Fix version-dependent SBEtests by introducing \SqVersionSwitch

Collections/Collections.tex

@@ -867,7 +867,7 @@ \subsection{Other messages}
 \paragraph{\mthind{Collection}{count:}} The message \ct{count:} returns the number of elements satisfying a condition.  The condition is represented as a boolean block.
 
 \begin{code}{@TEST}
-Smalltalk allClasses count: [:each | 'Collection*' match: each asString ] --> 4
+Smalltalk allClasses count: [:each | 'Collection*' match: each asString ] --> !\SqVersionSwitch{6.0}{4}{2}!
 \end{code}
 
 \paragraph{\mthind{Collection}{includes:}} The message \ct{includes:} checks whether the argument is contained in the collection. 

common.tex

@@ -543,9 +543,27 @@
 \setcounter{totalnumber}{20}
 \setcounter{dbltopnumber}{9}
 %=============================================================
-% apb doesn't like paragraphs to run in to each other without a break
+% apb doesn't like paragraphs to run into each other without a break
 \parskip 1ex
 %=============================================================
+\usepackage{pdftexcmds}
+\makeatletter
+\newcommand\compareStringsDo[4]{%
+	\lowercase{\ifcase\pdf@strcmp{#1}{#2}}%
+		#4\or
+		#4\else
+		#3\fi
+}
+\makeatother
+% Usage: \SqVersionSwitch{6.0}{We are Squeak 6.0 or later!}{We are before Squeak 6.0}
+\newcommand{\SqVersionSwitch}[3]{%
+	\ifdefined\SQUEAKVERSION%
+	\compareStringsDo{\SQUEAKVERSION}{#1}{#2}{#3}%
+	\else%
+	#1%
+	\fi%
+}
+%=============================================================
 %:Stuff to check, merge or deprecate
 %\setlength{\marginparsep}{2mm}
 %\renewcommand{\baselinestretch}{1.1}