\documentclass[10pt]{article}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage[dvips,matrix,arrow,curve]{xy}
\usepackage{epsfig}
\usepackage{makeidx}

\setlength{\topmargin}{-0.25in}
\setlength{\oddsidemargin}{0.5in}
\setlength{\evensidemargin}{0in}
\setlength{\textwidth}{6in}
\setlength{\textheight}{9in}

\newcommand{\idf}[1]{{#1}}
\newcommand{\vb}[1]{{\it #1}}
\newcommand{\kw}[1]{{\bf #1}}
\newcommand{\sy}[1]{{\sffamily #1}}
\newcommand{\ty}[1]{{\tt #1}}
\newcommand{\hs}[1]{\hspace*{#1}}
\newcommand{\TeXScm}{\TeX$\leftarrow${\tt Scm}}
\newcommand{\rsrs}{R${}^7$RS}  % \r7rs is bad, s for 7

\newcommand{\bsl}{$\pmb{\backslash}$}
\newcommand{\ech}[1]{$\pmb{\backslash}${\tt #1}}
\newcommand{\chn}[1]{${}^{\#}\backslash${\tt #1}}

% \tba is a little vertical bar to mark the end of a TeX-tab
\newsavebox{\tba}
\savebox{\tba}[0pt]{\rule{0.3pt}{4pt}}
\newcommand{\tb}{\>\usebox{\tba}}

% it's more difficult than you might think to print the time of day
% I don't know why this comes out smaller than the date
\def\timeoday{{\count21=\time\count22=\time
  \divide\count21 by 60
  \number\count21 \multiply\count21 by 60 \advance \count22 by -\count21
  :\ifnum \count22<10 0\fi\number\count22}}
\newsavebox{\timeobox}
\savebox{\timeobox}{\timeoday}
\newcommand{\timeofday}{\usebox{\timeobox}}

\newsavebox{\lng}
\savebox{\lng}{$\langle$}
\newsavebox{\rng}
\savebox{\rng}{$\rangle$}

\newsavebox{\figbox}
\savebox{\figbox}[1in][c]{%
  \raisebox{-3mm}{\epsfig{file=cc-copyleft-88x31.eps, height=0.25in}}}

% This macro allows to enclose something in angle brackets by
% by writing \<something>.  I used that and liked it until I
% discovered that in a tabbing environment it is a backward tab.
% That is why it must be repeated at the begin of an indented comment.
% The inner definition needs double ## to get through the
% first level of macro expansion and will be canceled outside {...}.
%   [?] Knuth, The TeXbook, p.203
%
% ;;; See 230106 in test-doc.scm
%

\def\<#1>{\usebox{\lng}{#1}\usebox{\rng}}

\setlength{\topsep}{0mm}
\newenvironment{scheme}%
{\begin{tabbing}\setlength{\parindent}{0mm}}%
{\end{tabbing}}

\newenvironment{cmnt}%
               {\begin{minipage}{10cm}\ \\
                \def\<##1>{\usebox{\lng}{##1}\usebox{\rng}}
               }%
{\end{minipage}}
\newenvironment{cmntn}[1]%
               {\begin{minipage}{#1}\ \\
                \def\<##1>{\usebox{\lng}{##1}\usebox{\rng}}
               }%
{\end{minipage}}
\pagestyle{myheadings}\markright{\today}

%\makeindex