(* Title: HOLCF/Tools/holcf_library.ML
Author: Brian Huffman
Functions for constructing HOLCF types and terms.
*)
structure HOLCF_Library =
struct
infixr 6 ->>;
infix -->>;
infix 9 `;
(*** Operations from Isabelle/HOL ***)
val boolT = HOLogic.boolT;
val natT = HOLogic.natT;
val mk_equals = Logic.mk_equals;
val mk_eq = HOLogic.mk_eq;
val mk_trp = HOLogic.mk_Trueprop;
val mk_fst = HOLogic.mk_fst;
val mk_snd = HOLogic.mk_snd;
val mk_not = HOLogic.mk_not;
val mk_conj = HOLogic.mk_conj;
val mk_disj = HOLogic.mk_disj;
val mk_imp = HOLogic.mk_imp;
fun mk_ex (x, t) = HOLogic.exists_const (fastype_of x) $ Term.lambda x t;
fun mk_all (x, t) = HOLogic.all_const (fastype_of x) $ Term.lambda x t;
(*** Basic HOLCF concepts ***)
fun mk_bottom T = Const (@{const_name UU}, T);
fun below_const T = Const (@{const_name below}, [T, T] ---> boolT);
fun mk_below (t, u) = below_const (fastype_of t) $ t $ u;
fun mk_undef t = mk_eq (t, mk_bottom (fastype_of t));
fun mk_defined t = mk_not (mk_undef t);
fun mk_adm t =
Const (@{const_name adm}, fastype_of t --> boolT) $ t;
fun mk_compact t =
Const (@{const_name compact}, fastype_of t --> boolT) $ t;
fun mk_cont t =
Const (@{const_name cont}, fastype_of t --> boolT) $ t;
fun mk_chain t =
Const (@{const_name chain}, Term.fastype_of t --> boolT) $ t;
fun mk_lub t =
let
val T = Term.range_type (Term.fastype_of t);
val lub_const = Const (@{const_name lub}, (T --> boolT) --> T);
val UNIV_const = @{term "UNIV :: nat set"};
val image_type = (natT --> T) --> (natT --> boolT) --> T --> boolT;
val image_const = Const (@{const_name image}, image_type);
in
lub_const $ (image_const $ t $ UNIV_const)
end;
(*** Continuous function space ***)
fun mk_cfunT (T, U) = Type(@{type_name cfun}, [T, U]);
val (op ->>) = mk_cfunT;
val (op -->>) = Library.foldr mk_cfunT;
fun dest_cfunT (Type(@{type_name cfun}, [T, U])) = (T, U)
| dest_cfunT T = raise TYPE ("dest_cfunT", [T], []);
fun capply_const (S, T) =
Const(@{const_name Rep_CFun}, (S ->> T) --> (S --> T));
fun cabs_const (S, T) =
Const(@{const_name Abs_CFun}, (S --> T) --> (S ->> T));
fun mk_cabs t =
let val T = fastype_of t
in cabs_const (Term.domain_type T, Term.range_type T) $ t end
(* builds the expression (% v1 v2 .. vn. rhs) *)
fun lambdas [] rhs = rhs
| lambdas (v::vs) rhs = Term.lambda v (lambdas vs rhs);
(* builds the expression (LAM v. rhs) *)
fun big_lambda v rhs =
cabs_const (fastype_of v, fastype_of rhs) $ Term.lambda v rhs;
(* builds the expression (LAM v1 v2 .. vn. rhs) *)
fun big_lambdas [] rhs = rhs
| big_lambdas (v::vs) rhs = big_lambda v (big_lambdas vs rhs);
fun mk_capply (t, u) =
let val (S, T) =
case fastype_of t of
Type(@{type_name cfun}, [S, T]) => (S, T)
| _ => raise TERM ("mk_capply " ^ ML_Syntax.print_list ML_Syntax.print_term [t, u], [t, u]);
in capply_const (S, T) $ t $ u end;
val (op `) = mk_capply;
val list_ccomb : term * term list -> term = Library.foldl mk_capply;
fun mk_ID T = Const (@{const_name ID}, T ->> T);
fun cfcomp_const (T, U, V) =
Const (@{const_name cfcomp}, (U ->> V) ->> (T ->> U) ->> (T ->> V));
fun mk_cfcomp (f, g) =
let
val (U, V) = dest_cfunT (fastype_of f);
val (T, U') = dest_cfunT (fastype_of g);
in
if U = U'
then mk_capply (mk_capply (cfcomp_const (T, U, V), f), g)
else raise TYPE ("mk_cfcomp", [U, U'], [f, g])
end;
fun strictify_const T = Const (@{const_name strictify}, T ->> T);
fun mk_strictify t = strictify_const (fastype_of t) ` t;
fun mk_strict t =
let val (T, U) = dest_cfunT (fastype_of t);
in mk_eq (t ` mk_bottom T, mk_bottom U) end;
(*** Product type ***)
val mk_prodT = HOLogic.mk_prodT
fun mk_tupleT [] = HOLogic.unitT
| mk_tupleT [T] = T
| mk_tupleT (T :: Ts) = mk_prodT (T, mk_tupleT Ts);
(* builds the expression (v1,v2,..,vn) *)
fun mk_tuple [] = HOLogic.unit
| mk_tuple (t::[]) = t
| mk_tuple (t::ts) = HOLogic.mk_prod (t, mk_tuple ts);
(* builds the expression (%(v1,v2,..,vn). rhs) *)
fun lambda_tuple [] rhs = Term.lambda (Free("unit", HOLogic.unitT)) rhs
| lambda_tuple (v::[]) rhs = Term.lambda v rhs
| lambda_tuple (v::vs) rhs =
HOLogic.mk_split (Term.lambda v (lambda_tuple vs rhs));
(*** Lifted cpo type ***)
fun mk_upT T = Type(@{type_name "u"}, [T]);
fun dest_upT (Type(@{type_name "u"}, [T])) = T
| dest_upT T = raise TYPE ("dest_upT", [T], []);
fun up_const T = Const(@{const_name up}, T ->> mk_upT T);
fun mk_up t = up_const (fastype_of t) ` t;
fun fup_const (T, U) =
Const(@{const_name fup}, (T ->> U) ->> mk_upT T ->> U);
fun mk_fup t = fup_const (dest_cfunT (fastype_of t)) ` t;
fun from_up T = fup_const (T, T) ` mk_ID T;
(*** Lifted unit type ***)
val oneT = @{typ "one"};
fun one_when_const T = Const (@{const_name one_when}, T ->> oneT ->> T);
fun mk_one_when t = one_when_const (fastype_of t) ` t;
(*** Strict product type ***)
fun mk_sprodT (T, U) = Type(@{type_name sprod}, [T, U]);
fun dest_sprodT (Type(@{type_name sprod}, [T, U])) = (T, U)
| dest_sprodT T = raise TYPE ("dest_sprodT", [T], []);
fun spair_const (T, U) =
Const(@{const_name spair}, T ->> U ->> mk_sprodT (T, U));
(* builds the expression (:t, u:) *)
fun mk_spair (t, u) =
spair_const (fastype_of t, fastype_of u) ` t ` u;
(* builds the expression (:t1,t2,..,tn:) *)
fun mk_stuple [] = @{term "ONE"}
| mk_stuple (t::[]) = t
| mk_stuple (t::ts) = mk_spair (t, mk_stuple ts);
fun sfst_const (T, U) =
Const(@{const_name sfst}, mk_sprodT (T, U) ->> T);
fun ssnd_const (T, U) =
Const(@{const_name ssnd}, mk_sprodT (T, U) ->> U);
fun ssplit_const (T, U, V) =
Const (@{const_name ssplit}, (T ->> U ->> V) ->> mk_sprodT (T, U) ->> V);
fun mk_ssplit t =
let val (T, (U, V)) = apsnd dest_cfunT (dest_cfunT (fastype_of t));
in ssplit_const (T, U, V) ` t end;
(*** Strict sum type ***)
fun mk_ssumT (T, U) = Type(@{type_name ssum}, [T, U]);
fun dest_ssumT (Type(@{type_name ssum}, [T, U])) = (T, U)
| dest_ssumT T = raise TYPE ("dest_ssumT", [T], []);
fun sinl_const (T, U) = Const(@{const_name sinl}, T ->> mk_ssumT (T, U));
fun sinr_const (T, U) = Const(@{const_name sinr}, U ->> mk_ssumT (T, U));
(* builds the list [sinl(t1), sinl(sinr(t2)), ... sinr(...sinr(tn))] *)
fun mk_sinjects ts =
let
val Ts = map fastype_of ts;
fun combine (t, T) (us, U) =
let
val v = sinl_const (T, U) ` t;
val vs = map (fn u => sinr_const (T, U) ` u) us;
in
(v::vs, mk_ssumT (T, U))
end
fun inj [] = raise Fail "mk_sinjects: empty list"
| inj ((t, T)::[]) = ([t], T)
| inj ((t, T)::ts) = combine (t, T) (inj ts);
in
fst (inj (ts ~~ Ts))
end;
fun sscase_const (T, U, V) =
Const(@{const_name sscase},
(T ->> V) ->> (U ->> V) ->> mk_ssumT (T, U) ->> V);
fun mk_sscase (t, u) =
let val (T, V) = dest_cfunT (fastype_of t);
val (U, V) = dest_cfunT (fastype_of u);
in sscase_const (T, U, V) ` t ` u end;
fun from_sinl (T, U) =
sscase_const (T, U, T) ` mk_ID T ` mk_bottom (U ->> T);
fun from_sinr (T, U) =
sscase_const (T, U, U) ` mk_bottom (T ->> U) ` mk_ID U;
(*** pattern match monad type ***)
fun mk_matchT T = Type (@{type_name "match"}, [T]);
fun dest_matchT (Type(@{type_name "match"}, [T])) = T
| dest_matchT T = raise TYPE ("dest_matchT", [T], []);
fun mk_fail T = Const (@{const_name "Fixrec.fail"}, mk_matchT T);
fun succeed_const T = Const (@{const_name "Fixrec.succeed"}, T ->> mk_matchT T);
fun mk_succeed t = succeed_const (fastype_of t) ` t;
(*** lifted boolean type ***)
val trT = @{typ "tr"};
(*** theory of fixed points ***)
fun mk_fix t =
let val (T, _) = dest_cfunT (fastype_of t)
in mk_capply (Const(@{const_name fix}, (T ->> T) ->> T), t) end;
fun iterate_const T =
Const (@{const_name iterate}, natT --> (T ->> T) ->> (T ->> T));
fun mk_iterate (n, f) =
let val (T, _) = dest_cfunT (Term.fastype_of f);
in (iterate_const T $ n) ` f ` mk_bottom T end;
end;