(* Title: Pure/consts.ML
Author: Makarius
Polymorphic constants: declarations, abbreviations, additional type
constraints.
*)
signature CONSTS =
sig
type T
val eq_consts: T * T -> bool
val change_base: bool -> T -> T
val change_ignore: T -> T
val retrieve_abbrevs: T -> string list -> term -> (term * term) list
val dest: T ->
{const_space: Name_Space.T,
constants: (string * (typ * term option)) list,
constraints: (string * typ) list}
val the_const: T -> string -> string * typ (*exception TYPE*)
val the_abbreviation: T -> string -> typ * term (*exception TYPE*)
val type_scheme: T -> string -> typ (*exception TYPE*)
val is_monomorphic: T -> string -> bool (*exception TYPE*)
val the_constraint: T -> string -> typ (*exception TYPE*)
val space_of: T -> Name_Space.T
val alias: Name_Space.naming -> binding -> string -> T -> T
val is_concealed: T -> string -> bool
val intern: T -> xstring -> string
val intern_syntax: T -> xstring -> string
val check_const: Context.generic -> T -> xstring * Position.T list -> term * Position.report list
val certify: Context.generic -> Type.tsig -> bool -> T -> term -> term (*exception TYPE*)
val typargs: T -> string * typ -> typ list
val instance: T -> string * typ list -> typ
val declare: Context.generic -> binding * typ -> T -> T
val constrain: string * typ option -> T -> T
val abbreviate: Context.generic -> Type.tsig -> string -> binding * 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};
type abbrev = {rhs: term, normal_rhs: term, force_expand: bool};
datatype T = Consts of
{decls: (decl * abbrev option) Name_Space.table,
constraints: typ Symtab.table,
rev_abbrevs: (term * term) Item_Net.T Symtab.table};
fun eq_consts
(Consts {decls = decls1, constraints = constraints1, rev_abbrevs = rev_abbrevs1},
Consts {decls = decls2, constraints = constraints2, rev_abbrevs = rev_abbrevs2}) =
pointer_eq (decls1, decls2) andalso
pointer_eq (constraints1, constraints2) andalso
pointer_eq (rev_abbrevs1, rev_abbrevs2);
fun make_consts (decls, constraints, rev_abbrevs) =
Consts {decls = decls, constraints = constraints, rev_abbrevs = rev_abbrevs};
fun map_consts f (Consts {decls, constraints, rev_abbrevs}) =
make_consts (f (decls, constraints, rev_abbrevs));
fun change_base begin = map_consts (fn (decls, constraints, rev_abbrevs) =>
(Name_Space.change_base begin decls, constraints, rev_abbrevs));
val change_ignore = map_consts (fn (decls, constraints, rev_abbrevs) =>
(Name_Space.change_ignore decls, constraints, rev_abbrevs));
(* reverted abbrevs *)
val empty_abbrevs =
Item_Net.init (fn ((t, u), (t', u')) => t aconv t' andalso u aconv u') (single o #1);
fun update_abbrevs mode abbrs =
Symtab.map_default (mode, empty_abbrevs) (Item_Net.update abbrs);
fun retrieve_abbrevs (Consts {rev_abbrevs, ...}) modes =
let val nets = map_filter (Symtab.lookup rev_abbrevs) modes in
fn t =>
let
val retrieve =
if Term.could_beta_eta_contract t
then Item_Net.retrieve
else Item_Net.retrieve_matching
in maps (fn net => retrieve net t) nets end
end;
(* dest consts *)
fun dest (Consts {decls, constraints, ...}) =
{const_space = Name_Space.space_of_table decls,
constants =
Name_Space.fold_table (fn (c, ({T, ...}, abbr)) =>
cons (c, (T, Option.map #rhs abbr))) decls [],
constraints = Symtab.dest constraints};
(* lookup consts *)
fun the_entry (Consts {decls, ...}) c =
(case Name_Space.lookup_key decls c of
SOME entry => entry
| NONE => raise TYPE ("Unknown constant: " ^ quote c, [], []));
fun the_const consts c =
(case the_entry consts c of
(c', ({T, ...}, NONE)) => (c', T)
| _ => raise TYPE ("Not a logical constant: " ^ quote c, [], []));
fun the_abbreviation consts c =
(case the_entry consts c of
(_, ({T, ...}, SOME {rhs, ...})) => (T, rhs)
| _ => raise TYPE ("Not an abbreviated constant: " ^ quote c, [], []));
fun the_decl consts = #1 o #2 o the_entry consts;
val type_scheme = #T oo the_decl;
val type_arguments = #typargs 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, ...}) = Name_Space.space_of_table decls;
fun alias naming binding name = map_consts (fn (decls, constraints, rev_abbrevs) =>
((Name_Space.alias_table naming binding name decls), constraints, rev_abbrevs));
val is_concealed = Name_Space.is_concealed o space_of;
val intern = Name_Space.intern o space_of;
fun intern_syntax consts s =
(case try Lexicon.unmark_const s of
SOME c => c
| NONE => intern consts s);
(* check_const *)
fun check_const context consts (xname, ps) =
let
val Consts {decls, ...} = consts;
val ((c, reports), _) = Name_Space.check_reports context decls (xname, ps);
val T = type_scheme consts c handle TYPE (msg, _, _) => error (msg ^ Position.here_list ps);
in (Const (c, T), reports) end;
(* certify *)
fun certify context tsig do_expand consts =
let
fun err msg (c, T) =
raise TYPE (msg ^ " " ^ quote c ^ " :: " ^
Syntax.string_of_typ (Syntax.init_pretty context) 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_entry 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 _ _ = 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 ListPair.UnequalLengths =>
raise TYPE ("Consts.instance", Ts, [Const (c, dummyT)]);
in declT |> Term_Subst.instantiateT inst end;
(** build consts **)
(* name space *)
fun hide fully c = map_consts (fn (decls, constraints, rev_abbrevs) =>
(Name_Space.hide_table fully c decls, constraints, rev_abbrevs));
(* declarations *)
fun declare context (b, declT) =
map_consts (fn (decls, constraints, rev_abbrevs) =>
let
val decl = {T = declT, typargs = typargs_of declT};
val _ = Binding.check b;
val (_, decls') = decls |> Name_Space.define context true (b, (decl, NONE));
in (decls', constraints, rev_abbrevs) end);
(* constraints *)
fun constrain (c, C) consts =
consts |> map_consts (fn (decls, constraints, rev_abbrevs) =>
(#2 (the_entry 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 (t as Abs (x, T, b)) =
if Term.is_dependent b then strip_abss b |>> cons (x, T) (* FIXME decr!? *)
else ([], t)
| strip_abss t = ([], t);
fun rev_abbrev lhs rhs =
let
val (xs, body) = strip_abss (Envir.beta_eta_contract rhs);
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
fun abbreviate context tsig mode (b, raw_rhs) consts =
let
val cert_term = certify context tsig false consts;
val expand_term = certify context tsig true consts;
val force_expand = mode = Print_Mode.internal;
val _ = Term.exists_subterm Term.is_Var raw_rhs andalso
error ("Illegal schematic variables on rhs of abbreviation " ^ Binding.print b);
val rhs = raw_rhs
|> Term.map_types (Type.cert_typ tsig)
|> cert_term
|> Term.close_schematic_term;
val normal_rhs = expand_term rhs;
val T = Term.fastype_of rhs;
val lhs = Const (Name_Space.full_name (Name_Space.naming_of context) b, T);
in
consts |> map_consts (fn (decls, constraints, rev_abbrevs) =>
let
val decl = {T = T, typargs = typargs_of T};
val abbr = {rhs = rhs, normal_rhs = normal_rhs, force_expand = force_expand};
val _ = Binding.check b;
val (_, decls') = decls
|> Name_Space.define context true (b, (decl, SOME abbr));
val rev_abbrevs' = rev_abbrevs
|> update_abbrevs 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
|> update_abbrevs mode (rev_abbrev (Const (c, T)) rhs);
in (decls, constraints, rev_abbrevs') end);
end;
(* empty and merge *)
val empty =
make_consts (Name_Space.empty_table Markup.constantN, 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' = Name_Space.merge_tables (decls1, decls2);
val constraints' = Symtab.merge (K true) (constraints1, constraints2);
val rev_abbrevs' = Symtab.join (K Item_Net.merge) (rev_abbrevs1, rev_abbrevs2);
in make_consts (decls', constraints', rev_abbrevs') end;
end;