doc-src/TutorialI/Rules/find2.thy

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc-src/TutorialI/Rules/find2.thy	Thu Jun 23 07:32:59 2005 +0200
@@ -0,0 +1,43 @@
+(*<*)
+theory find2 imports Main begin
+lemma "A \<and> B"
+(*>*)
+
+txt{*\index{finding theorems}\index{searching theorems} In
+\S\ref{sec:find} we introduced Proof General's \pgmenu{Find} button
+for finding theorems in the database via pattern matching. If we are
+inside a proof we can be more specific and search for introduction,
+elimination and destruction rules \emph{w.r.t.\ the current goal}.
+For this purpose \pgmenu{Find} provides 3 aditional search criteria:
+\texttt{intro}, \texttt{elim} and \texttt{dest}.
+
+For example, given the goal @{subgoals[display,indent=0,margin=65]}
+when you click on \pgmenu{Find} and type in the search expression
+\texttt{intro} you are shown a few rules ending in @{text"\<Longrightarrow> ?P \<and> ?Q"},
+among them @{thm[source]conjI}. This can be very effective for finding
+if the very theorem you are trying to prove is already in the
+database: given the goal *}
+(*<*)
+oops
+lemma "A \<longrightarrow> A"
+(*>*)
+txt{*\vspace{-\bigskipamount}
+@{subgoals[display,indent=0,margin=65]}
+the search for \texttt{intro} finds not just @{thm[source] impI}
+but also @{thm[source] imp_refl}: @{thm imp_refl}.
+
+As before, search criteria can be combined freely: for example,
+\begin{ttbox}
+"_ \at\ _"  intro
+\end{ttbox}
+searches for all introduction rules that match the current goal and
+contain the @{text"@"} function.
+
+Searching for elimination and destruction rules via \texttt{elim} and
+\texttt{dest} is analogous to \texttt{intro} but takes the assumptions
+into account, too.
+*}
+(*<*)
+oops
+end
+(*>*)