src/HOL/Corec_Examples/Stream_Processor.thy

 by(subst run.code; simp; fail)+
 
 lemma copy_sel[simp]: "out copy = Get (\<lambda>a. Put a copy)"
   by (subst copy.code; simp)
 
-corecursive sp_comp (infixl "oo" 65) where
+corecursive sp_comp (infixl \<open>oo\<close> 65) where
   "sp oo sp' = (case (out sp, out sp') of
       (Put b sp, _) \<Rightarrow> In (Put b (sp oo sp'))
     | (Get f, Put b sp) \<Rightarrow> In (f b) oo sp
     | (_, Get g) \<Rightarrow> get (\<lambda>a. (sp oo In (g a))))"
   by (relation "map_prod In In ` sub <*lex*> map_prod In In ` sub")