doc-src/TutorialI/Misc/document/case_exprs.tex

 by \methdx{case_tac}.  Here is a trivial example:%
 \end{isamarkuptext}%
 \isamarkuptrue%
 \isacommand{lemma}\ {\isachardoublequote}{\isacharparenleft}case\ xs\ of\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymRightarrow}\ {\isacharbrackleft}{\isacharbrackright}\ {\isacharbar}\ y{\isacharhash}ys\ {\isasymRightarrow}\ xs{\isacharparenright}\ {\isacharequal}\ xs{\isachardoublequote}\isanewline
 \isamarkupfalse%
-\isacommand{apply}{\isacharparenleft}case{\isacharunderscore}tac\ xs{\isacharparenright}\isamarkupfalse%
-%
-\begin{isamarkuptxt}%
-\noindent
-results in the proof state
-\begin{isabelle}%
-\ {\isadigit{1}}{\isachardot}\ xs\ {\isacharequal}\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymLongrightarrow}\ {\isacharparenleft}case\ xs\ of\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymRightarrow}\ {\isacharbrackleft}{\isacharbrackright}\ {\isacharbar}\ y\ {\isacharhash}\ ys\ {\isasymRightarrow}\ xs{\isacharparenright}\ {\isacharequal}\ xs\isanewline
-\ {\isadigit{2}}{\isachardot}\ {\isasymAnd}a\ list{\isachardot}\isanewline
-\isaindent{\ {\isadigit{2}}{\isachardot}\ \ \ \ }xs\ {\isacharequal}\ a\ {\isacharhash}\ list\ {\isasymLongrightarrow}\ {\isacharparenleft}case\ xs\ of\ {\isacharbrackleft}{\isacharbrackright}\ {\isasymRightarrow}\ {\isacharbrackleft}{\isacharbrackright}\ {\isacharbar}\ y\ {\isacharhash}\ ys\ {\isasymRightarrow}\ xs{\isacharparenright}\ {\isacharequal}\ xs%
-\end{isabelle}
-which is solved automatically:%
-\end{isamarkuptxt}%
+\isamarkupfalse%
 \isamarkuptrue%
-\isacommand{apply}{\isacharparenleft}auto{\isacharparenright}\isamarkupfalse%
+\isamarkupfalse%
 \isamarkupfalse%
 %
 \begin{isamarkuptext}%
 Note that we do not need to give a lemma a name if we do not intend to refer
 to it explicitly in the future.