# HG changeset patch
# User wenzelm
# Date 1325879332 -3600
# Node ID cc374091999bd9548b44281e7fce60dd86bf2582
# Parent  c932c80d3eaeb38294dbdbd1fe93b4b7ea422365# Parent  463b594e186acae43d0c240d5637028123836561
merged

diff -r c932c80d3eae -r cc374091999b src/HOL/Tools/Datatype/datatype_case.ML
--- a/src/HOL/Tools/Datatype/datatype_case.ML	Fri Jan 06 20:39:50 2012 +0100
+++ b/src/HOL/Tools/Datatype/datatype_case.ML	Fri Jan 06 20:48:52 2012 +0100
@@ -59,17 +59,17 @@
 fun add_row_used ((prfx, pats), (tm, tag)) =
   fold Term.add_free_names (tm :: pats @ map Free prfx);
 
-(*try to preserve names given by user*)
-fun default_names names ts =
-  map (fn ("", Free (name', _)) => name' | (name, _) => name) (names ~~ ts);
+fun default_name name (t, cs) =
+  let
+    val name' = if name = "" then (case t of Free (name', _) => name' | _ => name) else name;
+    val cs' = if is_Free t then cs else filter_out Term_Position.is_position cs;
+  in (name, cs') end;
 
 fun strip_constraints (Const (@{syntax_const "_constrain"}, _) $ t $ tT) =
       strip_constraints t ||> cons tT
   | strip_constraints t = (t, []);
 
-val recover_constraints =
-  fold (fn tT => fn t => Syntax.const @{syntax_const "_constrain"} $ t $ tT);
-
+fun constrain tT t = Syntax.const @{syntax_const "_constrain"} $ t $ tT;
 fun constrain_Abs tT t = Syntax.const @{syntax_const "_constrainAbs"} $ t $ tT;
 
 
@@ -90,7 +90,7 @@
 fun strip_comb_positions tm =
   let
     fun result t ts = (Term_Position.strip_positions t, ts);
-    fun strip (t as (Const (@{syntax_const "_constrain"}, _) $ _ $ _)) ts = result t ts
+    fun strip (t as Const (@{syntax_const "_constrain"}, _) $ _ $ _) ts = result t ts
       | strip (f $ t) ts = strip f (t :: ts)
       | strip t ts = result t ts;
   in strip tm [] end;
@@ -105,11 +105,15 @@
           (Const (name', _), args) =>
             if name = name' then
               if length args = k then
-                let val (args', cnstrts') = split_list (map strip_constraints args) in
+                let
+                  val constraints' = map strip_constraints args;
+                  val (args', cnstrts') = split_list constraints';
+                  val (names', cnstrts'') = split_list (map2 default_name names constraints');
+                in
                   ((((prfx, args' @ ps), rhs) :: in_group, not_in_group),
-                   (default_names names args', map2 append cnstrts cnstrts'))
+                   (names', map2 append cnstrts cnstrts''))
                 end
-              else raise CASE_ERROR ("Wrong number of arguments for constructor " ^ name, i)
+              else raise CASE_ERROR ("Wrong number of arguments for constructor " ^ quote name, i)
             else ((in_group, row :: not_in_group), (names, cnstrts))
         | _ => raise CASE_ERROR ("Not a constructor pattern", i)))
     rows (([], []), (replicate k "", replicate k [])) |>> pairself rev
@@ -142,7 +146,7 @@
                       [((prfx, gvars @ map Free (xs ~~ Ts)),
                         (Const (@{const_syntax undefined}, res_ty), ~1))]
                     end
-                  else in_group
+                  else in_group;
               in
                 {constructor = c',
                  new_formals = gvars,
@@ -162,14 +166,14 @@
   let
     val get_info = Datatype_Data.info_of_constr_permissive (Proof_Context.theory_of ctxt);
 
-    fun expand constructors used ty ((_, []), _) = raise CASE_ERROR ("mk_case: expand_var_row", ~1)
+    fun expand constructors used ty ((_, []), _) = raise CASE_ERROR ("mk_case: expand", ~1)
       | expand constructors used ty (row as ((prfx, p :: ps), (rhs, tag))) =
           if is_Free p then
             let
               val used' = add_row_used row used;
               fun expnd c =
                 let val capp = list_comb (fresh_constr ty_match ty_inst ty used' c)
-                in ((prfx, capp :: ps), (subst_free [(p, capp)] rhs, tag)) end
+                in ((prfx, capp :: ps), (subst_free [(p, capp)] rhs, tag)) end;
             in map expnd constructors end
           else [row];
 
@@ -189,7 +193,7 @@
                 in mk us rows' end
             | SOME (Const (cname, cT), i) =>
                 (case Option.map ty_info (get_info (cname, cT)) of
-                  NONE => raise CASE_ERROR ("Not a datatype constructor: " ^ cname, i)
+                  NONE => raise CASE_ERROR ("Not a datatype constructor: " ^ quote cname, i)
                 | SOME {case_name, constructors} =>
                     let
                       val pty = body_type cT;
@@ -312,7 +316,7 @@
       in
         make_case_untyped ctxt
           (if err then Error else Warning) []
-          (recover_constraints (filter_out Term_Position.is_position (flat cnstrts)) t)
+          (fold constrain (filter_out Term_Position.is_position (flat cnstrts)) t)
           cases
       end
   | case_tr _ _ _ = case_error "case_tr";