% \begin{meta-comment}
%
-% $Id: mdwmath.dtx,v 1.2 2003/09/05 16:14:36 mdw Exp $
+% mdwmath.dtx
%
% Various nicer mathematical things
%
%<+oldeqnarray> [1996/04/11 1.1 Old enhanced eqnarray]
% \end{meta-comment}
%
-% \CheckSum{729}
+% \CheckSum{740}
%% \CharacterTable
%% {Upper-case \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
%% Lower-case \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
% This also sets |\qedsymbol| if it's not set already.
% \qed
%
+% \subsection{Punctuation in displays}
+%
+% It's conventional to follow displayed equations with the necessary
+% punctuation for them to fit into the surrounding prose. This isn't
+% universal: Ian Stewart says in the preface to the third edition of his
+% \emph{Galois Theory}:\footnote{^^A
+% Chapman \& Hall/CRC Mathematics, 2004; ISBN 1-58488-393-6.} ^^A
+% \begin{quote}
+% Along the way I made once change that may raise a few eyebrows. I have
+% spent much of my career telling students that written mathematics should
+% have punctuation as well as symbols. If a symbol or a formula would be
+% followed by a comma if it were replaced by a word or phrase, then it
+% should be followed by a comma; however strange the formula then looks.
+%
+% I still think that punctuation is essential for formulas in the main body
+% of the text. If the formula is $t^2 + 1$, say, then it should have its
+% terminating comma. But I have come to the conclusion that eliminating
+% visual junk from the printed page is more important than punctuatory
+% pedantry, so that when the same formula is \emph{displayed}, for example
+% \[ t^2 + 1 \]
+% then it looks silly if the comma is included, like this,
+% \[ t^2 + 1 \mpunct{,} \]
+% and everything is much cleaner and less ambiguous without punctuation.
+%
+% Purists will hate this, though many of them would not have noticed had I
+% not pointed it out here. Until recently, I would have agreed. But I
+% think it is time we accepted that the act of displaying a formula equips
+% it with \emph{implicit} (invisible) punctuation. This is the 21st
+% century, and typography has moved on.
+% \end{quote}%
+%
+% \DescribeMacro\mpunct
+% I tended to agree with Prof.\ Stewart, even before I read his preface; but
+% now I'm not so sure, and it's clear that we're in the minority. Therefore,
+% the command |\mpunct| sets its argument as text, a little distance from
+% the preceding mathematics.
+%
% \begin{ignore}
% There used to be an eqnarray here, but that's migrated its way into the
% \package{mdwtab} package. Maybe the original version, without dependency
% The types provided (and it's easy-ish to add more) are:
%
% \def\ch{\char`}
-% \begin{description} \def\makelabel{\hskip\labelsep\normalfont\ttfamily}
+% \begin{description} \setdescriptionlabel{\normalfont\ttfamily#1}
% \item [r] Right aligned equation
% \item [c] Centre-aligned equation
% \item [l] Left aligned equation
% \end{macro}
% \end{macro}
%
+% \subsection{Punctuation in displays}
+%
+% \begin{macro}{\mpunct}
+%
+% This is actually a little more subtle than you'd expect. If the
+% \package{amstext} package is loaded, or something else has defined the
+% |\text| command, then we should use that; otherwise, just drop a box in and
+% hope for the best.
+%
+% \begin{macrocode}
+\def\mpunct#1{%
+ \,%
+ \ifx\text\@@undefined\hbox%
+ \else\expandafter\text\fi%
+ {#1}%
+}
+% \end{macrocode}
+%
+%\end{macro}
+%
% \begin{ignore}
% The following is the original definition of the enhanced eqnarray
% environment. It's not supported, although if you can figure out how to
~mdw / mdwtools / blobdiff