or % 4
    \cbhdr@definesubmol@expand{cbhdr@chair@C#1@OHr}{(-[:190,.75,,2]\cbhdr@HO{#1})}%
    \cbhdr@definesubmol@expand{cbhdr@chair@C#1@OHl}{(-[:90,.5,,1]\cbhdr@OH{#1})}%
  \or % 5
    \cbhdr@definesubmol@expand{cbhdr@chair@C#1@OHr}{(-[:10,.75,,1]\cbhdr@OH{#1})}%
    \cbhdr@definesubmol@expand{cbhdr@chair@C#1@OHl}{(-[:-90,.5,,1]\cbhdr@OH{#1})}%
  \fi
  \definesubmol{cbhdr@chair@C#1@OH0}{}%
}
\cbhdr@define@Csubmols{2}
\cbhdr@define@Csubmols{3}
\cbhdr@define@Csubmols{4}
\cbhdr@define@Csubmols{5}

\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C2@OHr}{(-[:-90,.5]\cbhdr@OH{2})}
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C2@OHl}{(-[:90,.5,,2]\cbhdr@HO{2})}
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C2@OH0}{}

\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C3@OHr}{(-[:-90,.5]\cbhdr@OH{3})}
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C3@OHl}{(-[:90,.5]\cbhdr@OH{3})}
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C3@OH0}{}

\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C4@OHr}{(-[:20]\cbhdr@OH{4})}
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C4@OH0}{}

% 4=r, 5=r
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C4@OHr@C5@OHr}{(
  -[:90,.5](<[:30,.5]\cbhdr@OH{5})
  -[:120,.5]
  -[:-180,.5,,2]HO
)}
% 4=l, 5=r
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C4@OHl@C5@OHr}{(
  -[:-90,.5](<:[:150,.5]\cbhdr@HO{5})
  -[:-120,.5]
  -[:180,.5,,2]HO
)}

% 4=r, 5=l
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C4@OHr@C5@OHl}{(
  -[:90,.5](<:[:30,.5]\cbhdr@OH{5})
  -[:120,.5]
  -[:-180,.5,,2]HO
)}
% 4=l, 5=l
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C4@OHl@C5@OHl}{(
  -[:-90,.5](<[:150,.5]\cbhdr@HO{5})
  -[:-120,.5]
  -[:180,.5,,2]HO
)}

% 4=r, 5=0
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C4@OHr@C5@OH0}{(
  -[:90,.5]
  -[:120,.5]
  -[:-180,.5]HO
)}
% 4=l, 5=0
\cbhdr@definesubmol@expand{cbhdr@haworth@furanose@C4@OHl@C5@OH0}{(
  -[:-90,.5]
  -[:-120,.5]
  -[:180,.5]HO
)}
% 4=0 wouldn't make sense since then the furanose ring cannot be formed

% fischer
\cbhdr@definesubmol@expand{cbhdr@fischer@skeleton@aldehyde}{(=_[:30]\cbhdr@anomer@O)}
\cbhdr@definesubmol@expand{cbhdr@fischer@skeleton@OHalpha}{(-[:0]\cbhdr@anomer@OH)}
\cbhdr@definesubmol@expand{cbhdr@fischer@skeleton@OHbeta}{(-[:180]\cbhdr@anomer@HO)}
\cbhdr@definesubmol@expand{cbhdr@fischer@skeleton@OHundetermined}{(-[:0]\cbhdr@anomer@OH)}

\cbhdr@definesubmol@expand{cbhdr@fischer@aldehyde}{(=[:30]\cbhdr@anomer@O)(-[:150]H)}
\cbhdr@definesubmol@expand{cbhdr@fischer@OHalpha}{(-[:0]\cbhdr@anomer@OH)(-[:180]H)}
\cbhdr@definesubmol@expand{cbhdr@fischer@OHbeta}{(-[:180]\cbhdr@anomer@HO)(-[:0]H)}
\cbhdr@definesubmol@expand{cbhdr@fischer@OHundetermined}{(-[:0]\cbhdr@anomer@HO)(-[:180]H)}

% haworth
\cbhdr@definesubmol@expand{cbhdr@haworth@OHalpha}{(-[:-90,.5,,1]\cbhdr@anomer@OH)}
\cbhdr@definesubmol@expand{cbhdr@haworth@OHbeta}{(-[:90,.5,,1]\cbhdr@anomer@OH)}
\cbhdr@definesubmol@expand{cbhdr@haworth@OHundetermined}
  {(-[:0,.75,,1,cbhdr/wavy bond]\cbhdr@anomer@OH)}

% chair:
\cbhdr@definesubmol@expand{cbhdr@chair@OHalpha}{(-[:-90,.5,,1]\cbhdr@anomer@OH)}
\cbhdr@definesubmol@expand{cbhdr@chair@OHbeta}{(-[:10,.75,,1]\cbhdr@anomer@OH)}
\cbhdr@definesubmol@expand{cbhdr@chair@OHundetermined}
  {(-[:0,.75,,1,cbhdr/wavy bond]\cbhdr@anomer@OH)}

% ==========================================================================
% commands to define the chain and ring molecules avoiding code duplication:

% the arguments of a chain refer to r and l for the chiral centers. A hexose
% needs four arguments: \cbhdr@newchain\hexose#1#2#3#4{<code>}

% \cbhdr@newchain<macro><arguments>{<chemfig code>}

\protected\def\cbhdr@newchain#1{\cbhdr@newchain@aux@i{#1}}
\protected\def\cbhdr@newchain@aux@i#1#2#{\cbhdr@newchain@aux@ii{#1}{#2}}
\protected\def\cbhdr@newchain@aux@ii#1#2#3{%
  \protected\csdef{\cbhdr@stripbs#1@aux}#2\q@stop{\cbhdr@chemfig@expand{#3}}%
  \newrobustcmd*#1[1]{\csuse{\cbhdr@stripbs#1@aux}##1\q@stop}%
}

% the first argument of a ring always is alpha/beta, the following arguments
% refer to r and l for the chiral centers. A hexose needs five arguments:
% \cbhdr@newring\hexose#1#2#3#4#5{<code>}

% \cbhdr@newring<macro><arguments>{<chemfig code>}

\protected\def\cbhdr@newring#1{\cbhdr@newring@aux@i{#1}}
\protected\def\cbhdr@newring@aux@i#1#2#{\cbhdr@newring@aux@ii{#1}{#2}}
\protected\def\cbhdr@newring@aux@ii#1#2#3{%
  \protected\csdef{\cbhdr@stripbs#1@aux}#2\q@stop{\cbhdr@chemfig@expand{#3}}%
  \newrobustcmd*#1[1]{\csuse{\cbhdr@stripbs#1@aux}{\cbhdr@anomer}##1\q@stop}%
}

% ==========================================================================
% now let's build the molecules using the submolecules from above. They're
% all named using the following naming scheme:
%
% \<module>@<model>@<chain>/<ring>(@<ringtype>)
%
% --------------------------------------------------------------------------
% Fischer - skeleton formulas

%%%
% hexoses
% chain
\cbhdr@newchain\cbhdr@aldohexose@fischer@skeleton@chain#1#2#3#4{
  !{cbhdr@fischer@skeleton@aldehyde}
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#1}
  -[:-90]!{cbhdr@fischer@skeleton@C3@OH#2}
  -[:-90]!{cbhdr@fischer@skeleton@C4@OH#3}
  -[:-90]!{cbhdr@fischer@skeleton@C5@OH#4}
  -[:-90](-[:0]\cbhdr@OH{6})
}

% pyranoses
\cbhdr@newring\cbhdr@aldohexose@fischer@skeleton@ring@pyranose#1#2#3#4#5{%
  !{cbhdr@fischer@skeleton@OH#1}(-[:90]-[:0]-?)
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#2}
  -[:-90]!{cbhdr@fischer@skeleton@C3@OH#3}
  -[:-90]!{cbhdr@fischer@skeleton@C4@OH#4}
  -[:-90](-[:0]\cbhdr@ring@O-?)
  -[:-90](-[:0]\cbhdr@OH{6})
}

% furanoses
\cbhdr@newring\cbhdr@aldohexose@fischer@skeleton@ring@furanose#1#2#3#4#5{%
  !{cbhdr@fischer@skeleton@OH#1}(-[:90]-[:0]-?)
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#2}
  -[:-90]!{cbhdr@fischer@skeleton@C3@OH#3}
  -[:-90](-[:0]\cbhdr@ring@O-?)
  -[:-90]!{cbhdr@fischer@skeleton@C5@OH#5}
  -[:-90](-[:0]\cbhdr@OH{6})
}

%%%
% pentoses
% chain
\cbhdr@newchain\cbhdr@aldopentose@fischer@skeleton@chain#1#2#3{%
  !{cbhdr@fischer@skeleton@aldehyde}
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#1}
  -[:-90]!{cbhdr@fischer@skeleton@C3@OH#2}
  -[:-90]!{cbhdr@fischer@skeleton@C4@OH#3}
  -[:-90](-[:0]\cbhdr@OH{5})
}

% pyranoses
\cbhdr@newring\cbhdr@aldopentose@fischer@skeleton@ring@pyranose#1#2#3#4{%
  !{cbhdr@fischer@skeleton@OH#1}(-[:90]-[:0]-?)
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#2}
  -[:-90]!{cbhdr@fischer@skeleton@C3@OH#3}
  -[:-90]!{cbhdr@fischer@skeleton@C4@OH#4}
  -[:-90](-[:0]\cbhdr@ring@O-?)
}

% furanoses
\cbhdr@newring\cbhdr@aldopentose@fischer@skeleton@ring@furanose#1#2#3#4{%
  !{cbhdr@fischer@skeleton@OH#1}(-[:90]-[:0]-?)
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#2}
  -[:-90]!{cbhdr@fischer@skeleton@C3@OH#3}
  -[:-90](-[:0]\cbhdr@ring@O-?)
  -[:-90](-[:0]\cbhdr@OH{5})
}

%%%
% tetroses
% chain
\cbhdr@newchain\cbhdr@aldotetrose@fischer@skeleton@chain#1#2{%
  !{cbhdr@fischer@skeleton@aldehyde}
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#1}
  -[:-90]!{cbhdr@fischer@skeleton@C3@OH#2}
  -[:-90](-[:0]\cbhdr@OH{4})
}

% pyranoses
\cbhdr@define@ring@error{fischer@skeleton}{tetrose}{pyranose}

% furanoses
\cbhdr@newring\cbhdr@aldotetrose@fischer@skeleton@ring@furanose#1#2#3{%
  !{cbhdr@fischer@skeleton@OH#1}(-[:90]-[:0]-?)
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#2}
  -[:-90]!{cbhdr@fischer@skeleton@C3@OH#3}
  -[:-90](-[:0]\cbhdr@ring@O-?)
}

%%%
% trioses
% chain
\cbhdr@newchain\cbhdr@aldotriose@fischer@skeleton@chain#1{%
  !{cbhdr@fischer@skeleton@aldehyde}
  -[:-90]!{cbhdr@fischer@skeleton@C2@OH#1}
  -[:-90](-[:0]\cbhdr@OH{3})
}

% pyranoses
\cbhdr@define@ring@error{fischer@skeleton}{triose}{pyranose}

% furanoses
\cbhdr@define@ring@error{fischer@skeleton}{triose}{furanose}

% --------------------------------------------------------------------------
% Fischer - with C and H

%%%
% hexoses
% chain
\cbhdr@newchain\cbhdr@aldohexose@fischer@chain#1#2#3#4{%
  \cbhdr@C{1}!{cbhdr@fischer@aldehyde}
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#1}
  -[:-90]\cbhdr@C{3}!{cbhdr@fischer@C3@OH#2}
  -[:-90]\cbhdr@C{4}!{cbhdr@fischer@C4@OH#3}
  -[:-90]\cbhdr@C{5}!{cbhdr@fischer@C5@OH#4}
  -[:-90]\cbhdr@C{6}(-[:0]\cbhdr@OH{6})(-[:180]H)
  -[:-90]H
}

% pyranoses
\cbhdr@newring\cbhdr@aldohexose@fischer@ring@pyranose#1#2#3#4#5{%
  \cbhdr@C{1}!{cbhdr@fischer@OH#1}(-[:90]-[:0]-?)
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#2}
  -[:-90]\cbhdr@C{3}!{cbhdr@fischer@C3@OH#3}
  -[:-90]\cbhdr@C{4}!{cbhdr@fischer@C4@OH#4}
  -[:-90]\cbhdr@C{5}(-[:0]\cbhdr@ring@O-?)(-[:180]H)
  -[:-90]\cbhdr@C{6}(-[:0]\cbhdr@OH{6})(-[:180]H)
  -[:-90]H
}

% furanoses
\cbhdr@newring\cbhdr@aldohexose@fischer@ring@furanose#1#2#3#4#5{%
  \cbhdr@C{1}!{cbhdr@fischer@OH#1}(-[:90]-[:0]-?)
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#2}
  -[:-90]\cbhdr@C{3}!{cbhdr@fischer@C3@OH#3}
  -[:-90]\cbhdr@C{4}(-[:0]\cbhdr@ring@O-?)(-[:180]H)
  -[:-90]\cbhdr@C{5}!{cbhdr@fischer@C5@OH#5}
  -[:-90]\cbhdr@C{6}(-[:0]\cbhdr@OH{6})(-[:180]H)
  -[:-90]H
}

%%%
% pentoses
% chain
\cbhdr@newchain\cbhdr@aldopentose@fischer@chain#1#2#3{%
  \cbhdr@C{1}!{cbhdr@fischer@aldehyde}
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#1}
  -[:-90]\cbhdr@C{3}!{cbhdr@fischer@C3@OH#2}
  -[:-90]\cbhdr@C{4}!{cbhdr@fischer@C4@OH#3}
  -[:-90]\cbhdr@C{5}(-[:0]\cbhdr@OH{5})(-[:180]H)
  -[:-90]H
}

% pyranoses
\cbhdr@newring\cbhdr@aldopentose@fischer@ring@pyranose#1#2#3#4{%
  \cbhdr@C{1}!{cbhdr@fischer@OH#1}(-[:90]-[:0]-?)
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#2}
  -[:-90]\cbhdr@C{3}!{cbhdr@fischer@C3@OH#3}
  -[:-90]\cbhdr@C{4}!{cbhdr@fischer@C4@OH#4}
  -[:-90]\cbhdr@C{5}(-[:0]\cbhdr@ring@O-?)(-[:180]H)
  -[:-90]H
}

% furanoses
\cbhdr@newring\cbhdr@aldopentose@fischer@ring@furanose#1#2#3#4{%
  \cbhdr@C{1}!{cbhdr@fischer@OH#1}(-[:90]-[:0]-?)
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#2}
  -[:-90]\cbhdr@C{3}!{cbhdr@fischer@C3@OH#3}
  -[:-90]\cbhdr@C{4}(-[:0]\cbhdr@ring@O-?)(-[:180]H)
  -[:-90]\cbhdr@C{5}(-[:0]\cbhdr@OH{5})(-[:180]H)
  -[:-90]H
}

%%%
% tetroses
% chain
\cbhdr@newchain\cbhdr@aldotetrose@fischer@chain#1#2{%
  \cbhdr@C{1}!{cbhdr@fischer@aldehyde}
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#1}
  -[:-90]\cbhdr@C{3}!{cbhdr@fischer@C3@OH#2}
  -[:-90]\cbhdr@C{4}(-[:0]\cbhdr@OH{4})(-[:180]H)
  -[:-90]H
}

% pyranoses
\cbhdr@define@ring@error{fischer}{tetrose}{pyranose}

% furanoses
\cbhdr@newring\cbhdr@aldotetrose@fischer@ring@furanose#1#2#3{%
  \cbhdr@C{1}!{cbhdr@fischer@OH#1}(-[:90]-[:0]-?)
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#2}
  -[:-90]\cbhdr@C{3}!{cbhdr@fischer@C3@OH#3}
  -[:-90]\cbhdr@C{4}(-[:0]\cbhdr@ring@O-?)(-[:180]H)
  -[:-90]H
}

%%%
% trioses
% chain
\cbhdr@newchain\cbhdr@aldotriose@fischer@chain#1{%
  \cbhdr@C{1}!{cbhdr@fischer@aldehyde}
  -[:-90]\cbhdr@C{2}!{cbhdr@fischer@C2@OH#1}
  -[:-90]\cbhdr@C{3}(-[:0]\cbhdr@OH{3})(-[:180]H)
  -[:-90]H
}

% pyranoses
\cbhdr@define@ring@error{fischer}{triose}{pyranose}

% furanoses
\cbhdr@define@ring@error{fischer}{triose}{furanose}

% --------------------------------------------------------------------------
% Haworth
\newcommand*\cbhdr@decr{-} % >
\newcommand*\cbhdr@thick{} % line width=3pt
\newcommand*\cbhdr@incr{-} % <

%%%
% hexoses
% chain
\cbhdr@newchain\cbhdr@aldohexose@haworth@chain#1#2#3#4{%
  -[:30]
  ?(-[:90,.5]-[:150,.5]\cbhdr@HO{6})!{cbhdr@haworth@C5@OH#4}-[,,,,draw=none]
  -[:-30,,1,,draw=none](=_[:0]\cbhdr@anomer@O)
  \cbhdr@incr[:-150]!{cbhdr@haworth@C2@OH#1}
  -[:-180,,,,\cbhdr@thick]!{cbhdr@haworth@C3@OH#2}
  \cbhdr@decr[:150]?!{cbhdr@haworth@C4@OH#3}
}

% pyranoses
\cbhdr@newring\cbhdr@aldohexose@haworth@ring@pyranose#1#2#3#4#5{%
  -[:30]
  ?(-[:90,.5]-[:150,.5]\cbhdr@HO{6})-\cbhdr@ring@O
  -[:-30]!{cbhdr@haworth@OH#1}
  \cbhdr@incr[:-150]!{cbhdr@haworth@C2@OH#2}
  -[:-180,,,,\cbhdr@thick]!{cbhdr@haworth@C3@OH#3}
  \cbhdr@decr[:150]?!{cbhdr@haworth@C4@OH#4}
}

% furanoses
\cbhdr@newring\cbhdr@aldohexose@haworth@ring@furanose#1#2#3#4#5{%
  \cbhdr@ring@O?-[:-20]!{cbhdr@haworth@OH#1}
  -[:-110]!{cbhdr@haworth@furanose@C2@OH#2}
  -[:180,1.1954]!{cbhdr@haworth@furanose@C3@OH#3}
  -[:110]?!{cbhdr@haworth@furanose@C4@OH#4@C5@OH#5}
}

%%%
% pentoses
% chain
\cbhdr@newchain\cbhdr@aldopentose@haworth@chain#1#2#3{%
  ?-[:-20,,,,draw=none](=_[:0]\cbhdr@anomer@O)
  -[:-110]!{cbhdr@haworth@furanose@C2@OH#1}
  -[:180,1.1954]!{cbhdr@haworth@furanose@C3@OH#2}
  -[:110]?[,,{draw=none}](-[:90,.5]-[:150,.5]\cbhdr@HO{5})
  !{cbhdr@haworth@furanose@C4@OH#3}
}

% pyranoses
\cbhdr@newring\cbhdr@aldopentose@haworth@ring@pyranose#1#2#3#4{%
  -[:30]
  ?-\cbhdr@ring@O
  -[:-30]!{cbhdr@haworth@OH#1}
  \cbhdr@incr[:-150]!{cbhdr@haworth@C2@OH#2}
  -[:-180,,,,\cbhdr@thick]!{cbhdr@haworth@C3@OH#3}
  \cbhdr@decr[:150]?!{cbhdr@haworth@C4@OH#4}
}

% furanoses
\cbhdr@newring\cbhdr@aldopentose@haworth@ring@furanose#1#2#3#4{%
  \cbhdr@ring@O?-[:-20]!{cbhdr@haworth@OH#1}
  -[:-110]!{cbhdr@haworth@furanose@C2@OH#2}
  -[:180,1.1954]!{cbhdr@haworth@furanose@C3@OH#3}
  -[:110]?(-[:90,.5]-[:150,.5]\cbhdr@HO{5})
}

%%%
% tetroses
% chain
\cbhdr@define@chain@error{haworth}{tetrose}

% pyranoses
\cbhdr@define@ring@error{haworth}{tetrose}{pyranose}

% furanoses
\cbhdr@newring\cbhdr@aldotetrose@haworth@ring@furanose#1#2#3{%
  \cbhdr@ring@O?-[:-20]!{cbhdr@haworth@OH#1}
  -[:-110]!{cbhdr@haworth@furanose@C2@OH#2}
  -[:180,1.1954]!{cbhdr@haworth@furanose@C3@OH#3}
  -[:110]?
}

%%%
% trioses
% chain
\cbhdr@define@chain@error{haworth}{triose}

% pyranoses
\cbhdr@define@ring@error{haworth}{triose}{pyranose}

% furanoses
\cbhdr@define@ring@error{haworth}{triose}{furanose}

% --------------------------------------------------------------------------
% Chair

%%%
% hexoses
% chain
\cbhdr@newchain\cbhdr@aldohexose@chair@chain#1#2#3#4{%
  -[:-10]
  ?(-[:150,.75]-[:90,.5,,1]\cbhdr@OH{6})!{cbhdr@chair@C5@OH#4}-[:10,,,,draw=none]
  -[:-50,,1,,draw=none](=_[:70]\cbhdr@anomer@O)
  \cbhdr@incr[:-170]!{cbhdr@chair@C2@OH#1}
  -[:-190,,,,\cbhdr@thick]!{cbhdr@chair@C3@OH#2}
  \cbhdr@decr[:130]?!{cbhdr@chair@C4@OH#3}
}

% pyranoses
\cbhdr@newring\cbhdr@aldohexose@chair@ring@pyranose#1#2#3#4#5{%
  -[:-10]
  ?(-[:150,.75]-[:90,.5,,1]\cbhdr@OH{6})-[:10]\cbhdr@ring@O
  -[:-50]!{cbhdr@chair@OH#1}
  \cbhdr@incr[:170]!{cbhdr@chair@C2@OH#2}
  -[:190,,,,\cbhdr@thick]!{cbhdr@chair@C3@OH#3}
  \cbhdr@decr[:130]?!{cbhdr@chair@C4@OH#4}
}

% furanoses
\newrobustcmd*\cbhdr@aldohexose@chair@ring@furanose{%
  \cbhdr@chair@error{furanose rings}%
}

%%%
% pentoses
\cbhdr@define@chair@errors{pentose}

%%%
% tetroses
\cbhdr@define@chair@errors{tetrose}

%%%
% trioses
\cbhdr@define@chair@errors{triose}


% ==========================================================================
% the user commands - built from the commands above using the already
% mentioned naming scheme
%
% <module>@<model>@<chain>/<ring>(@<ringtype>)

\newcommand*\cbhdr@model{}    % fischer/haworth/chair
\newcommand*\cbhdr@fischer{}  % @skeleton
\newcommand*\cbhdr@form{}     % chain/ring
\newcommand*\cbhdr@chain{chain}
\newcommand*\cbhdr@ring{ring@\cbhdr@ringtype}
\newcommand*\cbhdr@ringtype{} % pyranose/furanose
\newcommand*\cbhdr@ringtype@default{}

% --------------------------------------------------------------------------
% options for the user command:
\pgfkeys{
  cbhdr/.cd,
    model/.is choice ,
    model/fischer/.is choice ,
    model/fischer/skeleton/.code = \def\cbhdr@model{fischer@skeleton} ,
    model/fischer/full/.code     = \def\cbhdr@model{fischer} ,
    model/fischer/.default       = full ,
    model/haworth/.code          = \def\cbhdr@model{haworth} ,
    model/chair/.code            = \def\cbhdr@model{chair} ,
    chain/.code                  = \def\cbhdr@constitution{chain} ,
    ring/.is choice ,
    ring/true/.code              = \def\cbhdr@constitution{ring@\cbhdr@ringtype@default} ,
    ring/pyranose/.code          = \def\cbhdr@constitution{ring@pyranose} ,
    ring/furanose/.code          = \def\cbhdr@constitution{ring@furanose} ,
    ring/.default                = true ,
    anomer/.is choice ,
    anomer/alpha/.code           = \def\cbhdr@anomer{alpha} ,
    anomer/beta/.code            = \def\cbhdr@anomer{beta} ,
    anomer/undetermined/.code    = \def\cbhdr@anomer{undetermined} ,
    length/.is choice ,
    length/6/.code               =
      \def\cbhdr@ringtype@default{pyranose}
      \def\cbhdr@length{aldohexose} ,
    length/5/.code               =
      \def\cbhdr@ringtype@default{furanose}
      \def\cbhdr@length{aldopentose} ,
    length/4/.code               =
      \def\cbhdr@ringtype@default{furanose}
      \def\cbhdr@length{aldotetrose} ,
    length/3/.code               =
      % doesn't matter: will cause an error anyway
      \def\cbhdr@ringtype@default{pyranose}
      \def\cbhdr@length{aldotriose} ,
    hexose/.style                = { length=6 } ,
    pentose/.style               = { length=5 } ,
    tetrose/.style               = { length=4 } ,
    triose/.style                = { length=3 } ,
    3d/.is choice ,
    3d/true/.code                =
      \def\cbhdr@decr{>}
      \def\cbhdr@thick{line width=3pt}
      \def\cbhdr@incr{<} ,
    3d/false/.code               =
      \def\cbhdr@decr{-}
      \def\cbhdr@thick{}
      \def\cbhdr@incr{-} ,
    3d/.default                  = true ,
    defaults/.style              = {
      model  = fischer ,
      chain ,
      anomer = alpha ,
      length = 6
    } ,
    color/.code 2 args = \cbhdr@defcolor{#1}{#2}
}
\pgfqkeys{/cbhdr}{defaults}

% --------------------------------------------------------------------------
% the user command:
\newrobustcmd*\cbhdr@carbohydrate[2]{%
  \begingroup
    \pgfqkeys{/cbhdr}{defaults,#1}%
    \csuse{cbhdr@\cbhdr@length @\cbhdr@model @\cbhdr@constitution}{#2}%
  \endgroup
}

\newrobustcmd*\carbohydrate[2][]{\cbhdr@carbohydrate{#1}{#2}}

% ==========================================================================
% a command to define ready made carbohydrates

\newrobustcmd*\newaldose[1]{%
  \@ifnextchar[ % ]
    {\cbhdr@newaldose{#1}}
    {\cbhdr@newaldose{#1}[]}%
}

\protected\def\cbhdr@newaldose#1[#2]#3{%
  \cbhdr@expand@x
  \pgfkeys{
    cbhdr/.cd,
      \cbhdr@stripbs#1-defaults/.style={\unexpanded{#2}}
  }%
  \newrobustcmd*#1[1][]{%
    \expandafter\cbhdr@carbohydrate\expandafter{\cbhdr@stripbs#1-defaults,##1}{#3}%
  }%
}

\newrobustcmd*\renewaldose[1]{%
  \@ifnextchar[ % ]
    {\cbhdr@renewaldose{#1}}
    {\cbhdr@renewaldose{#1}[]}%
}

\protected\def\cbhdr@renewaldose#1[#2]#3{%
  \cbhdr@expand@x
  \pgfkeys{
    cbhdr/.cd,
      \cbhdr@stripbs#1-defaults/.style={\unexpanded{#2}}
  }%
  \renewrobustcmd*#1[1][]{%
    \expandafter\cbhdr@carbohydrate\expandafter{\cbhdr@stripbs#1-defaults,##1}{#3}%
  }%
}

% ==========================================================================
% predefined carbohydrates:
% aldohexoses:
\newaldose \allose   [hexose]{rrrr}
\newaldose \altrose  [hexose]{lrrr}
\newaldose \glucose  [hexose]{rlrr}
\newaldose \gulose   [hexose]{rrlr}
\newaldose \mannose  [hexose]{llrr}
\newaldose \idose    [hexose]{lrlr}
\newaldose \galactose[hexose]{rllr}
\newaldose \talose   [hexose]{lllr}

% aldopentoses:
\newaldose \ribose   [pentose]{rrr}
\newaldose \arabinose[pentose]{lrr}
\newaldose \xylose   [pentose]{rlr}
\newaldose \lyxose   [pentose]{llr}

\newaldose \desoxyribose[pentose]{0rr}

% aldotetroses:
\newaldose \erythrose[tetrose]{rr}
\newaldose \threose  [tetrose]{lr}

% aldotrioses:
\newaldose \glycerinaldehyde[triose]{r}

% ==========================================================================
% setup commands
% general defaults:
\newrobustcmd*\setcarbohydrates[1]{%
  \pgfkeys{
    cbhdr/.cd ,
      defaults/.style = {#1} ,
      defaults
  }%
}

% defaults for particular carbohydrate defined with \newaldose:
\newrobustcmd*\setcarbohydratedefaults[2]{%
  \edef\cbhdr@tmpa{\cbhdr@stripbs#1}%
  \pgfkeys{
    cbhdr/.cd ,
      \cbhdr@tmpa-defaults/.style = { #2 } ,
      \cbhdr@tmpa-defaults
  }%
}

\endinput
% ==========================================================================
% HISTORY:

% ==========================================================================
% TODO:
- Ringe fuer L-Saccharide
- Ketten für Tri- Tetr- und Pentosen
- Optionen für Farben

- Ketosen - viell. nur Fructose

- Optionen für oxidierte u reduzierte Formen?