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(************************************************************************)
(* v * The Coq Proof Assistant / The Coq Development Team *)
(* <O___,, * INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2010 *)
(* \VV/ **************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(************************************************************************)
Require Import List.
Require Import Setoid.
Require Import BinPos.
Require Import BinList.
Require Import Znumtheory.
Require Export Morphisms Setoid Bool.
Require Import ZArith.
Open Scope Z_scope.
Require Import Algebra_syntax.
Require Export Ring2.
Require Import Ring2_polynom.
Require Import Ring2_initial.
Set Implicit Arguments.
(* Reification with Type Classes, inspired from B.Grégoire and A.Spiewack *)
Class is_in_list_at (R:Type) (t:R) (l:list R) (i:nat) := {}.
Instance Ifind0 (R:Type) (t:R) l
: is_in_list_at t (t::l) 0.
Instance IfindS (R:Type) (t2 t1:R) l i
`{is_in_list_at R t1 l i}
: is_in_list_at t1 (t2::l) (S i) | 1.
Class reifyPE (R:Type) (e:PExpr Z) (lvar:list R) (t:R) := {}.
Instance reify_zero (R:Type) (RR:Ring R) lvar
: reifyPE (PEc 0%Z) lvar ring0.
Instance reify_one (R:Type) (RR:Ring R) lvar
: reifyPE (PEc 1%Z) lvar ring1.
Instance reify_plus (R:Type) (RR:Ring R)
e1 lvar t1 e2 t2
`{reifyPE R e1 lvar t1}
`{reifyPE R e2 lvar t2}
: reifyPE (PEadd e1 e2) lvar (ring_plus t1 t2).
Instance reify_mult (R:Type) (RR:Ring R)
e1 lvar t1 e2 t2
`{reifyPE R e1 lvar t1}
`{reifyPE R e2 lvar t2}
: reifyPE (PEmul e1 e2) lvar (ring_mult t1 t2).
Instance reify_sub (R:Type) (RR:Ring R)
e1 lvar t1 e2 t2
`{reifyPE R e1 lvar t1}
`{reifyPE R e2 lvar t2}
: reifyPE (PEsub e1 e2) lvar (ring_sub t1 t2).
Instance reify_opp (R:Type) (RR:Ring R)
e1 lvar t1
`{reifyPE R e1 lvar t1}
: reifyPE (PEopp e1) lvar (ring_opp t1).
Instance reify_var (R:Type) t lvar i
`{is_in_list_at R t lvar i}
: reifyPE (PEX Z (P_of_succ_nat i)) lvar t
| 100.
Class reifyPElist (R:Type) (lexpr:list (PExpr Z)) (lvar:list R)
(lterm:list R) := {}.
Instance reifyPE_nil (R:Type) lvar
: @reifyPElist R nil lvar (@nil R).
Instance reifyPE_cons (R:Type) e1 lvar t1 lexpr2 lterm2
`{reifyPE R e1 lvar t1} `{reifyPElist R lexpr2 lvar lterm2}
: reifyPElist (e1::lexpr2) lvar (t1::lterm2).
Class is_closed_list T (l:list T) := {}.
Instance Iclosed_nil T
: is_closed_list (T:=T) nil.
Instance Iclosed_cons T t l
`{is_closed_list (T:=T) l}
: is_closed_list (T:=T) (t::l).
Definition list_reifyl (R:Type) lexpr lvar lterm
`{reifyPElist R lexpr lvar lterm}
`{is_closed_list (T:=R) lvar} := (lvar,lexpr).
Unset Implicit Arguments.
Instance multiplication_phi_ring{R:Type}{Rr:Ring R} : Multiplication :=
{multiplication x y := ring_mult (gen_phiZ Rr x) y}.
(*
Print HintDb typeclass_instances.
*)
(* Reification *)
Ltac lterm_goal g :=
match g with
ring_eq ?t1 ?t2 => constr:(t1::t2::nil)
| ring_eq ?t1 ?t2 -> ?g => let lvar :=
lterm_goal g in constr:(t1::t2::lvar)
end.
Ltac reify_goal lvar lexpr lterm:=
(* idtac lvar; idtac lexpr; idtac lterm;*)
match lexpr with
nil => idtac
| ?e::?lexpr1 =>
match lterm with
?t::?lterm1 => (* idtac "t="; idtac t;*)
let x := fresh "T" in
set (x:= t);
change x with
(@PEeval Z Zr _ _ (@gen_phiZ_morph _ _) N
(fun n:N => n) (@Ring_theory.pow_N _ ring1 ring_mult)
lvar e);
clear x;
reify_goal lvar lexpr1 lterm1
end
end.
Existing Instance gen_phiZ_morph.
Existing Instance Zr.
Lemma comm: forall (R:Type)(Rr:Ring R)(c : Z) (x : R),
x * [c] == [c] * x.
induction c. intros. ring_simpl. gen_ring_rewrite. simpl. intros.
ring_rewrite_rev same_gen.
induction p. simpl. gen_ring_rewrite. ring_rewrite IHp. rrefl.
simpl. gen_ring_rewrite. ring_rewrite IHp. rrefl.
simpl. gen_ring_rewrite.
simpl. intros. ring_rewrite_rev same_gen.
induction p. simpl. generalize IHp. clear IHp.
gen_ring_rewrite. intro IHp. ring_rewrite IHp. rrefl.
simpl. generalize IHp. clear IHp.
gen_ring_rewrite. intro IHp. ring_rewrite IHp. rrefl.
simpl. gen_ring_rewrite. Qed.
Lemma Zeqb_ok: forall x y : Z, Zeq_bool x y = true -> x == y.
intros x y H. rewrite (Zeq_bool_eq x y H). rrefl. Qed.
Ltac ring_gen :=
match goal with
|- ?g => let lterm := lterm_goal g in (* les variables *)
match eval red in (list_reifyl (lterm:=lterm)) with
| (?fv, ?lexpr) =>
(* idtac "variables:";idtac fv;
idtac "terms:"; idtac lterm;
idtac "reifications:"; idtac lexpr;
*)
reify_goal fv lexpr lterm;
match goal with
|- ?g =>
set_ring_notations;
apply (@ring_correct Z Zr _ _ (@gen_phiZ_morph _ _)
(@comm _ _) Zeq_bool Zeqb_ok N (fun n:N => n)
(@Ring_theory.pow_N _ 1 multiplication));
[apply mkpow_th; rrefl
|vm_compute; reflexivity]
end
end
end.
(* Pierre L: these tests should be done in a section, otherwise
global axioms are generated. Ideally such tests should go in
the test-suite directory *)
Section Tests.
Ltac ring2:=
unset_ring_notations; intros;
match goal with
|- (@ring_eq ?r ?rd _ _ ) =>
simpl; ring_gen
end.
Variable R: Type.
Variable Rr: Ring R.
Existing Instance Rr.
Goal forall x y z:R, x == x .
ring2.
Qed.
Goal forall x y z:R, x * y * z == x * (y * z).
ring2.
Qed.
Goal forall x y z:R, [3]* x *([2]* y * z) == [6] * (x * y) * z.
ring2.
Qed.
Goal forall x y z:R, 3 * x * (2 * y * z) == 6 * (x * y) * z.
ring2.
Qed.
(* Fails with Multiplication: A -> B -> C.
Goal forall x:R, 2%Z * (x * x) == 3%Z * x.
Admitted.
*)
End Tests.
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