(* 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 the_type: T -> string -> typ (*exception TYPE*)
val the_abbreviation: T -> string -> typ * term (*exception TYPE*)
val type_scheme: T -> string -> typ (*exception TYPE*)
val the_tags: T -> string -> Properties.T (*exception TYPE*)
val is_monomorphic: T -> string -> bool (*exception TYPE*)
val the_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 syntax_name: T -> string -> string
val read_const: T -> string -> term
val certify: Pretty.pp -> Type.tsig -> bool -> T -> term -> term (*exception TYPE*)
val typargs: T -> string * typ -> typ list
val instance: T -> string * typ list -> typ
val declare: bool -> NameSpace.naming -> Properties.T -> (Binding.T * typ) -> T -> T
val constrain: string * typ option -> T -> T
val abbreviate: Pretty.pp -> Type.tsig -> NameSpace.naming -> string -> Properties.T ->
Binding.T * term -> T -> (term * term) * T
val revert_abbrev: string -> string -> 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 *)
type decl = {T: typ, typargs: int list list, tags: Properties.T, authentic: bool};
type abbrev = {rhs: term, normal_rhs: term, force_expand: bool};
datatype T = Consts of
{decls: ((decl * abbrev option) * serial) NameSpace.table,
constraints: typ Symtab.table,
rev_abbrevs: (term * term) list Symtab.table} * stamp;
fun eq_consts (Consts (_, s1), Consts (_, s2)) = s1 = s2;
fun make_consts (decls, constraints, rev_abbrevs) =
Consts ({decls = decls, constraints = constraints, rev_abbrevs = rev_abbrevs}, stamp ());
fun map_consts f (Consts ({decls, constraints, rev_abbrevs}, _)) =
make_consts (f (decls, constraints, rev_abbrevs));
fun abbrevs_of (Consts ({rev_abbrevs, ...}, _)) modes =
maps (Symtab.lookup_list rev_abbrevs) modes;
(* dest consts *)
fun dest (Consts ({decls = (space, decls), constraints, ...}, _)) =
{constants = (space,
Symtab.fold (fn (c, (({T, ...}, abbr), _)) =>
Symtab.update (c, (T, Option.map #rhs abbr))) 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 ("Unknown constant: " ^ quote c, [], []));
fun the_type consts c =
(case the_const consts c of
({T, ...}, NONE) => T
| _ => raise TYPE ("Not a logical constant: " ^ quote c, [], []));
fun the_abbreviation consts c =
(case the_const consts c of
({T, ...}, SOME {rhs, ...}) => (T, rhs)
| _ => raise TYPE ("Not an abbreviated constant: " ^ quote c, [], []));
val the_decl = #1 oo the_const;
val type_scheme = #T oo the_decl;
val type_arguments = #typargs oo the_decl;
val the_tags = #tags oo the_decl;
val is_monomorphic = null oo type_arguments;
fun the_constraint (consts as Consts ({constraints, ...}, _)) c =
(case Symtab.lookup constraints c of
SOME T => T
| NONE => type_scheme 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 ({authentic = true, ...}, _) => Syntax.constN ^ c
| _ => extern consts c);
fun syntax consts (c, mx) =
let
val ({T, authentic, ...}, _) = the_const consts c handle TYPE (msg, _, _) => error msg;
val c' = if authentic then Syntax.constN ^ c else NameSpace.base c;
in (c', T, mx) end;
fun syntax_name consts c = #1 (syntax consts (c, NoSyn));
(* read_const *)
fun read_const consts raw_c =
let
val c = intern consts raw_c;
val T = type_scheme consts c handle TYPE (msg, _, _) => error msg;
in Const (c, T) end;
(* certify *)
fun certify pp tsig do_expand consts =
let
fun err msg (c, T) =
raise TYPE (msg ^ " " ^ quote c ^ " :: " ^ Pretty.string_of_typ pp T, [], []);
val certT = Type.cert_typ tsig;
fun cert tm =
let
val (head, args) = Term.strip_comb tm;
val args' = map cert args;
fun comb head' = Term.list_comb (head', args');
in
(case head of
Abs (x, T, t) => comb (Abs (x, certT T, cert t))
| Const (c, T) =>
let
val T' = certT T;
val ({T = U, ...}, abbr) = the_const consts c;
fun expand u =
Term.betapplys (Envir.expand_atom T' (U, u) handle TYPE _ =>
err "Illegal type for abbreviation" (c, T), args');
in
if not (Type.raw_instance (T', U)) then
err "Illegal type for constant" (c, T)
else
(case abbr of
SOME {rhs, normal_rhs, force_expand} =>
if do_expand then expand normal_rhs
else if force_expand then expand rhs
else comb head
| _ => comb head)
end
| _ => comb head)
end;
in cert end;
(* typargs -- view actual const type as instance of declaration *)
local
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;
fun subscript (Type (_, Ts)) (i :: is) = subscript (nth Ts i) is
| subscript T [] = T
| subscript T _ = raise Subscript;
in
fun typargs_of T = map #2 (rev (args_of T [] []));
fun typargs consts (c, T) = map (subscript T) (type_arguments consts c);
end;
fun instance consts (c, Ts) =
let
val declT = type_scheme consts c;
val vars = map Term.dest_TVar (typargs consts (c, declT));
val inst = vars ~~ Ts handle UnequalLengths =>
raise TYPE ("Consts.instance", Ts, [Const (c, dummyT)]);
in declT |> TermSubst.instantiateT inst end;
(** build consts **)
fun err_dup_const c =
error ("Duplicate declaration of constant " ^ quote c);
fun extend_decls naming decl tab = NameSpace.bind naming decl tab
handle Symtab.DUP c => err_dup_const c;
(* name space *)
fun hide fully c = map_consts (fn (decls, constraints, rev_abbrevs) =>
(apfst (NameSpace.hide fully c) decls, constraints, rev_abbrevs));
(* declarations *)
fun declare authentic naming tags (b, declT) = map_consts (fn (decls, constraints, rev_abbrevs) =>
let
val tags' = tags |> Position.default_properties (Position.thread_data ());
val decl = {T = declT, typargs = typargs_of declT, tags = tags', authentic = authentic};
val (_, decls') = decls |> extend_decls naming (b, ((decl, NONE), serial ()));
in (decls', constraints, rev_abbrevs) end);
(* constraints *)
fun constrain (c, C) consts =
consts |> map_consts (fn (decls, constraints, rev_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)));
(* abbreviations *)
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 lhs 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 (lhs, vars)) end;
in map abbrev (strip_abss (Envir.beta_eta_contract rhs)) end;
in
fun abbreviate pp tsig naming mode tags (b, raw_rhs) consts =
let
val cert_term = certify pp tsig false consts;
val expand_term = certify pp tsig true consts;
val force_expand = mode = PrintMode.internal;
val rhs = raw_rhs
|> Term.map_types (Type.cert_typ tsig)
|> cert_term;
val normal_rhs = expand_term rhs;
val T = Term.fastype_of rhs;
val lhs = Const (NameSpace.full_name naming b, T);
fun err msg = (warning (* FIXME should be error *) (msg ^ " on rhs of abbreviation:\n" ^
Pretty.string_of_term pp (Logic.mk_equals (lhs, rhs))); true);
val _ = Term.exists_subterm Term.is_Var rhs andalso err "Illegal schematic variables";
val _ = null (Term.hidden_polymorphism rhs) orelse err "Extra type variables";
in
consts |> map_consts (fn (decls, constraints, rev_abbrevs) =>
let
val tags' = tags |> Position.default_properties (Position.thread_data ());
val decl = {T = T, typargs = typargs_of T, tags = tags', authentic = true};
val abbr = {rhs = rhs, normal_rhs = normal_rhs, force_expand = force_expand};
val (_, decls') = decls
|> extend_decls naming (b, ((decl, SOME abbr), serial ()));
val rev_abbrevs' = rev_abbrevs
|> fold (curry Symtab.cons_list mode) (rev_abbrev lhs rhs);
in (decls', constraints, rev_abbrevs') end)
|> pair (lhs, rhs)
end;
fun revert_abbrev mode c consts = consts |> map_consts (fn (decls, constraints, rev_abbrevs) =>
let
val (T, rhs) = the_abbreviation consts c;
val rev_abbrevs' = rev_abbrevs
|> fold (curry Symtab.cons_list mode) (rev_abbrev (Const (c, T)) rhs);
in (decls, constraints, rev_abbrevs') end);
end;
(* empty and merge *)
val empty = make_consts (NameSpace.empty_table, Symtab.empty, Symtab.empty);
fun merge
(Consts ({decls = decls1, constraints = constraints1, rev_abbrevs = rev_abbrevs1}, _),
Consts ({decls = decls2, constraints = constraints2, rev_abbrevs = rev_abbrevs2}, _)) =
let
val decls' = NameSpace.merge_tables (eq_snd (op =)) (decls1, decls2)
handle Symtab.DUP c => err_dup_const c;
val constraints' = Symtab.join (K fst) (constraints1, constraints2);
val rev_abbrevs' = (rev_abbrevs1, rev_abbrevs2) |> Symtab.join
(K (Library.merge (fn ((t, u), (t', u')) => t aconv t' andalso u aconv u')));
in make_consts (decls', constraints', rev_abbrevs') end;
end;