src/Doc/Tutorial/document/ctl0.tex

generate 'code' attribute only if 'code' plugin is enabled

\index{model checking example|(}%
\index{lfp@{\texttt{lfp}}!applications of|see{CTL}}
\input{Base.tex}
\input{PDL.tex}
\input{CTL.tex}
\index{model checking example|)}