X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=mjo-proof_by_cases.tex;h=247d28049226213ae19173026680540fa94112c7;hb=a6c1d186ec5bbd8d02dfd2f057cd147afdfe900f;hp=f2d9b90987c8b894d74f8f38c41b16a620931029;hpb=d8b66e409213fa4d3392f654081eb8dd85f03c4c;p=mjotex.git

diff --git a/mjo-proof_by_cases.tex b/mjo-proof_by_cases.tex
index f2d9b90..247d280 100644
--- a/mjo-proof_by_cases.tex
+++ b/mjo-proof_by_cases.tex
@@ -8,9 +8,34 @@
 %
 % Case 2 (x < 0): derp.
 %
+\ifx\havemjoproofbycases\undefined
+\def\havemjoproofbycases{1}
 
-% Used below to define pcases.
-\usepackage{enumitem}
+
+% Used below to define pcases. The ``loadonly'' parameter prevents
+% a very bad interaction with the beamer document class.
+\usepackage[loadonly]{enumitem}
+
+% Needed to perform division in the definition of \singleblskip.
+\usepackage{calc}
+
+% A \baselineskip without the \baselinestretch scaling factor. Even
+% though \baselinestretch defaults to 1.0, it doesn't really have that
+% value. Thus to avoid division by zero, we need to do the ``is this
+% thing empty?'' hack.
+%
+% If we use \baselineskip instead of \singleblskip in our list, things
+% get real ugly when the text is e.g. double-spaced.
+%
+\newlength{\singleblskip}
+\setlength{\singleblskip}{
+  \baselineskip/\real{
+      \if\relax\detokenize{\baselinestretch}\relax
+        \baselinestretch%
+      \else
+        1%
+      \fi}
+}
 
 % Using the enumitem package, we define a new type of list, called
 % ``pcases'' (proof by cases). Each case has a label with an arabic
@@ -26,7 +51,7 @@
   leftmargin=0pt,
   listparindent=\parindent,
   parsep=\parskip,
-  itemsep=\baselineskip}
+  itemsep=\singleblskip}
 
 % The optional argument here gets stuffed into the \thiscase macro, to
 % be called by pcases when it creates this list item. The \hfill is a
@@ -35,5 +60,8 @@
 % so we consume the rest of the line instead.
 \newcommand{\case}[1][]{
   \def\thiscase{#1}%
-  \item \hfill\par\vspace{\baselineskip}
+  \item \hfill\par\vspace{\singleblskip}
 }
+
+
+\fi