abstract interfaces for type algebra;
authorwenzelm
Tue, 16 May 2006 13:01:28 +0200
changeset 19645 bbda28f2d379
parent 19644 0b01436e1843
child 19646 91c0ae7e542b
abstract interfaces for type algebra; tuned;
src/Pure/sorts.ML
--- a/src/Pure/sorts.ML	Tue May 16 13:01:27 2006 +0200
+++ b/src/Pure/sorts.ML	Tue May 16 13:01:28 2006 +0200
@@ -24,34 +24,36 @@
   val insert_typs: typ list -> sort list -> sort list
   val insert_term: term -> sort list -> sort list
   val insert_terms: term list -> sort list -> sort list
-  type classes
-  type arities
-  val class_eq: classes -> class * class -> bool
-  val class_less: classes -> class * class -> bool
-  val class_le: classes -> class * class -> bool
-  val sort_eq: classes -> sort * sort -> bool
-  val sort_le: classes -> sort * sort -> bool
-  val sorts_le: classes -> sort list * sort list -> bool
-  val inter_sort: classes -> sort * sort -> sort
-  val norm_sort: classes -> sort -> sort
-  val add_arities: Pretty.pp -> classes -> string * (class * sort list) list -> arities -> arities
-  val rebuild_arities: Pretty.pp -> classes -> arities -> arities
-  val merge_arities: Pretty.pp -> classes -> arities * arities -> arities
-  val add_class: Pretty.pp -> class * class list -> classes -> classes
-  val add_classrel: Pretty.pp -> class * class -> classes -> classes
-  val merge_classes: Pretty.pp -> classes * classes -> classes
+  type algebra
+  val rep_algebra: algebra ->
+   {classes: stamp Graph.T,
+    arities: (class * (class * sort list)) list Symtab.table}
+  val classes: algebra -> class list
+  val super_classes: algebra -> class -> class list
+  val class_less: algebra -> class * class -> bool
+  val class_le: algebra -> class * class -> bool
+  val sort_eq: algebra -> sort * sort -> bool
+  val sort_le: algebra -> sort * sort -> bool
+  val sorts_le: algebra -> sort list * sort list -> bool
+  val inter_sort: algebra -> sort * sort -> sort
+  val certify_class: algebra -> class -> class    (*exception TYPE*)
+  val certify_sort: algebra -> sort -> sort       (*exception TYPE*)
+  val add_class: Pretty.pp -> class * class list -> algebra -> algebra
+  val add_classrel: Pretty.pp -> class * class -> algebra -> algebra
+  val add_arities: Pretty.pp -> string * (class * sort list) list -> algebra -> algebra
+  val empty_algebra: algebra
+  val merge_algebra: Pretty.pp -> algebra * algebra -> algebra
   type class_error
   val class_error: Pretty.pp -> class_error -> 'a
   exception CLASS_ERROR of class_error
-  val mg_domain: classes * arities -> string -> sort -> sort list   (*exception CLASS_ERROR*)
-  val of_sort: classes * arities -> typ * sort -> bool
-  val of_sort_derivation: Pretty.pp -> classes * arities ->
+  val mg_domain: algebra -> string -> sort -> sort list   (*exception CLASS_ERROR*)
+  val of_sort: algebra -> typ * sort -> bool
+  val of_sort_derivation: Pretty.pp -> algebra ->
     {classrel: 'a * class -> class -> 'a,
      constructor: string -> ('a * class) list list -> class -> 'a,
      variable: typ -> ('a * class) list} ->
     typ * sort -> 'a list   (*exception CLASS_ERROR*)
-  val witness_sorts: classes * arities -> string list ->
-    sort list -> sort list -> (typ * sort) list
+  val witness_sorts: algebra -> string list -> sort list -> sort list -> (typ * sort) list
 end;
 
 structure Sorts: SORTS =
@@ -99,60 +101,84 @@
     c1 <= c2 holds Ss1 <= Ss2.
 *)
 
-type classes = stamp Graph.T;
-type arities = (class * (class * sort list)) list Symtab.table;
+datatype algebra = Algebra of
+ {classes: stamp Graph.T,
+  arities: (class * (class * sort list)) list Symtab.table};
+
+fun rep_algebra (Algebra args) = args;
+
+val classes_of = #classes o rep_algebra;
+val arities_of = #arities o rep_algebra;
+
+fun make_algebra (classes, arities) =
+  Algebra {classes = classes, arities = arities};
+
+fun map_classes f (Algebra {classes, arities}) = make_algebra (f classes, arities);
+fun map_arities f (Algebra {classes, arities}) = make_algebra (classes, f arities);
+
+
+(* classes *)
+
+val classes = Graph.keys o classes_of;
+val super_classes = Graph.imm_succs o classes_of;
 
 
 (* class relations *)
 
-fun class_eq (_: classes) (c1, c2:class) = c1 = c2;
-val class_less: classes -> class * class -> bool = Graph.is_edge;
-fun class_le classes (c1, c2) = c1 = c2 orelse class_less classes (c1, c2);
+val class_less = Graph.is_edge o classes_of;
+fun class_le algebra (c1, c2) = c1 = c2 orelse class_less algebra (c1, c2);
 
 
 (* sort relations *)
 
-fun sort_le classes (S1, S2) =
-  forall (fn c2 => exists (fn c1 => class_le classes (c1, c2)) S1) S2;
+fun sort_le algebra (S1, S2) =
+  forall (fn c2 => exists (fn c1 => class_le algebra (c1, c2)) S1) S2;
 
-fun sorts_le classes (Ss1, Ss2) =
-  ListPair.all (sort_le classes) (Ss1, Ss2);
+fun sorts_le algebra (Ss1, Ss2) =
+  ListPair.all (sort_le algebra) (Ss1, Ss2);
 
-fun sort_eq classes (S1, S2) =
-  sort_le classes (S1, S2) andalso sort_le classes (S2, S1);
+fun sort_eq algebra (S1, S2) =
+  sort_le algebra (S1, S2) andalso sort_le algebra (S2, S1);
 
 
 (* intersection *)
 
-fun inter_class classes c S =
+fun inter_class algebra c S =
   let
     fun intr [] = [c]
       | intr (S' as c' :: c's) =
-          if class_le classes (c', c) then S'
-          else if class_le classes (c, c') then intr c's
+          if class_le algebra (c', c) then S'
+          else if class_le algebra (c, c') then intr c's
           else c' :: intr c's
   in intr S end;
 
-fun inter_sort classes (S1, S2) =
-  sort_strings (fold (inter_class classes) S1 S2);
+fun inter_sort algebra (S1, S2) =
+  sort_strings (fold (inter_class algebra) S1 S2);
 
 
-(* normal forms *)
+(* normal form *)
 
 fun norm_sort _ [] = []
   | norm_sort _ (S as [_]) = S
-  | norm_sort classes S =
-      filter (fn c => not (exists (fn c' => class_less classes (c', c)) S)) S
+  | norm_sort algebra S =
+      filter (fn c => not (exists (fn c' => class_less algebra (c', c)) S)) S
       |> sort_distinct string_ord;
 
 
+(* certify *)
+
+fun certify_class algebra c =
+  if can (Graph.get_node (classes_of algebra)) c then c
+  else raise TYPE ("Undeclared class: " ^ quote c, [], []);
+
+fun certify_sort classes = norm_sort classes o map (certify_class classes);
+
+
 
 (** build algebras **)
 
 (* classes *)
 
-local
-
 fun err_dup_classes cs =
   error ("Duplicate declaration of class(es): " ^ commas_quote cs);
 
@@ -160,26 +186,13 @@
   error (cat_lines (map (fn cs =>
     "Cycle in class relation: " ^ Pretty.string_of_classrel pp cs) css));
 
-in
-
-fun add_class pp (c, cs) classes =
+fun add_class pp (c, cs) = map_classes (fn classes =>
   let
     val classes' = classes |> Graph.new_node (c, stamp ())
       handle Graph.DUP dup => err_dup_classes [dup];
     val classes'' = classes' |> fold Graph.add_edge_trans_acyclic (map (pair c) cs)
       handle Graph.CYCLES css => err_cyclic_classes pp css;
-  in classes'' end;
-
-fun add_classrel pp rel classes =
-  classes |> Graph.add_edge_trans_acyclic rel
-    handle Graph.CYCLES css => err_cyclic_classes pp css;
-
-fun merge_classes pp args : classes =
-  Graph.merge_trans_acyclic (op =) args
-    handle Graph.DUPS cs => err_dup_classes cs
-        | Graph.CYCLES css => err_cyclic_classes pp css;
-
-end;
+  in classes'' end);
 
 
 (* arities *)
@@ -195,12 +208,12 @@
     Pretty.string_of_arity pp (t, Ss, [c]) ^ " and\n  " ^
     Pretty.string_of_arity pp (t, Ss', [c']));
 
-fun coregular pp C t (c, (c0, Ss)) ars =
+fun coregular pp algebra t (c, (c0, Ss)) ars =
   let
     fun conflict (c', (_, Ss')) =
-      if class_le C (c, c') andalso not (sorts_le C (Ss, Ss')) then
+      if class_le algebra (c, c') andalso not (sorts_le algebra (Ss, Ss')) then
         SOME ((c, c'), (c', Ss'))
-      else if class_le C (c', c) andalso not (sorts_le C (Ss', Ss)) then
+      else if class_le algebra (c', c) andalso not (sorts_le algebra (Ss', Ss)) then
         SOME ((c', c), (c', Ss'))
       else NONE;
   in
@@ -209,41 +222,63 @@
     | NONE => (c, (c0, Ss)) :: ars)
   end;
 
-fun insert pp C t (c, (c0, Ss)) ars =
+fun complete algebra (c0, Ss) = map (rpair (c0, Ss)) (c0 :: super_classes algebra c0);
+
+fun insert pp algebra t (c, (c0, Ss)) ars =
   (case AList.lookup (op =) ars c of
-    NONE => coregular pp C t (c, (c0, Ss)) ars
+    NONE => coregular pp algebra t (c, (c0, Ss)) ars
   | SOME (_, Ss') =>
-      if sorts_le C (Ss, Ss') then ars
-      else if sorts_le C (Ss', Ss) then
-        coregular pp C t (c, (c0, Ss))
+      if sorts_le algebra (Ss, Ss') then ars
+      else if sorts_le algebra (Ss', Ss) then
+        coregular pp algebra t (c, (c0, Ss))
           (filter_out (fn (c'', (_, Ss'')) => c = c'' andalso Ss'' = Ss') ars)
       else err_conflict pp t NONE (c, Ss) (c, Ss'));
 
-fun complete C (c0, Ss) = map (rpair (c0, Ss)) (Graph.all_succs C [c0]);
+fun insert_ars pp algebra (t, ars) arities =
+  let val ars' =
+    Symtab.lookup_list arities t
+    |> fold_rev (fold_rev (insert pp algebra t)) (map (complete algebra) ars)
+  in Symtab.update (t, ars') arities end;
 
 in
 
-fun add_arities pp classes (t, ars) arities =
-  let val ars' =
-    Symtab.lookup_list arities t
-    |> fold_rev (fold_rev (insert pp classes t)) (map (complete classes) ars)
-  in Symtab.update (t, ars') arities end;
-
-fun add_arities_table pp classes =
-  Symtab.fold (fn (t, ars) => add_arities pp classes (t, map snd ars));
+fun add_arities pp arg algebra = algebra |> map_arities (insert_ars pp algebra arg);
 
-fun rebuild_arities pp classes arities =
-  Symtab.empty
-  |> add_arities_table pp classes arities;
-
-fun merge_arities pp classes (arities1, arities2) =
-  Symtab.empty
-  |> add_arities_table pp classes arities1
-  |> add_arities_table pp classes arities2;
+fun add_arities_table pp algebra =
+  Symtab.fold (fn (t, ars) => insert_ars pp algebra (t, map snd ars));
 
 end;
 
 
+(* classrel *)
+
+fun rebuild_arities pp algebra = algebra |> map_arities (fn arities =>
+  Symtab.empty
+  |> add_arities_table pp algebra arities);
+
+fun add_classrel pp rel = rebuild_arities pp o map_classes (fn classes =>
+  classes |> Graph.add_edge_trans_acyclic rel
+    handle Graph.CYCLES css => err_cyclic_classes pp css);
+
+
+(* empty and merge *)
+
+val empty_algebra = make_algebra (Graph.empty, Symtab.empty);
+
+fun merge_algebra pp
+   (Algebra {classes = classes1, arities = arities1},
+    Algebra {classes = classes2, arities = arities2}) =
+  let
+    val classes' = Graph.merge_trans_acyclic (op =) (classes1, classes2)
+      handle Graph.DUPS cs => err_dup_classes cs
+          | Graph.CYCLES css => err_cyclic_classes pp css;
+    val algebra0 = make_algebra (classes', Symtab.empty);
+    val arities' = Symtab.empty
+      |> add_arities_table pp algebra0 arities1
+      |> add_arities_table pp algebra0 arities2;
+  in make_algebra (classes', arities') end;
+
+
 
 (** sorts of types **)
 
@@ -261,13 +296,14 @@
 
 (* mg_domain *)
 
-fun mg_domain (classes, arities) a S =
+fun mg_domain algebra a S =
   let
+    val arities = arities_of algebra;
     fun dom c =
       (case AList.lookup (op =) (Symtab.lookup_list arities a) c of
         NONE => raise CLASS_ERROR (NoArity (a, c))
       | SOME (_, Ss) => Ss);
-    fun dom_inter c Ss = ListPair.map (inter_sort classes) (dom c, Ss);
+    fun dom_inter c Ss = ListPair.map (inter_sort algebra) (dom c, Ss);
   in
     (case S of
       [] => raise Fail "Unknown domain of empty intersection"
@@ -277,13 +313,13 @@
 
 (* of_sort *)
 
-fun of_sort (classes, arities) =
+fun of_sort algebra =
   let
     fun ofS (_, []) = true
-      | ofS (TFree (_, S), S') = sort_le classes (S, S')
-      | ofS (TVar (_, S), S') = sort_le classes (S, S')
+      | ofS (TFree (_, S), S') = sort_le algebra (S, S')
+      | ofS (TVar (_, S), S') = sort_le algebra (S, S')
       | ofS (Type (a, Ts), S) =
-          let val Ss = mg_domain (classes, arities) a S in
+          let val Ss = mg_domain algebra a S in
             ListPair.all ofS (Ts, Ss)
           end handle CLASS_ERROR _ => false;
   in ofS end;
@@ -291,8 +327,9 @@
 
 (* of_sort_derivation *)
 
-fun of_sort_derivation pp (classes, arities) {classrel, constructor, variable} =
+fun of_sort_derivation pp algebra {classrel, constructor, variable} =
   let
+    val {classes, arities} = rep_algebra algebra;
     fun weaken_path (x, c1 :: c2 :: cs) = weaken_path (classrel (x, c1) c2, c2 :: cs)
       | weaken_path (x, _) = x;
     fun weaken (x, c1) c2 =
@@ -301,7 +338,7 @@
       | cs :: _ => weaken_path (x, cs));
 
     fun weakens S1 S2 = S2 |> map (fn c2 =>
-      (case S1 |> find_first (fn (_, c1) => class_le classes (c1, c2)) of
+      (case S1 |> find_first (fn (_, c1) => class_le algebra (c1, c2)) of
         SOME d1 => weaken d1 c2
       | NONE => error ("Cannot derive subsort relation " ^
           Pretty.string_of_sort pp (map #2 S1) ^ " < " ^ Pretty.string_of_sort pp S2)));
@@ -309,7 +346,7 @@
     fun derive _ [] = []
       | derive (Type (a, Ts)) S =
           let
-            val Ss = mg_domain (classes, arities) a S;
+            val Ss = mg_domain algebra a S;
             val dom = map2 (fn T => fn S => derive T S ~~ S) Ts Ss;
           in
             S |> map (fn c =>
@@ -324,12 +361,12 @@
 
 (* witness_sorts *)
 
-fun witness_sorts (classes, arities) types hyps sorts =
+fun witness_sorts algebra types hyps sorts =
   let
-    fun le S1 S2 = sort_le classes (S1, S2);
+    fun le S1 S2 = sort_le algebra (S1, S2);
     fun get_solved S2 (T, S1) = if le S1 S2 then SOME (T, S2) else NONE;
     fun get_hyp S2 S1 = if le S1 S2 then SOME (TFree ("'hyp", S1), S2) else NONE;
-    fun mg_dom t S = SOME (mg_domain (classes, arities) t S) handle CLASS_ERROR _ => NONE;
+    fun mg_dom t S = SOME (mg_domain algebra t S) handle CLASS_ERROR _ => NONE;
 
     fun witn_sort _ [] solved_failed = (SOME (propT, []), solved_failed)
       | witn_sort path S (solved, failed) =