(* Title: Pure/consts.ML
ID: $Id$
Author: Makarius
Polymorphic constants: declarations, abbreviations, additional type
constraints.
*)
signature CONSTS =
sig
type T
val eq_consts: T * T -> bool
val abbrevs_of: T -> string list -> (term * term) list
val dest: T ->
{constants: (typ * term option) NameSpace.table,
constraints: typ NameSpace.table}
val declaration: T -> string -> typ (*exception TYPE*)
val monomorphic: T -> string -> bool (*exception TYPE*)
val constraint: T -> string -> typ (*exception TYPE*)
val space_of: T -> NameSpace.T
val intern: T -> xstring -> string
val extern: T -> string -> xstring
val extern_early: T -> string -> xstring
val syntax: T -> string * mixfix -> string * typ * mixfix
val read_const: T -> string -> term
val certify: Pretty.pp -> Type.tsig -> T -> term -> term (*exception TYPE*)
val typargs: T -> string * typ -> typ list
val instance: T -> string * typ list -> typ
val declare: NameSpace.naming -> (bstring * typ) * bool -> T -> T
val constrain: string * typ option -> T -> T
val expand_abbrevs: bool -> T -> T
val abbreviate: Pretty.pp -> Type.tsig -> NameSpace.naming -> string ->
(bstring * term) * bool -> T -> T
val hide: bool -> string -> T -> T
val empty: T
val merge: T * T -> T
end;
structure Consts: CONSTS =
struct
(** consts type **)
(* datatype T *)
datatype kind =
LogicalConst of int list list |
Abbreviation of term;
type decl =
(typ * kind) *
bool; (*early externing*)
datatype T = Consts of
{decls: (decl * stamp) NameSpace.table,
constraints: typ Symtab.table,
rev_abbrevs: (term * term) list Symtab.table,
expand_abbrevs: bool} * stamp;
fun eq_consts (Consts (_, s1), Consts (_, s2)) = s1 = s2;
fun make_consts (decls, constraints, rev_abbrevs, expand_abbrevs) =
Consts ({decls = decls, constraints = constraints,
expand_abbrevs = expand_abbrevs, rev_abbrevs = rev_abbrevs}, stamp ());
fun map_consts f (Consts ({decls, constraints, rev_abbrevs, expand_abbrevs}, _)) =
make_consts (f (decls, constraints, rev_abbrevs, expand_abbrevs));
fun abbrevs_of (Consts ({rev_abbrevs, ...}, _)) modes =
maps (Symtab.lookup_list rev_abbrevs) modes;
(* dest consts *)
fun dest_kind (LogicalConst _) = NONE
| dest_kind (Abbreviation t) = SOME t;
fun dest (Consts ({decls = (space, decls), constraints, ...}, _)) =
{constants = (space,
Symtab.fold (fn (c, (((T, kind), _), _)) =>
Symtab.update (c, (T, dest_kind kind))) decls Symtab.empty),
constraints = (space, constraints)};
(* lookup consts *)
fun the_const (Consts ({decls = (_, tab), ...}, _)) c =
(case Symtab.lookup tab c of
SOME (decl, _) => decl
| NONE => raise TYPE ("Undeclared constant: " ^ quote c, [], []));
fun logical_const consts c =
(case the_const consts c of
((T, LogicalConst ps), _) => (T, ps)
| _ => raise TYPE ("Illegal abbreviation: " ^ quote c, [], []));
val declaration = #1 oo logical_const;
val type_arguments = #2 oo logical_const;
val monomorphic = null oo type_arguments;
fun constraint (consts as Consts ({constraints, ...}, _)) c =
(case Symtab.lookup constraints c of
SOME T => T
| NONE => #1 (#1 (the_const consts c)));
(* name space and syntax *)
fun space_of (Consts ({decls = (space, _), ...}, _)) = space;
val intern = NameSpace.intern o space_of;
val extern = NameSpace.extern o space_of;
fun extern_early consts c =
(case try (the_const consts) c of
SOME (_, false) => Syntax.constN ^ c
| _ => extern consts c);
fun syntax consts (c, mx) =
let
val ((T, _), early) = the_const consts c handle TYPE (msg, _, _) => error msg;
val c' = if early then NameSpace.base c else #1 (Syntax.mixfix_const c mx);
in (c', T, mx) end;
(* read_const *)
fun read_const consts raw_c =
let
val c = intern consts raw_c;
val _ = the_const consts c handle TYPE (msg, _, _) => error msg;
in Const (c, dummyT) end;
(* certify *)
fun certify pp tsig (consts as Consts ({expand_abbrevs, ...}, _)) =
let
fun err msg (c, T) =
raise TYPE (msg ^ " " ^ quote c ^ " :: " ^ Pretty.string_of_typ pp T, [], []);
fun cert tm =
let
val (head, args) = Term.strip_comb tm;
fun comb h = Term.list_comb (h, map cert args);
in
(case head of
Abs (x, T, t) => comb (Abs (x, T, cert t))
| Const (c, T) =>
let
val T' = Type.cert_typ tsig T;
val ((U, kind), _) = the_const consts c;
in
if not (Type.raw_instance (T', U)) then
err "Illegal type for constant" (c, T)
else
(case (kind, expand_abbrevs) of
(Abbreviation u, true) =>
Term.betapplys (Envir.expand_atom T' (U, u) handle TYPE _ =>
err "Illegal type for abbreviation" (c, T), map cert args)
| _ => comb head)
end
| _ => comb head)
end;
in cert end;
(* typargs -- view actual const type as instance of declaration *)
fun subscript (Type (_, Ts)) (i :: is) = subscript (nth Ts i) is
| subscript T [] = T
| subscript T _ = raise Subscript;
fun typargs consts (c, T) = map (subscript T) (type_arguments consts c);
fun instance consts (c, Ts) =
let
val declT = declaration consts c;
val vars = map Term.dest_TVar (typargs consts (c, declT));
in declT |> Term.instantiateT (vars ~~ Ts) end;
(** build consts **)
fun err_dup_consts cs =
error ("Duplicate declaration of constant(s) " ^ commas_quote cs);
fun err_inconsistent_constraints cs =
error ("Inconsistent type constraints for constant(s) " ^ commas_quote cs);
fun extend_decls naming decl tab = NameSpace.extend_table naming (tab, [decl])
handle Symtab.DUPS cs => err_dup_consts cs;
(* name space *)
fun hide fully c = map_consts (fn (decls, constraints, rev_abbrevs, expand_abbrevs) =>
(apfst (NameSpace.hide fully c) decls, constraints, rev_abbrevs, expand_abbrevs));
(* declarations *)
fun declare naming ((c, declT), early) =
map_consts (fn (decls, constraints, rev_abbrevs, expand_abbrevs) =>
let
fun args_of (Type (_, Ts)) pos = args_of_list Ts 0 pos
| args_of (TVar v) pos = insert (eq_fst op =) (v, rev pos)
| args_of (TFree _) _ = I
and args_of_list (T :: Ts) i is = args_of T (i :: is) #> args_of_list Ts (i + 1) is
| args_of_list [] _ _ = I;
val decl = (((declT, LogicalConst (map #2 (rev (args_of declT [] [])))), early), stamp ());
in (extend_decls naming (c, decl) decls, constraints, rev_abbrevs, expand_abbrevs) end);
(* constraints *)
fun constrain (c, C) consts =
consts |> map_consts (fn (decls, constraints, rev_abbrevs, expand_abbrevs) =>
(the_const consts c handle TYPE (msg, _, _) => error msg;
(decls,
constraints |> (case C of SOME T => Symtab.update (c, T) | NONE => Symtab.delete_safe c),
rev_abbrevs, expand_abbrevs)));
(* abbreviations *)
fun expand_abbrevs b = map_consts (fn (decls, constraints, rev_abbrevs, _) =>
(decls, constraints, rev_abbrevs, b));
local
fun strip_abss tm = ([], tm) ::
(case tm of
Abs (a, T, t) =>
if Term.loose_bvar1 (t, 0) then
strip_abss t |> map (fn (xs, b) => ((a, T) :: xs, b))
else []
| _ => []);
fun rev_abbrev const rhs =
let
fun abbrev (xs, body) =
let val vars = fold (fn (x, T) => cons (Var ((x, 0), T))) (Term.rename_wrt_term body xs) []
in (Term.subst_bounds (rev vars, body), Term.list_comb (Const const, vars)) end;
in map abbrev (strip_abss (Envir.beta_eta_contract rhs)) end;
in
fun abbreviate pp tsig naming mode ((c, raw_rhs), early) consts =
let
val rhs = raw_rhs
|> Term.map_term_types (Type.cert_typ tsig)
|> certify pp tsig (consts |> expand_abbrevs false);
val rhs' = rhs
|> certify pp tsig (consts |> expand_abbrevs true);
val T = Term.fastype_of rhs;
in
consts |> map_consts (fn (decls, constraints, rev_abbrevs, expand_abbrevs) =>
let
val decls' = decls
|> extend_decls naming (c, (((T, Abbreviation rhs'), early), stamp ()));
val rev_abbrevs' = rev_abbrevs
|> fold (curry Symtab.update_list mode) (rev_abbrev (NameSpace.full naming c, T) rhs);
in (decls', constraints, rev_abbrevs', expand_abbrevs) end)
end;
end;
(* empty and merge *)
val empty = make_consts (NameSpace.empty_table, Symtab.empty, Symtab.empty, true);
fun merge
(Consts ({decls = decls1, constraints = constraints1,
rev_abbrevs = rev_abbrevs1, expand_abbrevs = expand_abbrevs1}, _),
Consts ({decls = decls2, constraints = constraints2,
rev_abbrevs = rev_abbrevs2, expand_abbrevs = expand_abbrevs2}, _)) =
let
val decls' = NameSpace.merge_tables (eq_snd (op =)) (decls1, decls2)
handle Symtab.DUPS cs => err_dup_consts cs;
val constraints' = Symtab.merge (op =) (constraints1, constraints2)
handle Symtab.DUPS cs => err_inconsistent_constraints cs;
val rev_abbrevs' = (rev_abbrevs1, rev_abbrevs2) |> Symtab.join
(K (Library.merge (fn ((t, u), (t', u')) => t aconv t' andalso u aconv u')));
val expand_abbrevs' = expand_abbrevs1 orelse expand_abbrevs2;
in make_consts (decls', constraints', rev_abbrevs', expand_abbrevs') end;
end;