% Subject:      exercise-macros
% author :      Alan R. Rogers
 
% These macros are modified versions of the \exercise and \answer macros
% on p. 422 of the TeXbook.  The modifications are to make them work under
% LaTeX.
% Usage:
%  \documentstyle [12pt,twoside]{report}
%  \input exercise
%  \begin{document}
%  \chapter{Text}
%  \exercise In what season of the year did George Washington spend the
%  winter in Valley forge?
%  \answer 1776
%
%  \exercise In what year did George Washington spend the winter there?
%  \answer Winter
%
%  \chapter{Answers}
%  \listanswers     % The answers are inserted here.
%  \end{document}
% BUG: The blank lines after the \answer macros are *mandatory*.  If you leave
% them out TeX will exhaust the file looking for them.
%  Alan R. Rogers (rogers@anthro.utah.edu), U. of Utah,  10/23/88
 
\newcounter{exno}[chapter]
 
%\newenvironment{exercise}{\begin{list}{\small\llap{$\bullet$\kern.15em}%
%    {\footnotesize EXERCISE \bf\thechapter.\theexno}}{
%    \usecounter{exno}\small
%	\setlength{\labelwidth}{5em} \setlength{\labelsep}{1em}
%	\setlength{\leftmargin}{6em}
%	\setlength{\itemsep}{0em} \setlength{\topsep}{\parsep}}}
%        {\end{list}\normalsize}
 
\outer\def\exercise{\addtocounter{exno}{1}
  \par\small\noindent\llap{$\bullet$\kern.15em}% bullet in margin
  {\footnotesize EXERCISE \bf\thechapter.\theexno}\par\nopagebreak\noindent}
 
\def\ansno#1.#2:{\par\noindent
  \hbox to\parindent{\bf\hss#1.#2.\enspace}\ignorespaces}
\chardef\other=12
\newwrite\ans
\immediate\openout\ans=answers
\outer\def\answer{\normalsize\par
  \immediate\write\ans{}
  \immediate\write\ans{\string\ansno\thechapter.\theexno:}
  \copytoblankline}
\def\copytoblankline{\begingroup\setupcopy\copyans}
\def\setupcopy{\def\do##1{\catcode`##1=\other}\dospecials
  \catcode`\|=\other \obeylines}
{\obeylines \gdef\copyans#1
  {\def\next{#1}%
  \ifx\next\empty\let\next=\endgroup %
  \else\immediate\write\ans{\next} \let\next=\copyans\fi\next}}
 
\def\listanswers{\immediate\closeout\ans\input answers}