Typesetting Go Diagrams with sgf2dg

Question

This is a question about typesetting diagrams for the Game of Go using the sgf2dg tools (currently in their version 4.252 available at their CPAN home). The sgf2dg tools can be used to create go diagrams from sgf files (smart game format) and to annotate the diagrams as in this example:

The diagrams look very nice to me and I would like to add comments with numbered stones as well. The sgf2dg TeX library gooemacs.sty makes available the command \textstone{} for exactly that purpose. The lines

This is a black stone: \textstone{\goo\003@}
This is a smaller black stone: {\setGoFonts at 1.8ex \textstone{\goo\003@}}

produce the nice output of:

Now my problem

The \textstone{} command does everything I want for a price: The input of the go stone's label has to be in that specific \goo (or \goe) format as a four digit code. In the example above \goo\003@ will produce a black stone labeled 3. \goo (and their relatives \goe, \bgoo and \bgoe) are font selection mechanisms. Here is the definition of \goo from the package gooemacs.sty:

\def\goo{\offinterlineskip\parindent=0pt\parskip=0pt\obeylines%black odd, white even
\setbox0\hbox{\gooegb +}\global\goIntWd=\wd0\global\goIntHt=\ht0\global\goTextAdj=2pt%
\def\0##1##2##3{\if##1?\gooegb ##3 \else \gooa\char##1##2 \fi}%
\def\1##1##2##3{\if##1?\gooegb ##3 \else \goob\char##1##2 \fi}%
\def\2##1##2##3{\if##1?\gooegb ##3 \else \gooc\char##1##2 \fi}%
\def\3##1##2##3{\if##1?\gooegb ##3 \else \good\char##1##2 \fi}%
\def\4##1##2##3{\if##1?\gooegb ##3 \else \gobl\char##1##2 \fi}%
\def\5##1##2##3{\if##1?\gooegb ##3 \else \gowl\char##1##2 \fi}%
\def\-##1##2{\gooegb ##1}%
\def\!##1{\leavevmode\hbox to \goIntWd{\hss\raise\goTextAdj\hbox{\rm ##1}\hss}}% #1 on empty intersections
}

I do, however, consider their encryption as too complicated to think about while writing my go diagram's annotation.

For annotating the diagrams I want to use a high (higher) level LaTeX macro like \Black{}. I want to write \Black{3} in my source code and then have it transformed to its corresponding \goo\003@.

Question

My attempt was to define a new command like:

\newcommand{\Black}[1]{%
\ifnum #1 >299 {\goo\#1@}\fi%
}
\Black{301}

but the replacement #1 fails (because of the preceding \ I guess) and produces the output \#1. How can I prevent that? How can I have TeX replace #1 and put it right after a backslash?

Remarks

I do realize there are more problems to solve: font selection based on even/odd label number, missing leading zeros with smaller stone numbers (1-99).

If you try to convert an sgf file to tex be aware of a bug in sgf2dg's version 4.252: stackoverflow.com.

The change of font size command in gooemacs.sty (\setGoFonts at #1) is missing end-of-line-%s, see What is the use of percent signs (%) at the end of lines?.

---

As a MWE I attach some working TeX code with the sgf2dg package. As mentioned above my attempt at \Black{} failed and is not included here. The example requires the installation of sgf2dg package (with gooemacs), which is also available on many Linux distributions.

\documentclass[margin=1mm]{standalone}
\usepackage{gooemacs}

\begin{document}
This is a black stone: \textstone{\goo\003@}
This is a smaller black stone: {\setGoFonts at 1.8ex \textstone{\goo\003@}}
\end{document}

Answer 1

If I understand the requirements I think

\Black{3}

\Black{41}

\Black{99}

\Black{555}

produces

testing:\goo\003@
testing:\goo\041@
testing:\goo\099@
testing:\goo\555@

In this version just echoed to the terminal, remove the \goo definition for your real code.

\documentclass{article}

%this line just for testing without the go package
\def\goo#1@{\typeout{testing:\string\goo\string#1@}}

\newcommand\Black[1]{{%
\count0=#1\relax
\divide\count0 by 100\relax
\count2=\numexpr#1-100*\count0\relax
\count4=\count2\relax
\divide\count2 by 10
\count4=\numexpr\count4-10*\count2\relax
\edef\tmp{\noexpand\goo
\expandafter\noexpand\csname\the\count0\endcsname
\the\count2
\the\count4
@}\tmp
}}
\begin{document}


\Black{3}

\Black{41}

\Black{99}

\Black{555}


\end{document}

Answer 2

In this answer I present a solution that works for even numbered stones as well as for letter markings. Instead of writing a high level macro for \goo we replace it by a new font selection mechanism \mygo.

\documentclass[margin=3mm]{standalone}
\usepackage{gooemacs}

\def\mygo{%
  \def\a##1##2##3{\ifodd ##3 \gooa\char##2##3 \else \goea\char##2##3\fi}% 1 - 99
  \def\b##1##2##3{\ifodd ##3 \goob\char##2##3 \else \goeb\char##2##3\fi}% hundreds
  \def\c##1##2##3{\ifodd ##3 \gooc\char##2##3 \else \goec\char##2##3\fi}% two hundreds
  \def\d##1##2##3{\ifodd ##3 \good\char##2##3 \else \goed\char##2##3\fi}% three hundreds
  \def\s##1{\gooegb##1}%
  \def\t##1##2{\gobl\char##1##2}% if label, subst 2 for ##1 ??
}

\newcommand{\Black}[1]{%
\if!\ifnum9<1#1!\fi% if it's a number:
{\ifnum #1<10 {\mygo\a00#1}%
  \else \ifnum #1<100 {\mygo\a0#1}%
  \else \ifnum #1<200 {\mygo\b#1}%
  \else \ifnum #1<300 {\mygo\c#1}%
  \else \ifnum #1<400 {\mygo\d#1}%
  \fi% larger numbers will not be printed, no error message.
  \fi%
  \fi%
  \fi%
  \fi}%
\else%if it's a letter:
{\mygo\t\numexpr`#1-`\a+1\relax}\fi%
}%

\begin{document}
\begin{minipage}{5cm}

\Black{1}\Black{2}\Black{11}\Black{12}\Black{111}\Black{112}\Black{211}\Black{212}\Black{311}\Black{312}\\
\Black{a}\Black{b}\Black{c}\Black{d}\Black{e}\Black{f}\Black{g}\Black{h}\Black{i}\Black{j}

\end{minipage}
\end{document}

The solution can easily be extended for White stones.

---

Possible extensions/improvements: I wonder if the number of conditionals can be reduced. The order of the if-then-else structure might better test for letters first, as one is more likely to comment on Black a than on Black 312?

Also, symbols are not supported yet. I wonder if optional arguments are the way to go here. For example like \Black[t]{} for a Black stone marked with a triangle. The definition of \mygo is prepared for this with \def\s##1{\gooegb##1}% (\gooegb is sgf2dg font of marked stones).