moved cases post-processing under mk_partial_rules_mutual, using existing bookkeeping information;
normalized whitespace and indentation

--- a/src/HOL/Tools/Function/mutual.ML	Sun Sep 08 23:58:52 2013 +0200
+++ b/src/HOL/Tools/Function/mutual.ML	Mon Sep 09 00:14:07 2013 +0200
@@ -248,10 +248,39 @@
     fst (fold_map (project induct_inst) parts 0)
   end
 
-fun mk_partial_rules_mutual lthy inner_cont (m as Mutual {parts, fqgars, ...}) proof =
+fun mutual_cases_rule ctxt cases_rule n ST (MutualPart {i, cargTs, ...}) =
+  let
+    val arg_vars = 
+      cargTs
+      |> map_index (fn (i, T) => Free ("x" ^ string_of_int i, T)) (* FIXME: proper context *)
+
+    val argsT = fastype_of (HOLogic.mk_tuple arg_vars)
+    val args = Free ("x", argsT) (* FIXME: proper context *)
+
+    val cert = cterm_of (Proof_Context.theory_of ctxt)
+
+    val sumtree_inj = SumTree.mk_inj ST n i args
+
+    val sum_elims =
+      @{thms HOL.notE[OF Sum_Type.sum.distinct(1)] HOL.notE[OF Sum_Type.sum.distinct(2)]}
+
+    fun prep_subgoal i =
+      REPEAT (eresolve_tac @{thms Pair_inject Inl_inject[elim_format] Inr_inject[elim_format]} i)
+      THEN REPEAT (Tactic.eresolve_tac sum_elims i)
+  in
+    cases_rule
+    |> Thm.forall_elim @{cterm "P::bool"}
+    |> Thm.forall_elim (cert sumtree_inj)
+    |> Tactic.rule_by_tactic ctxt (ALLGOALS prep_subgoal)
+    |> Thm.forall_intr (cert args)
+    |> Thm.forall_intr @{cterm "P::bool"}
+  end
+
+
+fun mk_partial_rules_mutual lthy inner_cont (m as Mutual {parts, fqgars, n, ST, ...}) proof =
   let
     val result = inner_cont proof
-    val FunctionResult {G, R, cases, psimps, simple_pinducts=[simple_pinduct],
+    val FunctionResult {G, R, cases=[cases_rule], psimps, simple_pinducts=[simple_pinduct],
       termination, domintros, dom, pelims, ...} = result
 
     val (all_f_defs, fs) =
@@ -269,69 +298,18 @@
     val rew_simpset = put_simpset HOL_basic_ss lthy addsimps all_f_defs
     val mpsimps = map2 mk_mpsimp fqgars psimps
     val minducts = mutual_induct_rules lthy simple_pinduct all_f_defs m
+    val mcases = map (mutual_cases_rule lthy cases_rule n ST) parts
     val mtermination = full_simplify rew_simpset termination
     val mdomintros = Option.map (map (full_simplify rew_simpset)) domintros
 
   in
     FunctionResult { fs=fs, G=G, R=R, dom=dom,
       psimps=mpsimps, simple_pinducts=minducts,
-      cases=cases, pelims=pelims, termination=mtermination,
+      cases=mcases, pelims=pelims, termination=mtermination,
       domintros=mdomintros}
   end
 
 
-fun postprocess_cases_rules ctxt cont proof =
-  let val result = cont proof;
-      val FunctionResult {fs, G, R, dom, psimps, simple_pinducts, cases, pelims,
-                        termination, domintros, ...} = result;
-      val n_fs = length fs;
-      val domT = R |> dest_Free |> snd |> hd o snd o dest_Type
-
-      fun postprocess_cases_rule (idx,f) =
-        let val lhs_of =
-              prop_of #> Logic.strip_assums_concl #> HOLogic.dest_Trueprop #> HOLogic.dest_eq #> fst
-
-            val f_simps = filter (fn r => Term.head_of (lhs_of r) aconv f) psimps
-            val arity = length (snd (strip_comb (lhs_of (hd f_simps))))
-
-            val arg_vars = 
-                take arity (binder_types (fastype_of f))
-                |> map_index (fn (i, T) => Free ("x" ^ string_of_int i, T)) (* FIXME: proper context *)
-
-            val argsT = fastype_of (HOLogic.mk_tuple arg_vars);
-            val args = Free ("x", argsT); (* FIXME: proper context *)
-
-            val cert = cterm_of (Proof_Context.theory_of ctxt);
-
-            val sumtree_inj = SumTree.mk_inj domT n_fs (idx+1) args;
-
-            val sum_elims = @{thms HOL.notE[OF Sum_Type.sum.distinct(1)]
-                                   HOL.notE[OF Sum_Type.sum.distinct(2)]};
-            fun prep_subgoal i =
-              REPEAT (eresolve_tac @{thms Pair_inject Inl_inject[elim_format]
-                                          Inr_inject[elim_format]} i)
-              THEN REPEAT (Tactic.eresolve_tac sum_elims i);
-
-        in
-            hd cases
-              |> Thm.forall_elim @{cterm "P::bool"}
-              |> Thm.forall_elim (cert sumtree_inj)
-              |> Tactic.rule_by_tactic ctxt (ALLGOALS prep_subgoal)
-              |> Thm.forall_intr (cert args)
-              |> Thm.forall_intr @{cterm "P::bool"}
-
-        end;
-
-  val cases' = map_index postprocess_cases_rule fs;
-
-in
-  FunctionResult {fs=fs, G=G, R=R, dom=dom, psimps=psimps,
-                  simple_pinducts=simple_pinducts,
-                  cases=cases', pelims=pelims, termination=termination,
-                  domintros=domintros}
-end;
-
-
 fun prepare_function_mutual config defname fixes eqss lthy =
   let
     val mutual as Mutual {fsum_var=(n, T), qglrs, ...} =
@@ -343,9 +321,8 @@
     val (mutual', lthy'') = define_projections fixes mutual fsum lthy'
 
     val cont' = mk_partial_rules_mutual lthy'' cont mutual'
-    val cont'' = postprocess_cases_rules lthy'' cont'
   in
-    ((goalstate, cont''), lthy'')
+    ((goalstate, cont'), lthy'')
   end
 
 end