types to sets: initial commit
authorkuncar
Sun, 30 Oct 2016 13:15:14 +0100
changeset 64431 ae53f4d901a3
parent 64430 1d85ac286c72
child 64432 c381bfd068fd
types to sets: initial commit
src/HOL/Library/Types_To_Sets.thy
src/HOL/Library/Types_To_Sets/internalize_sort.ML
src/HOL/Library/Types_To_Sets/local_typedef.ML
src/HOL/Library/Types_To_Sets/unoverloading.ML
src/HOL/ROOT
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Types_To_Sets.thy	Sun Oct 30 13:15:14 2016 +0100
@@ -0,0 +1,27 @@
+(*  Title:      HOL/Library/Types_To_Sets.thy
+    Author:     Ondřej Kunčar, TU München
+*)
+
+section \<open>From Types to Sets\<close>
+
+text \<open>This theory extends Isabelle/HOL's logic by two new inference rules
+  to allow translation of types to sets as described in 
+  O. Kunčar, A. Popescu: From Types to Sets by Local Type Definitions in Higher-Order Logic
+  available at http://www21.in.tum.de/~kuncar/documents/kuncar-popescu-t2s2016-extended.pdf.\<close>
+
+theory Types_To_Sets
+  imports Main
+begin
+
+subsection \<open>Rules\<close>
+
+text\<open>The following file implements the Local Typedef Rule (LT) and extends the logic by the rule.\<close>
+ML_file "Types_To_Sets/local_typedef.ML"
+
+text\<open>The following file implements the Unoverloading Rule (UO) and extends the logic by the rule.\<close>
+ML_file "Types_To_Sets/unoverloading.ML"
+
+text\<open>The following file implements a derived rule that internalizes type class annotations.\<close>
+ML_file "Types_To_Sets/internalize_sort.ML"
+
+end
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Types_To_Sets/internalize_sort.ML	Sun Oct 30 13:15:14 2016 +0100
@@ -0,0 +1,68 @@
+(*  Title:      internalize_sort.ML
+    Author:     Ondřej Kunčar, TU München
+
+    Implements a derived rule (by using Thm.unconstrainT) that internalizes
+    type class annotations.
+*)
+
+
+(*
+                     \<phi>['a::{c_1, ..., c_n} / 'a]
+---------------------------------------------------------------------
+  class.c_1 ops_1 \<Longrightarrow> ... \<Longrightarrow> class.c_n ops_n \<Longrightarrow> \<phi>['a::type / 'a]
+
+where class.c is the locale predicate associated with type class c and
+ops are operations associated with type class c. For example:
+If c = semigroup_add, then ops = op-, op+, 0, uminus.
+If c = finite, then ops = TYPE('a::type).
+*)
+
+signature INTERNALIZE_SORT =
+sig
+  val internalize_sort:  ctyp -> thm -> typ * thm
+  val internalize_sort_attr: typ -> attribute
+end;
+
+structure Internalize_Sort : INTERNALIZE_SORT =
+struct
+
+fun internalize_sort ctvar thm =
+  let
+    val thy = Thm.theory_of_thm thm;
+    val tvar = Thm.typ_of ctvar;
+    
+    val ((_, assms, classes),_) = Logic.unconstrainT [] (Thm.prop_of thm);
+
+    fun is_proper_class thy = can (Axclass.get_info thy); (* trick by FH *)
+    fun reduce_to_non_proper_sort (TVar (name, sort)) = 
+        TVar (name, Sign.minimize_sort thy (filter_out (is_proper_class thy) (Sign.complete_sort thy sort)))
+      | reduce_to_non_proper_sort _ = error "not supported";
+
+    val data = (map fst classes) ~~ assms;
+    
+    val new_tvar = get_first (fn (tvar', ((ren_tvar, _), _)) => if tvar = tvar' 
+      then SOME (reduce_to_non_proper_sort ren_tvar) else NONE) data
+      |> the_default tvar;
+
+    fun localify class = Class.rules thy class |> snd |> Thm.transfer thy;
+
+    fun discharge_of_class tvar class = Thm.of_class (Thm.global_ctyp_of thy tvar, class);
+
+    val rules = map (fn (tvar', ((ren_tvar, class), _)) => if tvar = tvar' 
+      then (if Class.is_class thy class then localify class else discharge_of_class ren_tvar class)
+      else discharge_of_class ren_tvar class) data;
+  in
+    (new_tvar, (Thm.unconstrainT (Thm.strip_shyps thm) OF rules) |> Drule.zero_var_indexes)
+  end;
+
+val tvar = Args.context -- Args.typ >> (fn (_, v as TFree _) => Logic.varifyT_global v 
+  | (ctxt, t) => error ("Not a type variable: " ^ Syntax.string_of_typ ctxt t));
+
+fun internalize_sort_attr tvar = 
+  Thm.rule_attribute [] (fn context => fn thm => 
+    (snd (internalize_sort (Thm.ctyp_of (Context.proof_of context) tvar) thm)));
+
+val _ = Context.>> (Context.map_theory (Attrib.setup @{binding internalize_sort} 
+  (tvar >> internalize_sort_attr) "internalize a sort"));
+
+end;
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Types_To_Sets/local_typedef.ML	Sun Oct 30 13:15:14 2016 +0100
@@ -0,0 +1,84 @@
+(*  Title:      local_typedef.ML
+    Author:     Ondřej Kunčar, TU München
+
+    Implements the Local Typedef Rule and extends the logic by the rule.
+*)
+
+signature LOCAL_TYPEDEF =
+sig
+  val cancel_type_definition: thm -> thm
+  val cancel_type_definition_attr: attribute
+end;
+
+structure Local_Typedef : LOCAL_TYPEDEF =
+struct
+
+(*
+Local Typedef Rule (LT)
+
+  \<Gamma> \<turnstile> (\<exists>(Rep::\<beta> \<Rightarrow> \<tau>) Abs. type_definition Rep Abs A) \<Longrightarrow> \<phi>
+------------------------------------------------------------- [\<beta> not in \<phi>, \<Gamma>, A;
+                       \<Gamma> \<turnstile> A \<noteq> \<emptyset> \<Longrightarrow> \<phi>                        sort(\<beta>)=HOL.type]
+*)
+
+(** BEGINNING OF THE CRITICAL CODE **)
+
+fun dest_typedef (Const (@{const_name Ex}, _) $ Abs (_, _, 
+      (Const (@{const_name Ex}, _) $ Abs (_, Abs_type,  
+      (Const (@{const_name type_definition}, _)) $ Bound 1 $ Bound 0 $ set)))) = 
+    (Abs_type, set)
+   | dest_typedef t = raise TERM ("dest_typedef", [t]);
+  
+fun cancel_type_definition_cterm thm =
+  let
+    fun err msg = raise THM ("cancel_type_definition: " ^ msg, 0, [thm]);
+
+    val thy = Thm.theory_of_thm thm;
+    val prop = Thm.prop_of thm;
+    val hyps = Thm.hyps_of thm;
+
+    val _ = null (Thm.tpairs_of thm) orelse err "the theorem contains unsolved flex-flex pairs";
+
+    val (typedef_assm, phi) = Logic.dest_implies prop
+      handle TERM _ => err "the theorem is not an implication";
+    val (abs_type, set) = typedef_assm |> HOLogic.dest_Trueprop |> dest_typedef
+      handle TERM _ => err ("the assumption is not of the form " 
+        ^ quote "\<exists>Rep Abs. type_definition Rep Abs A");
+
+    val (repT, absT) = Term.dest_funT abs_type;
+    val _ = Term.is_TVar absT orelse err "the abstract type is not a schematic type variable";
+    val (absT_name, sorts) = Term.dest_TVar absT;
+    
+    val typeS = Sign.defaultS thy;
+    val _ = sorts = typeS orelse err ("the type " ^ quote (fst absT_name) ^ " is not of the sort " 
+      ^ quote (Syntax.string_of_sort_global thy typeS));
+     
+    fun contains_absT tm = member (op=) (Term.add_tvars tm []) (absT_name, sorts);
+    fun err_contains_absT_in msg = err (msg ^ " contains the forbidden type " 
+      ^ quote (fst absT_name));
+    val _ = not (contains_absT phi) orelse err_contains_absT_in "the conclusion";
+    val _ = not (contains_absT set) orelse err_contains_absT_in "the set term";
+    (* the following test is superfluous; the meta hypotheses cannot currently contain TVars *)
+    val _ = not (exists contains_absT hyps) orelse err_contains_absT_in "one of the hypotheses";
+
+    val not_empty_assm = HOLogic.mk_Trueprop
+      (HOLogic.mk_not (HOLogic.mk_eq (set, HOLogic.mk_set repT [])));
+    val prop = Logic.list_implies (hyps @ [not_empty_assm], phi);
+  in
+    Thm.global_cterm_of thy prop |> Thm.weaken_sorts (Thm.shyps_of thm)
+  end;
+
+(** END OF THE CRITICAL CODE **)
+
+val (_, cancel_type_definition_oracle) = Context.>>> (Context.map_theory_result
+  (Thm.add_oracle (@{binding cancel_type_definition}, cancel_type_definition_cterm)));
+
+fun cancel_type_definition thm =  
+  Drule.implies_elim_list (cancel_type_definition_oracle thm) (map Thm.assume (Thm.chyps_of thm));
+
+val cancel_type_definition_attr = Thm.rule_attribute [] (K cancel_type_definition);
+
+val _ = Context.>> (Context.map_theory (Attrib.setup @{binding cancel_type_definition} 
+  (Scan.succeed cancel_type_definition_attr) "cancel a local type definition"));
+
+end;
\ No newline at end of file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Types_To_Sets/unoverloading.ML	Sun Oct 30 13:15:14 2016 +0100
@@ -0,0 +1,139 @@
+(*  Title:      unoverloading.ML
+    Author:     Ondřej Kunčar, TU München
+
+    Implements the Unoverloading Rule and extends the logic by the rule.
+*)
+
+signature UNOVERLOADING =
+sig
+  val unoverload: cterm -> thm -> thm
+  val unoverload_attr: cterm -> attribute
+end;
+
+structure Unoverloading : UNOVERLOADING =
+struct
+
+(*
+Unoverloading Rule (UO)
+
+      \<turnstile> \<phi>[c::\<sigma> / x::\<sigma>]
+---------------------------- [no type or constant or type class in \<phi> 
+        \<turnstile> \<And>x::\<sigma>. \<phi>           depends on c::\<sigma>; c::\<sigma> is undefined]
+*)
+
+(* The following functions match_args, reduction and entries_of were 
+   cloned from defs.ML and theory.ML because the functions are not public.
+   Notice that these functions already belong to the critical code.
+*)
+
+(* >= *)
+fun match_args (Ts, Us) =
+  if Type.could_matches (Ts, Us) then
+    Option.map Envir.subst_type
+      (SOME (Type.raw_matches (Ts, Us) Vartab.empty) handle Type.TYPE_MATCH => NONE)
+  else NONE;
+
+fun reduction defs (deps : Defs.entry list) : Defs.entry list option =
+  let
+    fun reduct Us (Ts, rhs) =
+      (case match_args (Ts, Us) of
+        NONE => NONE
+      | SOME subst => SOME (map (apsnd (map subst)) rhs));
+    fun reducts (d, Us) = get_first (reduct Us) (Defs.get_deps defs d);
+
+    val reds = map (`reducts) deps;
+    val deps' =
+      if forall (is_none o #1) reds then NONE
+      else SOME (fold_rev
+        (fn (NONE, dp) => insert (op =) dp | (SOME dps, _) => fold (insert (op =)) dps) reds []);
+  in deps' end;
+
+fun const_and_typ_entries_of thy tm =
+ let
+   val consts =
+     fold_aterms (fn Const const => insert (op =) (Theory.const_dep thy const) | _ => I) tm [];
+   val types =
+     (fold_types o fold_subtypes) (fn Type t => insert (op =) (Theory.type_dep t) | _ => I) tm [];
+ in
+   consts @ types
+ end;
+
+(* The actual implementation *)
+
+(** BEGINNING OF THE CRITICAL CODE **)
+
+fun fold_atyps_classes f =
+  fold_atyps (fn T as TFree (_, S) => fold (pair T #> f) S 
+    | T as TVar (_, S) => fold (pair T #> f) S 
+    (* just to avoid a warning about incomplete patterns *)
+    | _ => raise TERM ("fold_atyps_classes", [])); 
+
+fun class_entries_of thy tm =
+  let
+    val var_classes = (fold_types o fold_atyps_classes) (insert op=) tm [];
+  in
+    map (Logic.mk_of_class #> Term.head_of #> Term.dest_Const #> Theory.const_dep thy) var_classes
+  end;
+
+fun unoverload_impl cconst thm =
+  let
+    fun err msg = raise THM ("unoverloading: " ^ msg, 0, [thm]);
+
+    val _ = null (Thm.hyps_of thm) orelse err "the theorem has meta hypotheses";
+    val _ = null (Thm.tpairs_of thm) orelse err "the theorem contains unresolved flex-flex pairs";
+    
+    val prop = Thm.prop_of thm;
+    val prop_tfrees = rev (Term.add_tfree_names prop []);
+    val _ = null prop_tfrees orelse err ("the theorem contains free type variables " 
+      ^ commas_quote prop_tfrees);
+
+    val const = Thm.term_of cconst;
+    val _ = Term.is_Const const orelse err "the parameter is is not a constant";
+    val const_tfrees = rev (Term.add_tfree_names const []);
+    val _ = null const_tfrees orelse err ("the constant contains free type variables " 
+      ^ commas_quote const_tfrees);
+
+    val thy = Thm.theory_of_thm thm;
+    val defs = Theory.defs_of thy;
+
+    val const_entry = Theory.const_dep thy (Term.dest_Const const);
+
+    val Uss = Defs.specifications_of defs (fst const_entry);
+    val _ = forall (fn spec => is_none (match_args (#lhs spec, snd const_entry))) Uss 
+      orelse err "the constant instance has already a specification";
+
+    val context = Defs.global_context thy;
+    val prt_entry = Pretty.string_of o Defs.pretty_entry context;
+    
+    fun dep_err (c, Ts) (d, Us) =
+      err (prt_entry (c, Ts) ^ " depends on " ^ prt_entry (d, Us));
+    fun deps_of entry = perhaps_loop (reduction defs) [entry] |> these;
+    fun not_depends_on_const prop_entry = forall (not_equal const_entry) (deps_of prop_entry)
+      orelse dep_err prop_entry const_entry;
+    val prop_entries = const_and_typ_entries_of thy prop @ class_entries_of thy prop;
+    val _ = forall not_depends_on_const prop_entries;
+  in
+    Thm.global_cterm_of thy (Logic.all const prop) |> Thm.weaken_sorts (Thm.shyps_of thm)
+  end;
+
+(** END OF THE CRITICAL CODE **)
+
+val (_, unoverload_oracle) = Context.>>> (Context.map_theory_result
+  (Thm.add_oracle (@{binding unoverload},
+  fn (const, thm) => unoverload_impl const  thm)));
+
+fun unoverload const thm = unoverload_oracle (const, thm);
+
+fun unoverload_attr const = 
+  Thm.rule_attribute [] (fn _ => fn thm => (unoverload const thm));
+
+val const = Args.context -- Args.term  >>
+  (fn (ctxt, tm) => 
+    if not (Term.is_Const tm) 
+    then error ("The term is not a constant: " ^ Syntax.string_of_term ctxt tm)
+    else tm |> Logic.varify_types_global |> Thm.cterm_of ctxt);
+
+val _ = Context.>> (Context.map_theory (Attrib.setup @{binding unoverload} 
+  (const >> unoverload_attr) "unoverload an uninterpreted constant"));
+
+end;
\ No newline at end of file
--- a/src/HOL/ROOT	Sat Oct 29 00:39:33 2016 +0200
+++ b/src/HOL/ROOT	Sun Oct 30 13:15:14 2016 +0100
@@ -38,6 +38,7 @@
     Predicate_Compile_Quickcheck
     Prefix_Order
     Rewrite
+    Types_To_Sets
     (*conflicting type class instantiations*)
     List_lexord
     Sublist_Order