--- a/src/FOL/ex/If.thy Thu Dec 31 21:46:31 2015 +0100
+++ b/src/FOL/ex/If.thy Fri Jan 01 10:49:00 2016 +0100
@@ -26,7 +26,7 @@
apply (rule ifI)
oops
-text\<open>Trying again from the beginning in order to use @{text blast}\<close>
+text\<open>Trying again from the beginning in order to use \<open>blast\<close>\<close>
declare ifI [intro!]
declare ifE [elim!]
@@ -45,7 +45,7 @@
text \<open>An invalid formula. High-level rules permit a simpler diagnosis.\<close>
lemma "if(if(P,Q,R), A, B) \<longleftrightarrow> if(P, if(Q,A,B), if(R,B,A))"
apply auto
- -- \<open>The next step will fail unless subgoals remain\<close>
+ \<comment> \<open>The next step will fail unless subgoals remain\<close>
apply (tactic all_tac)
oops
@@ -53,7 +53,7 @@
lemma "if(if(P,Q,R), A, B) \<longleftrightarrow> if(P, if(Q,A,B), if(R,B,A))"
unfolding if_def
apply auto
- -- \<open>The next step will fail unless subgoals remain\<close>
+ \<comment> \<open>The next step will fail unless subgoals remain\<close>
apply (tactic all_tac)
oops