(* Title: HOL/Tools/Predicate_Compile/predicate_compile_specialisation.ML
Author: Lukas Bulwahn, TU Muenchen
Deriving specialised predicates and their intro rules
*)
signature PREDICATE_COMPILE_SPECIALISATION =
sig
val find_specialisations : string list -> (string * thm list) list -> theory -> (string * thm list) list * theory
end;
structure Predicate_Compile_Specialisation : PREDICATE_COMPILE_SPECIALISATION =
struct
open Predicate_Compile_Aux;
(* table of specialisations *)
structure Specialisations = Theory_Data
(
type T = (term * term) Item_Net.T;
val empty : T = Item_Net.init (op aconv o pairself fst) (single o fst);
val extend = I;
val merge = Item_Net.merge;
)
fun specialisation_of thy atom =
Item_Net.retrieve (Specialisations.get thy) atom
fun print_specialisations thy =
tracing (cat_lines (map (fn (t, spec_t) =>
Syntax.string_of_term_global thy t ^ " ~~~> " ^ Syntax.string_of_term_global thy spec_t)
(Item_Net.content (Specialisations.get thy))))
fun import (pred, intros) args ctxt =
let
val thy = ProofContext.theory_of ctxt
val ((Tinst, intros'), ctxt') = Variable.importT intros ctxt
val pred' = fst (strip_comb (HOLogic.dest_Trueprop (Logic.strip_imp_concl (prop_of (hd intros')))))
val Ts = binder_types (fastype_of pred')
val argTs = map fastype_of args
val Tsubst = Type.raw_matches (argTs, Ts) Vartab.empty
val args' = map (Envir.subst_term_types Tsubst) args
in
(((pred', intros'), args'), ctxt')
end
(* patterns only constructed of variables and pairs/tuples are trivial constructor terms*)
fun is_nontrivial_constrt thy t =
let
val cnstrs = flat (maps
(map (fn (_, (Tname, _, cs)) => map (apsnd (rpair Tname o length)) cs) o #descr o snd)
(Symtab.dest (Datatype.get_all thy)));
fun check t = (case strip_comb t of
(Var _, []) => (true, true)
| (Free _, []) => (true, true)
| (Const (@{const_name Pair}, _), ts) =>
pairself (forall I) (split_list (map check ts))
| (Const (s, T), ts) => (case (AList.lookup (op =) cnstrs s, body_type T) of
(SOME (i, Tname), Type (Tname', _)) => (false,
length ts = i andalso Tname = Tname' andalso forall (snd o check) ts)
| _ => (false, false))
| _ => (false, false))
in check t = (false, true) end;
fun specialise_intros black_list (pred, intros) pats thy =
let
val ctxt = ProofContext.init_global thy
val maxidx = fold (Term.maxidx_term o prop_of) intros ~1
val pats = map (Logic.incr_indexes ([], maxidx + 1)) pats
val (((pred, intros), pats), ctxt') = import (pred, intros) pats ctxt
val intros_t = map prop_of intros
val result_pats = map Var (fold_rev Term.add_vars pats [])
fun mk_fresh_name names =
let
val name =
Name.variant names ("specialised_" ^ Long_Name.base_name (fst (dest_Const pred)))
val bname = Sign.full_bname thy name
in
if Sign.declared_const thy bname then
mk_fresh_name (name :: names)
else
bname
end
val constname = mk_fresh_name []
val constT = map fastype_of result_pats ---> @{typ bool}
val specialised_const = Const (constname, constT)
val specialisation =
[(HOLogic.mk_Trueprop (list_comb (pred, pats)),
HOLogic.mk_Trueprop (list_comb (specialised_const, result_pats)))]
fun specialise_intro intro =
(let
val (prems, concl) = Logic.strip_horn (prop_of intro)
val env = Pattern.unify thy
(HOLogic.mk_Trueprop (list_comb (pred, pats)), concl) (Envir.empty 0)
val prems = map (Envir.norm_term env) prems
val args = map (Envir.norm_term env) result_pats
val concl = HOLogic.mk_Trueprop (list_comb (specialised_const, args))
val intro = Logic.list_implies (prems, concl)
in
SOME intro
end handle Pattern.Unif => NONE)
val specialised_intros_t = map_filter I (map specialise_intro intros)
val thy' = Sign.add_consts_i [(Binding.name (Long_Name.base_name constname), constT, NoSyn)] thy
val specialised_intros = map (Skip_Proof.make_thm thy') specialised_intros_t
val exported_intros = Variable.exportT ctxt' ctxt specialised_intros
val [t, specialised_t] = Variable.exportT_terms ctxt' ctxt
[list_comb (pred, pats), list_comb (specialised_const, result_pats)]
val thy'' = Specialisations.map (Item_Net.update (t, specialised_t)) thy'
val optimised_intros =
map_filter (Predicate_Compile_Aux.peephole_optimisation thy'') exported_intros
val ([spec], thy''') = find_specialisations black_list [(constname, optimised_intros)] thy''
val thy'''' = Predicate_Compile_Core.register_intros spec thy'''
in
thy''''
end
and find_specialisations black_list specs thy =
let
val add_vars = fold_aterms (fn Var v => cons v | _ => I);
fun fresh_free T free_names =
let
val free_name = Name.variant free_names "x"
in
(Free (free_name, T), free_name :: free_names)
end
fun replace_term_and_restrict thy T t Tts free_names =
let
val (free, free_names') = fresh_free T free_names
val Tts' = map (apsnd (Pattern.rewrite_term thy [(t, free)] [])) Tts
val (ts', free_names'') = restrict_pattern' thy Tts' free_names'
in
(free :: ts', free_names'')
end
and restrict_pattern' thy [] free_names = ([], free_names)
| restrict_pattern' thy ((T, Free (x, _)) :: Tts) free_names =
let
val (ts', free_names') = restrict_pattern' thy Tts free_names
in
(Free (x, T) :: ts', free_names')
end
| restrict_pattern' thy ((T as TFree _, t) :: Tts) free_names =
replace_term_and_restrict thy T t Tts free_names
| restrict_pattern' thy ((T as Type (Tcon, Ts), t) :: Tts) free_names =
case Datatype_Data.get_constrs thy Tcon of
NONE => replace_term_and_restrict thy T t Tts free_names
| SOME constrs => (case strip_comb t of
(Const (s, _), ats) => (case AList.lookup (op =) constrs s of
SOME constr_T =>
let
val (Ts', T') = strip_type constr_T
val Tsubst = Type.raw_match (T', T) Vartab.empty
val Ts = map (Envir.subst_type Tsubst) Ts'
val (bts', free_names') = restrict_pattern' thy ((Ts ~~ ats) @ Tts) free_names
val (ats', ts') = chop (length ats) bts'
in
(list_comb (Const (s, map fastype_of ats' ---> T), ats') :: ts', free_names')
end
| NONE => replace_term_and_restrict thy T t Tts free_names))
fun restrict_pattern thy Ts args =
let
val args = map Logic.unvarify_global args
val Ts = map Logic.unvarifyT_global Ts
val free_names = fold Term.add_free_names args []
val (pat, _) = restrict_pattern' thy (Ts ~~ args) free_names
in map Logic.varify_global pat end
fun detect' atom thy =
case strip_comb atom of
(pred as Const (pred_name, _), args) =>
let
val Ts = binder_types (Sign.the_const_type thy pred_name)
val vnames = map fst (fold Term.add_var_names args [])
val pats = restrict_pattern thy Ts args
in
if (exists (is_nontrivial_constrt thy) pats)
orelse (has_duplicates (op =) (fold add_vars pats [])) then
let
val thy' =
case specialisation_of thy atom of
[] =>
if member (op =) ((map fst specs) @ black_list) pred_name then
thy
else
(case try (Predicate_Compile_Core.intros_of (ProofContext.init_global thy)) pred_name of
NONE => thy
| SOME [] => thy
| SOME intros =>
specialise_intros ((map fst specs) @ (pred_name :: black_list))
(pred, intros) pats thy)
| (t, specialised_t) :: _ => thy
val atom' =
case specialisation_of thy' atom of
[] => atom
| (t, specialised_t) :: _ =>
let
val subst = Pattern.match thy' (t, atom) (Vartab.empty, Vartab.empty)
in Envir.subst_term subst specialised_t end handle Pattern.MATCH => atom
(*FIXME: this exception could be caught earlier in specialisation_of *)
in
(atom', thy')
end
else (atom, thy)
end
| _ => (atom, thy)
fun specialise' (constname, intros) thy =
let
(* FIXME: only necessary because of sloppy Logic.unvarify in restrict_pattern *)
val intros = Drule.zero_var_indexes_list intros
val (intros_t', thy') = (fold_map o fold_map_atoms) detect' (map prop_of intros) thy
in
((constname, map (Skip_Proof.make_thm thy') intros_t'), thy')
end
in
fold_map specialise' specs thy
end
end;