src/HOL/Tools/transfer.ML

     Author:     Jeremy Avigad, Carnegie Mellon University
 *)
 
 signature TRANSFER =
 sig
-  type data
   type entry
-  val get: Proof.context -> data
-  val del: attribute
+  val get: Proof.context -> (thm * entry) list
+  val del: thm -> Context.generic -> Context.generic
   val setup: theory -> theory
 end;
 
 structure Transfer : TRANSFER =
 struct
+
+(* data administration *)
+
+val transM_pat = (Thm.dest_arg1 o Thm.dest_arg o cprop_of) @{thm TransferMorphism_def};
 
 type entry = { inj : thm list, emb : thm list, ret : thm list, cong : thm list,
   guess : bool, hints : string list };
 
 fun merge_entry ({ inj = inj1, emb = emb1, ret = ret1, cong = cong1, guess = guess1, hints = hints1 } : entry,
   { inj = inj2, emb = emb2, ret = ret2, cong = cong2, guess = guess2, hints = hints2 } : entry) =
     { inj = merge Thm.eq_thm (inj1, inj2), emb = merge Thm.eq_thm (emb1, emb2),
       ret = merge Thm.eq_thm (ret1, ret2), cong = merge Thm.eq_thm (cong1, cong2),
       guess = guess1 andalso guess2, hints = merge (op =) (hints1, hints2) };
 
-type data = simpset * (thm * entry) list;
-
 structure Data = Generic_Data
 (
-  type T = data;
-  val empty = (HOL_ss, []);
+  type T = (thm * entry) list;
+  val empty = [];
   val extend  = I;
-  fun merge ((ss1, e1), (ss2, e2)) : T =
-    (merge_ss (ss1, ss2), AList.join Thm.eq_thm (K merge_entry) (e1, e2));
+  val merge = AList.join Thm.eq_thm (K merge_entry);
 );
 
 val get = Data.get o Context.Proof;
 
-fun del_data key = apsnd (remove (eq_fst Thm.eq_thm) (key, []));
-
-val del = Thm.declaration_attribute (Data.map o del_data);
-val add_ss = Thm.declaration_attribute
-   (fn th => Data.map (fn (ss,data) => (ss addsimps [th], data)));
-
-val del_ss = Thm.declaration_attribute
-   (fn th => Data.map (fn (ss,data) => (ss delsimps [th], data)));
-
-val transM_pat = (Thm.dest_arg1 o Thm.dest_arg o cprop_of) @{thm TransferMorphism_def};
-
-fun merge_update eq m (k,v) [] = [(k,v)]
-  | merge_update eq m (k,v) ((k',v')::al) =
-           if eq (k,k') then (k',m (v,v')):: al else (k',v') :: merge_update eq m (k,v) al
-
-fun simpset_of_entry injonly {inj = inj, emb = emb, ret = ret, cong = cg, guess = g, hints = hints} =
- HOL_ss addsimps inj addsimps (if injonly then [] else emb@ret) addcongs cg;
-
-fun basic_transfer_rule injonly a0 D0 e leave ctxt0 th =
+fun del key = Data.map (remove (eq_fst Thm.eq_thm) (key, []))
+
+val del_attribute = Thm.declaration_attribute del;
+
+
+(* applying transfer data *)
+
+fun build_simpset inj_only {inj = inj, emb = emb, ret = ret, cong = cg, guess = g, hints = hints} =
+  HOL_ss addsimps inj addsimps (if inj_only then [] else emb @ ret) addcongs cg;
+
+fun basic_transfer_rule inj_only a0 D0 e leave ctxt0 th =
  let
-  val ([a,D], ctxt) = apfst (map Drule.dest_term o snd) (Variable.import true (map Drule.mk_term [a0, D0]) ctxt0)
+  val ([a,D], ctxt) = apfst (map Drule.dest_term o snd)
+    (Variable.import true (map Drule.mk_term [a0, D0]) ctxt0);
   val (aT,bT) =
      let val T = typ_of (ctyp_of_term a)
      in (Term.range_type T, Term.domain_type T)
-     end
-  val ctxt' = (Variable.declare_term (term_of a) o Variable.declare_term (term_of D) o Variable.declare_thm th) ctxt
-  val ns = filter (fn i => Type.could_unify (snd i, aT) andalso not (fst (fst i) mem_string leave)) (Term.add_vars (prop_of th) [])
-  val (ins, ctxt'') = Variable.variant_fixes (map (fst o fst) ns) ctxt'
-  val cns = map ((cterm_of o ProofContext.theory_of) ctxt'' o Var) ns
-  val cfis = map ((cterm_of o ProofContext.theory_of) ctxt'' o (fn n => Free (n, bT))) ins
+     end;
+  val ctxt' = (Variable.declare_term (term_of a) o Variable.declare_term (term_of D)
+    o Variable.declare_thm th) ctxt;
+  val ns = filter (fn i => Type.could_unify (snd i, aT) andalso
+    not (fst (fst i) mem_string leave)) (Term.add_vars (prop_of th) []);
+  val (ins, ctxt'') = Variable.variant_fixes (map (fst o fst) ns) ctxt';
+  val cns = map ((cterm_of o ProofContext.theory_of) ctxt'' o Var) ns;
+  val cfis = map ((cterm_of o ProofContext.theory_of) ctxt'' o
+    (fn n => Free (n, bT))) ins;
   val cis = map (Thm.capply a) cfis
-  val (hs,ctxt''') = Assumption.add_assumes (map (fn ct => Thm.capply @{cterm "Trueprop"} (Thm.capply D ct)) cfis) ctxt''
-  val th1 = Drule.cterm_instantiate (cns ~~ cis) th
-  val th2 = fold Thm.elim_implies hs (fold_rev implies_intr (map cprop_of hs) th1)
-  val th3 = Simplifier.asm_full_simplify (Simplifier.context ctxt''' (simpset_of_entry injonly e))
-                                         (fold_rev implies_intr (map cprop_of hs) th2)
+  val (hs, ctxt''') = Assumption.add_assumes (map (fn ct =>
+    Thm.capply @{cterm "Trueprop"} (Thm.capply D ct)) cfis) ctxt'';
+  val th1 = Drule.cterm_instantiate (cns ~~ cis) th;
+  val th2 = fold Thm.elim_implies hs (fold_rev implies_intr (map cprop_of hs) th1);
+  val th3 = Simplifier.asm_full_simplify (Simplifier.context ctxt'''
+    (build_simpset inj_only e)) (fold_rev implies_intr (map cprop_of hs) th2);
 in hd (Variable.export ctxt''' ctxt0 [th3]) end;
 
-local
-fun transfer_ruleh a D leave ctxt th =
- let val (ss,al) = get ctxt
-     val a0 = cterm_of (ProofContext.theory_of ctxt) a
-     val D0 = cterm_of (ProofContext.theory_of ctxt) D
-     fun h (th', e) = let val (a',D') = (Thm.dest_binop o Thm.dest_arg o cprop_of) th'
-                 in if a0 aconvc a' andalso D0 aconvc D' then SOME e else NONE
-                 end
- in case get_first h al of
-      SOME e => basic_transfer_rule false a0 D0 e leave ctxt th
-    | NONE => error "Transfer: corresponding instance not found in context-data"
- end
-in fun transfer_rule (a,D) leave (gctxt,th) =
-   (gctxt, transfer_ruleh a D leave (Context.proof_of gctxt) th)
-end;
-
-fun  splits P [] = []
-   | splits P (xxs as (x::xs)) =
-    let val pss = filter (P x) xxs
+fun transfer_rule (a, D) leave (gctxt, th) =
+  let
+    fun transfer_ruleh a D leave ctxt th =
+      let
+        val al = get ctxt
+        val a0 = cterm_of (ProofContext.theory_of ctxt) a
+        val D0 = cterm_of (ProofContext.theory_of ctxt) D
+        fun h (th', e) =
+          let
+            val (a',D') = (Thm.dest_binop o Thm.dest_arg o cprop_of) th'
+          in if a0 aconvc a' andalso D0 aconvc D' then SOME e else NONE end
+      in case get_first h al of
+          SOME e => basic_transfer_rule false a0 D0 e leave ctxt th
+        | NONE => error "Transfer: corresponding instance not found in context data"
+      end;
+  in 
+    (gctxt, transfer_ruleh a D leave (Context.proof_of gctxt) th)
+  end;
+
+fun splits P [] = []
+  | splits P (xxs as (x :: xs)) =
+      let
+        val pss = filter (P x) xxs
         val qss = filter_out (P x) xxs
-    in if null pss then [qss] else if null qss then [pss] else pss:: splits P qss
-    end
-
-fun all_transfers leave (gctxt,th) =
- let
-  val ctxt = Context.proof_of gctxt
-  val tys = map snd (Term.add_vars (prop_of th) [])
-  val _ = if null tys then error "transfer: Unable to guess instance" else ()
-  val tyss = splits (curry Type.could_unify) tys
-  val get_ty = typ_of o ctyp_of_term o fst o Thm.dest_binop o Thm.dest_arg o cprop_of
-  val get_aD = Thm.dest_binop o Thm.dest_arg o cprop_of
-  val insts =
-    map_filter (fn tys =>
-      get_first (fn (k,ss) =>
-        if Type.could_unify (hd tys, range_type (get_ty k))
-        then SOME (get_aD k, ss)
-        else NONE) (snd (get ctxt))) tyss
-  val _ =
-    if null insts then
-      error "Transfer guesser: there were no possible instances, use direction: in order to provide a direction"
-    else ()
-  val ths = map  (fn ((a,D),e) => basic_transfer_rule false a D e leave ctxt th) insts
-  val cth = Conjunction.intr_balanced ths
- in (gctxt, cth)
- end;
-
-fun transfer_rule_by_hint ls leave (gctxt,th) =
- let
-  val ctxt = Context.proof_of gctxt
-  val get_aD = Thm.dest_binop o Thm.dest_arg o cprop_of
-  val insts =
-    map_filter (fn (k,e) => if exists (member (op =) (#hints e)) ls
-          then SOME (get_aD k, e) else NONE)
-        (snd (get ctxt))
-  val _ = if null insts then error "Transfer: No labels provided are stored in the context" else ()
-  val ths = map  (fn ((a,D),e) => basic_transfer_rule false a D e leave ctxt th) insts
-  val cth = Conjunction.intr_balanced ths
- in (gctxt, cth)
- end;
-
+      in if null pss then [qss] else if null qss then [pss] else pss:: splits P qss end
+
+fun all_transfers leave (gctxt, th) =
+  let
+    val ctxt = Context.proof_of gctxt;
+    val tys = map snd (Term.add_vars (prop_of th) []);
+    val _ = if null tys then error "transfer: Unable to guess instance" else ();
+    val tyss = splits (curry Type.could_unify) tys;
+    val get_ty = typ_of o ctyp_of_term o fst o Thm.dest_binop o Thm.dest_arg o cprop_of;
+    val get_aD = Thm.dest_binop o Thm.dest_arg o cprop_of;
+    val insts =
+      map_filter (fn tys =>
+        get_first (fn (k,ss) =>
+          if Type.could_unify (hd tys, range_type (get_ty k))
+          then SOME (get_aD k, ss)
+          else NONE) (get ctxt)) tyss;
+    val _ =
+      if null insts then
+        error "Transfer guesser: there were no possible instances, use direction: in order to provide a direction"
+      else ();
+    val ths = map (fn ((a, D), e) => basic_transfer_rule false a D e leave ctxt th) insts;
+    val cth = Conjunction.intr_balanced ths;
+  in (gctxt, cth) end;
+
+fun transfer_rule_by_hint ls leave (gctxt, th) =
+  let
+    val ctxt = Context.proof_of gctxt;
+    val get_aD = Thm.dest_binop o Thm.dest_arg o cprop_of;
+    val insts = map_filter (fn (k,e) => if exists (member (op =) (#hints e)) ls
+      then SOME (get_aD k, e) else NONE) (get ctxt);
+    val _ = if null insts then error "Transfer: No labels provided are stored in the context" else ();
+    val ths = map  (fn ((a,D),e) => basic_transfer_rule false a D e leave ctxt th) insts;
+    val cth = Conjunction.intr_balanced ths;
+  in (gctxt, cth) end;
 
 fun transferred_attribute ls NONE leave =
-         if null ls then all_transfers leave else transfer_rule_by_hint ls leave
-  | transferred_attribute _ (SOME (a,D)) leave = transfer_rule (a,D) leave
-
-
-(* Add data to the context *)
-
-fun gen_merge_entries {inj = inj0, emb = emb0, ret = ret0, cong = cg0, guess = g0, hints = hints0}
-                      ({inj = inj1, emb = emb1, ret = ret1, cong = cg1, guess = g1, hints = hints1},
-                       {inj = inj2, emb = emb2, ret = ret2, cong = cg2, guess = g2, hints = hints2})
- =
- let fun h xs0 xs ys = subtract Thm.eq_thm xs0 (merge Thm.eq_thm (xs,ys)) in
- {inj = h inj0 inj1 inj2, emb = h emb0 emb1 emb2,
-  ret = h ret0 ret1 ret2, cong = h cg0 cg1 cg2, guess = g1 andalso g2,
-  hints = subtract (op = : string*string -> bool) hints0
-            (union (op =) hints1 hints2)}
- end;
-
-local
- val h = curry (merge Thm.eq_thm)
-in
-fun merge_entries ({inj = inj1, emb = emb1, ret = ret1, cong = cg1, guess = g1, hints = hints1},
-                   {inj = inj2, emb = emb2, ret = ret2, cong = cg2, guess = g2, hints = hints2}) =
-    {inj = h inj1 inj2, emb = h emb1 emb2, ret = h ret1 ret2, cong = h cg1 cg2, guess = g1 andalso g2, hints = union (op =) hints1 hints2}
-end;
-
-fun add ((inja,injd), (emba,embd), (reta,retd), (cga,cgd), g, (hintsa, hintsd)) =
-  Thm.declaration_attribute (fn key => fn context => context |> Data.map
-   (fn (ss, al) =>
-     let
+      if null ls then all_transfers leave else transfer_rule_by_hint ls leave
+  | transferred_attribute _ (SOME (a, D)) leave = transfer_rule (a, D) leave
+
+
+(* adding transfer data *)
+
+fun merge_update eq m (k, v) [] = [(k, v)]
+  | merge_update eq m (k, v) ((k', v') :: al) =
+      if eq (k, k') then (k', m (v, v')) :: al else (k', v') :: merge_update eq m (k, v) al;
+
+(*? fun merge_update eq m (k, v) = AList.map_entry eq k (fn v' => m (v, v'));*)
+
+fun merge_entries {inj = inj0, emb = emb0, ret = ret0, cong = cg0, guess = g0, hints = hints0}
+      ({inj = inj1, emb = emb1, ret = ret1, cong = cg1, guess = g1, hints = hints1},
+       {inj = inj2, emb = emb2, ret = ret2, cong = cg2, guess = g2, hints = hints2} : entry) =
+  let
+    fun h xs0 xs ys = subtract Thm.eq_thm xs0 (merge Thm.eq_thm (xs, ys))
+  in
+    {inj = h inj0 inj1 inj2, emb = h emb0 emb1 emb2,
+     ret = h ret0 ret1 ret2, cong = h cg0 cg1 cg2, guess = g1 andalso g2,
+     hints = subtract (op =) hints0 (union (op =) hints1 hints2) }
+  end;
+
+fun add ((inja, injd), (emba, embd), (reta, retd), (cga, cgd), g, (hintsa, hintsd)) key =
+  Data.map (fn al =>
+    let
       val _ = Thm.match (transM_pat, Thm.dest_arg (Thm.cprop_of key))
         handle Pattern.MATCH =>
           error "Attribute expected Theorem of the form : TransferMorphism A a B b"
       val e0 = {inj = inja, emb = emba, ret = reta, cong = cga, guess = g, hints = hintsa}
       val ed = {inj = injd, emb = embd, ret = retd, cong = cgd, guess = g, hints = hintsd}

                   | NONE => error "Transfer: can not generate return rules on the fly, either add injectivity axiom or force manual mode with mode: manual")
                else inja
              val ret' = merge Thm.eq_thm (reta,  map (fn th => basic_transfer_rule true a0 D0 {inj = inj', emb = [], ret = [], cong = cga, guess = g, hints = hintsa} [] ctxt0 th RS sym) emba)
          in {inj = inja, emb = emba, ret = ret', cong = cga, guess = g, hints = hintsa} end
         else e0
-    in (ss, merge_update Thm.eq_thm (gen_merge_entries ed) (key, entry) al)
-    end));
-
-
-(* concrete syntax *)
+    in merge_update Thm.eq_thm (merge_entries ed) (key, entry) al
+    end);
+
+fun add_attribute args = Thm.declaration_attribute (add args);
+
+
+(* syntax *)
 
 local
 
 fun keyword k = Scan.lift (Args.$$$ k) >> K ()
 fun keywordC k = Scan.lift (Args.$$$ k -- Args.colon) >> K ()

 
 val transf_add = addscan |-- entry
 in
 
 val install_att_syntax =
-  (Scan.lift (Args.$$$ delN >> K del) ||
+  (Scan.lift (Args.$$$ delN >> K del_attribute) ||
     transf_add
-    >> (fn (((((g, inj), embed), ret), cg), hints) => add (inj, embed, ret, cg, g, hints)))
+    >> (fn (((((g, inj), embed), ret), cg), hints) => add_attribute (inj, embed, ret, cg, g, hints)))
 
 val transferred_att_syntax = (optional names -- Scan.option (keywordC directionN |-- (Args.term -- Args.term))
   -- optional (keywordC leavingN |-- names) >> (fn ((hints, aD),leave) => transferred_attribute hints aD leave));
 
 end;

 (* theory setup *)
 
 val setup =
   Attrib.setup @{binding transfer} install_att_syntax
     "Installs transfer data" #>
-  Attrib.setup @{binding transfer_simps} (Attrib.add_del add_ss del_ss)
-    "simp rules for transfer" #>
   Attrib.setup @{binding transferred} transferred_att_syntax
     "Transfers theorems";
 
 end;