diff -r 6e0f56764ff8 -r dc95a56b1953 ProgTutorial/document/root.tex
--- a/ProgTutorial/document/root.tex	Wed Apr 29 00:36:14 2009 +0200
+++ b/ProgTutorial/document/root.tex	Tue May 05 03:21:49 2009 +0200
@@ -107,6 +107,11 @@
 \renewcommand{\isatagsmall}{\begingroup\small}
 \renewcommand{\endisatagsmall}{\endgroup}
 
+% for code that should not be printed
+\isakeeptag{no}
+\renewcommand{\isatagno}{}
+\renewcommand{\endisatagno}{}
+
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \renewenvironment{isabelle}
 {\begin{trivlist}\begin{isabellebody}\small\item\relax}