author | wenzelm |
Fri, 28 Dec 2018 16:58:27 +0100 | |
changeset 69524 | fa94f2b2a877 |
parent 56025 | d74fed45fa8b |
child 77821 | d1d28b36ba59 |
permissions | -rw-r--r-- |
43796 | 1 |
(* Title: Pure/term_sharing.ML |
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Author: Makarius |
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Local sharing of type/term sub-structure, with global interning of |
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formal entity names. |
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*) |
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signature TERM_SHARING = |
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sig |
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val init: theory -> (typ -> typ) * (term -> term) |
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val typs: theory -> typ list -> typ list |
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val terms: theory -> term list -> term list |
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end; |
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structure Term_Sharing: TERM_SHARING = |
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struct |
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structure Syntax_Termtab = Table(type key = term val ord = Term_Ord.syntax_term_ord); |
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fun init thy = |
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let |
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val {classes = (_, algebra), types, ...} = Type.rep_tsig (Sign.tsig_of thy); |
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val class = perhaps (try (#1 o Graph.get_entry (Sorts.classes_of algebra))); |
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val tycon = perhaps (Option.map #1 o Name_Space.lookup_key types); |
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val const = perhaps (try (#1 o Consts.the_const (Sign.consts_of thy))); |
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val typs = Unsynchronized.ref (Typtab.empty: unit Typtab.table); |
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val terms = Unsynchronized.ref (Syntax_Termtab.empty: unit Syntax_Termtab.table); |
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fun typ T = |
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(case Typtab.lookup_key (! typs) T of |
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SOME (T', ()) => T' |
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| NONE => |
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let |
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val T' = |
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(case T of |
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Type (a, Ts) => Type (tycon a, map typ Ts) |
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| TFree (a, S) => TFree (a, map class S) |
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| TVar (a, S) => TVar (a, map class S)); |
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val _ = Unsynchronized.change typs (Typtab.update (T', ())); |
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in T' end); |
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fun term tm = |
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(case Syntax_Termtab.lookup_key (! terms) tm of |
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SOME (tm', ()) => tm' |
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| NONE => |
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let |
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val tm' = |
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(case tm of |
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Const (c, T) => Const (const c, typ T) |
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| Free (x, T) => Free (x, typ T) |
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| Var (xi, T) => Var (xi, typ T) |
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| Bound i => Bound i |
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| Abs (x, T, t) => Abs (x, typ T, term t) |
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| t $ u => term t $ term u); |
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val _ = Unsynchronized.change terms (Syntax_Termtab.update (tm', ())); |
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in tm' end); |
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||
43950
49f0e4ae2350
defensive Term_Sharing, to avoid extending trusted code base of inference kernel;
wenzelm
parents:
43796
diff
changeset
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fun check eq f x = |
49f0e4ae2350
defensive Term_Sharing, to avoid extending trusted code base of inference kernel;
wenzelm
parents:
43796
diff
changeset
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let val x' = f x in |
49f0e4ae2350
defensive Term_Sharing, to avoid extending trusted code base of inference kernel;
wenzelm
parents:
43796
diff
changeset
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if eq (x, x') then x' |
49f0e4ae2350
defensive Term_Sharing, to avoid extending trusted code base of inference kernel;
wenzelm
parents:
43796
diff
changeset
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else raise Fail "Something is utterly wrong" |
49f0e4ae2350
defensive Term_Sharing, to avoid extending trusted code base of inference kernel;
wenzelm
parents:
43796
diff
changeset
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end; |
49f0e4ae2350
defensive Term_Sharing, to avoid extending trusted code base of inference kernel;
wenzelm
parents:
43796
diff
changeset
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|
49f0e4ae2350
defensive Term_Sharing, to avoid extending trusted code base of inference kernel;
wenzelm
parents:
43796
diff
changeset
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in (check (op =) typ, check (op =) term) end; |
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val typs = map o #1 o init; |
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val terms = map o #2 o init; |
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end; |
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