src/HOL/ex/SAT_Examples.thy

       val prop_fm = SAT_Solver.read_dimacs_cnf_file (Path.explode dimacsfile)
       fun and_to_list (Prop_Logic.And (fm1, fm2)) acc = and_to_list fm2 (fm1 :: acc)
         | and_to_list fm acc = rev (fm :: acc)
       val clauses = and_to_list prop_fm []
       val terms = map (HOLogic.mk_Trueprop o Prop_Logic.term_of_prop_formula) clauses
-      val cterms = map (Thm.cterm_of @{context}) terms
+      val cterms = map (Thm.cterm_of \<^context>) terms
       val start = Timing.start ()
-      val _ = SAT.rawsat_thm @{context} cterms
+      val _ = SAT.rawsat_thm \<^context> cterms
     in
       (Timing.result start, ! SAT.counter)
     end;
 \<close>