# LibTacticsA Collection of Handy General-Purpose Tactics

(* Chapter maintained by Arthur Chargueraud *)

This file contains a set of tactics that extends the set of builtin tactics provided with the standard distribution of Coq. It intends to overcome a number of limitations of the standard set of tactics, and thereby to help user to write shorter and more robust scripts.
Hopefully, Coq tactics will be improved as time goes by, and this file should ultimately be useless. In the meanwhile, serious Coq users will probably find it very useful.
The present file contains the implementation and the detailed documentation of those tactics. The SF reader need not read this file; instead, he/she is encouraged to read the chapter named UseTactics.v, which is gentle introduction to the most useful tactics from the LibTactic library.
The main features offered are:
• More convenient syntax for naming hypotheses, with tactics for introduction and inversion that take as input only the name of hypotheses of type Prop, rather than the name of all variables.
• Tactics providing true support for manipulating N-ary conjunctions, disjunctions and existentials, hidding the fact that the underlying implementation is based on binary propositions.
• Convenient support for automation: tactic followed with the symbol "~" or "*" will call automation on the generated subgoals. Symbol "~" stands for auto and "*" for intuition eauto. These bindings can be customized.
• Forward-chaining tactics are provided to instantiate lemmas either with variable or hypotheses or a mix of both.
• A more powerful implementation of apply is provided (it is based on refine and thus behaves better with respect to conversion).
• An improved inversion tactic which substitutes equalities on variables generated by the standard inversion mecanism. Moreover, it supports the elimination of dependently-typed equalities (requires axiom K, which is a weak form of Proof Irrelevance).
• Tactics for saving time when writing proofs, with tactics to asserts hypotheses or sub-goals, and improved tactics for clearing, renaming, and sorting hypotheses.
External credits:
• thanks to Xavier Leroy for providing the idea of tactic forward,
• thanks to Georges Gonthier for the implementation trick in rapply,

Set Implicit Arguments.

Require Import List.

(* Very important to remove hint trans_eq_bool from LibBool,
otherwise eauto slows down dramatically:
Lemma test : forall b, b = false.
time eauto 7. (* takes over 4 seconds  to fail! *) *)

Remove Hints Bool.trans_eq_bool.

(* ********************************************************************** *)

# Tools for programming with Ltac

(* ---------------------------------------------------------------------- *)

## Identity continuation

Ltac idcont tt :=
idtac.

(* ---------------------------------------------------------------------- *)

## Untyped arguments for tactics

Any Coq value can be boxed into the type Boxer. This is useful to use Coq computations for implementing tactics.

Inductive Boxer : Type :=
| boxer : (A:Type), A Boxer.

(* ---------------------------------------------------------------------- *)

## Optional arguments for tactics

ltac_no_arg is a constant that can be used to simulate optional arguments in tactic definitions. Use mytactic ltac_no_arg on the tactic invokation, and use match arg with ltac_no_arg .. or match type of arg with ltac_No_arg .. to test whether an argument was provided.

Inductive ltac_No_arg : Set :=
| ltac_no_arg : ltac_No_arg.

(* ---------------------------------------------------------------------- *)

## Wildcard arguments for tactics

ltac_wild is a constant that can be used to simulate wildcard arguments in tactic definitions. Notation is __.

Inductive ltac_Wild : Set :=
| ltac_wild : ltac_Wild.

Notation "'__'" := ltac_wild : ltac_scope.

ltac_wilds is another constant that is typically used to simulate a sequence of N wildcards, with N chosen appropriately depending on the context. Notation is ___.

Inductive ltac_Wilds : Set :=
| ltac_wilds : ltac_Wilds.

Notation "'___'" := ltac_wilds : ltac_scope.

Open Scope ltac_scope.

(* ---------------------------------------------------------------------- *)

## Position markers

ltac_Mark and ltac_mark are dummy definitions used as sentinel by tactics, to mark a certain position in the context or in the goal.

Inductive ltac_Mark : Type :=
| ltac_mark : ltac_Mark.

gen_until_mark repeats generalize on hypotheses from the context, starting from the bottom and stopping as soon as reaching an hypothesis of type Mark. If fails if Mark does not appear in the context.

Ltac gen_until_mark :=
match goal with H: ?T _
match T with
| ltac_Markclear H
| _generalize H; clear H; gen_until_mark
end end.

intro_until_mark repeats intro until reaching an hypothesis of type Mark. It throws away the hypothesis Mark. It fails if Mark does not appear as an hypothesis in the goal.

Ltac intro_until_mark :=
match goal with
| (ltac_Mark _) ⇒ intros _
| _intro; intro_until_mark
end.

(* ---------------------------------------------------------------------- *)

## List of arguments for tactics

A datatype of type list Boxer is used to manipulate list of Coq values in ltac. Notation is >> v1 v2 ... vN for building a list containing the values v1 through vN.

Notation "'>>'" :=
(@nil Boxer)
(at level 0)
: ltac_scope.
Notation "'>>' v1" :=
((boxer v1)::nil)
(at level 0, v1 at level 0)
: ltac_scope.
Notation "'>>' v1 v2" :=
((boxer v1)::(boxer v2)::nil)
(at level 0, v1 at level 0, v2 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3" :=
((boxer v1)::(boxer v2)::(boxer v3)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5 v6" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)
::(boxer v6)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0, v6 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5 v6 v7" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)
::(boxer v6)::(boxer v7)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0, v6 at level 0, v7 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5 v6 v7 v8" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)
::(boxer v6)::(boxer v7)::(boxer v8)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0, v6 at level 0, v7 at level 0,
v8 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5 v6 v7 v8 v9" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)
::(boxer v6)::(boxer v7)::(boxer v8)::(boxer v9)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0, v6 at level 0, v7 at level 0,
v8 at level 0, v9 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5 v6 v7 v8 v9 v10" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)
::(boxer v6)::(boxer v7)::(boxer v8)::(boxer v9)::(boxer v10)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0, v6 at level 0, v7 at level 0,
v8 at level 0, v9 at level 0, v10 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5 v6 v7 v8 v9 v10 v11" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)
::(boxer v6)::(boxer v7)::(boxer v8)::(boxer v9)::(boxer v10)
::(boxer v11)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0, v6 at level 0, v7 at level 0,
v8 at level 0, v9 at level 0, v10 at level 0, v11 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5 v6 v7 v8 v9 v10 v11 v12" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)
::(boxer v6)::(boxer v7)::(boxer v8)::(boxer v9)::(boxer v10)
::(boxer v11)::(boxer v12)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0, v6 at level 0, v7 at level 0,
v8 at level 0, v9 at level 0, v10 at level 0, v11 at level 0,
v12 at level 0)
: ltac_scope.
Notation "'>>' v1 v2 v3 v4 v5 v6 v7 v8 v9 v10 v11 v12 v13" :=
((boxer v1)::(boxer v2)::(boxer v3)::(boxer v4)::(boxer v5)
::(boxer v6)::(boxer v7)::(boxer v8)::(boxer v9)::(boxer v10)
::(boxer v11)::(boxer v12)::(boxer v13)::nil)
(at level 0, v1 at level 0, v2 at level 0, v3 at level 0,
v4 at level 0, v5 at level 0, v6 at level 0, v7 at level 0,
v8 at level 0, v9 at level 0, v10 at level 0, v11 at level 0,
v12 at level 0, v13 at level 0)
: ltac_scope.

The tactic list_boxer_of inputs a term E and returns a term of type "list boxer", according to the following rules:
• if E is already of type "list Boxer", then it returns E;
• otherwise, it returns the list (boxer E)::nil.

Ltac list_boxer_of E :=
match type of E with
| List.list Boxerconstr:(E)
| _constr:((boxer E)::nil)
end.

(* ---------------------------------------------------------------------- *)

## Databases of lemmas

Use the hint facility to implement a database mapping terms to terms. To declare a new database, use a definition: Definition mydatabase := True.
Then, to map mykey to myvalue, write the hint: Hint Extern 1 (Register mydatabase mykey) Provide myvalue.
Finally, to query the value associated with a key, run the tactic ltac_database_get mydatabase mykey. This will leave at the head of the goal the term myvalue. It can then be named and exploited using intro.

Inductive Ltac_database_token : Prop := ltac_database_token.

Definition ltac_database (D:Boxer) (T:Boxer) (A:Boxer) := Ltac_database_token.

Notation "'Register' D T" := (ltac_database (boxer D) (boxer T) _)
(at level 69, D at level 0, T at level 0).

Lemma ltac_database_provide : (A:Boxer) (D:Boxer) (T:Boxer),
ltac_database D T A.
Proof using. split. Qed.

Ltac Provide T := apply (@ltac_database_provide (boxer T)).

Ltac ltac_database_get D T :=
let A := fresh "TEMP" in evar (A:Boxer);
let H := fresh "TEMP" in
assert (H : ltac_database (boxer D) (boxer T) A);
[ subst A; auto
| subst A; match type of H with ltac_database _ _ (boxer ?L) ⇒
generalize L end; clear H ].

(* Note for a possible alternative implementation of the ltac_database_token:
Inductive Ltac_database : Type :=
| ltac_database : forall A, A -> Ltac_database.
Implicit Arguments ltac_database A.
*)

(* ---------------------------------------------------------------------- *)

## On-the-fly removal of hypotheses

In a list of arguments >> H1 H2 .. HN passed to a tactic such as lets or applys or forwards or specializes, the term rm, an identity function, can be placed in front of the name of an hypothesis to be deleted.

Definition rm (A:Type) (X:A) := X.

rm_term E removes one hypothesis that admits the same type as E.

Ltac rm_term E :=
let T := type of E in
match goal with H: T _try clear H end.

rm_inside E calls rm_term Ei for any subterm of the form rm Ei found in E

Ltac rm_inside E :=
let go E := rm_inside E in
match E with
| rm ?Xrm_term X
| ?X1 ?X2
go X1; go X2
| ?X1 ?X2 ?X3
go X1; go X2; go X3
| ?X1 ?X2 ?X3 ?X4
go X1; go X2; go X3; go X4
| ?X1 ?X2 ?X3 ?X4 ?X5
go X1; go X2; go X3; go X4; go X5
| ?X1 ?X2 ?X3 ?X4 ?X5 ?X6
go X1; go X2; go X3; go X4; go X5; go X6
| ?X1 ?X2 ?X3 ?X4 ?X5 ?X6 ?X7
go X1; go X2; go X3; go X4; go X5; go X6; go X7
| ?X1 ?X2 ?X3 ?X4 ?X5 ?X6 ?X7 ?X8
go X1; go X2; go X3; go X4; go X5; go X6; go X7; go X8
| ?X1 ?X2 ?X3 ?X4 ?X5 ?X6 ?X7 ?X8 ?X9
go X1; go X2; go X3; go X4; go X5; go X6; go X7; go X8; go X9
| ?X1 ?X2 ?X3 ?X4 ?X5 ?X6 ?X7 ?X8 ?X9 ?X10
go X1; go X2; go X3; go X4; go X5; go X6; go X7; go X8; go X9; go X10
| _idtac
end.

For faster performance, one may deactivate rm_inside by replacing the body of this definition with idtac.

Ltac fast_rm_inside E :=
rm_inside E.

(* ---------------------------------------------------------------------- *)

## Numbers as arguments

When tactic takes a natural number as argument, it may be parsed either as a natural number or as a relative number. In order for tactics to convert their arguments into natural numbers, we provide a conversion tactic.

(* COQ-8.4:
Require Coq.Numbers.BinNums Coq.ZArith.BinInt. *)

Require BinPos Coq.ZArith.BinInt.

Definition ltac_nat_from_int (x:BinInt.Z) : nat :=
match x with
| BinInt.Z0 ⇒ 0%nat
| BinInt.Zpos pBinPos.nat_of_P p
| BinInt.Zneg p ⇒ 0%nat
end.

Ltac nat_from_number N :=
match type of N with
| natconstr:(N)
| BinInt.Zlet N' := constr:(ltac_nat_from_int N) in eval compute in N'
end.

ltac_pattern E at K is the same as pattern E at K except that K is a Coq natural rather than a Ltac integer. Syntax ltac_pattern E as K in H is also available.

Tactic Notation "ltac_pattern" constr(E) "at" constr(K) :=
match nat_from_number K with
| 1 ⇒ pattern E at 1
| 2 ⇒ pattern E at 2
| 3 ⇒ pattern E at 3
| 4 ⇒ pattern E at 4
| 5 ⇒ pattern E at 5
| 6 ⇒ pattern E at 6
| 7 ⇒ pattern E at 7
| 8 ⇒ pattern E at 8
end.

Tactic Notation "ltac_pattern" constr(E) "at" constr(K) "in" hyp(H) :=
match nat_from_number K with
| 1 ⇒ pattern E at 1 in H
| 2 ⇒ pattern E at 2 in H
| 3 ⇒ pattern E at 3 in H
| 4 ⇒ pattern E at 4 in H
| 5 ⇒ pattern E at 5 in H
| 6 ⇒ pattern E at 6 in H
| 7 ⇒ pattern E at 7 in H
| 8 ⇒ pattern E at 8 in H
end.

(* ---------------------------------------------------------------------- *)

## Testing tactics

show tac executes a tactic tac that produces a result, and then display its result.

Tactic Notation "show" tactic(tac) :=
let R := tac in pose R.

dup N produces N copies of the current goal. It is useful for building examples on which to illustrate behaviour of tactics. dup is short for dup 2.

Lemma dup_lemma : P, P P P.
Proof using. auto. Qed.

Ltac dup_tactic N :=
match nat_from_number N with
| 0 ⇒ idtac
| S 0 ⇒ idtac
| S ?N'apply dup_lemma; [ | dup_tactic N' ]
end.

Tactic Notation "dup" constr(N) :=
dup_tactic N.
Tactic Notation "dup" :=
dup 2.

(* ---------------------------------------------------------------------- *)

## Check no evar in goal

(* COQ8.4:
Ltac check_noevar M :=
match M with M => idtac end.

Ltac check_noevar_hyp H := (* todo: imlement using check_noevar *)
let T := type of H in
match type of H with T => idtac end.

Ltac check_noevar_goal := (* todo: imlement using check_noevar *)
match goal with |- ?G => match G with G => idtac end end.
*)

Ltac check_noevar M :=
first [ has_evar M; fail 2 | idtac ].

Ltac check_noevar_hyp H := (* todo: imlement using check_noevar *)
let T := type of H in check_noevar T.
Ltac check_noevar_goal := (* todo: imlement using check_noevar *)
match goal with ?Gcheck_noevar G end.

(* ---------------------------------------------------------------------- *)

## Helper function for introducing evars

with_evar T (fun M tac) creates a new evar that can be used in the tactic tac under the name M.

Ltac with_evar_base T cont :=
let x := fresh in evar (x:T); cont x; subst x.

Tactic Notation "with_evar" constr(T) tactic(cont) :=
with_evar_base T cont.

(* ---------------------------------------------------------------------- *)

## Tagging of hypotheses

get_last_hyp tt is a function that returns the last hypothesis at the bottom of the context. It is useful to obtain the default name associated with the hypothesis, e.g. intro; let H := get_last_hyp tt in let H' := fresh "P" H in ...

Ltac get_last_hyp tt :=
match goal with H: _ _constr:(H) end.

(* ---------------------------------------------------------------------- *)

## Tagging of hypotheses

ltac_tag_subst is a specific marker for hypotheses which is used to tag hypotheses that are equalities to be substituted.

Definition ltac_tag_subst (A:Type) (x:A) := x.

ltac_to_generalize is a specific marker for hypotheses to be generalized.

Definition ltac_to_generalize (A:Type) (x:A) := x.

Ltac gen_to_generalize :=
repeat match goal with
H: ltac_to_generalize _ _generalize H; clear H end.

Ltac mark_to_generalize H :=
let T := type of H in
change T with (ltac_to_generalize T) in H.

(* ---------------------------------------------------------------------- *)

## Deconstructing terms

get_head E is a tactic that returns the head constant of the term E, ie, when applied to a term of the form P x1 ... xN it returns P. If E is not an application, it returns E. Warning: the tactic seems to loop in some cases when the goal is a product and one uses the result of this function.

Ltac get_head E :=
match E with
| ?P _ _ _ _ _ _ _ _ _ _ _ _constr:(P)
| ?P _ _ _ _ _ _ _ _ _ _ _constr:(P)
| ?P _ _ _ _ _ _ _ _ _ _constr:(P)
| ?P _ _ _ _ _ _ _ _ _constr:(P)
| ?P _ _ _ _ _ _ _ _constr:(P)
| ?P _ _ _ _ _ _ _constr:(P)
| ?P _ _ _ _ _ _constr:(P)
| ?P _ _ _ _ _constr:(P)
| ?P _ _ _ _constr:(P)
| ?P _ _ _constr:(P)
| ?P _ _constr:(P)
| ?P _constr:(P)
| ?Pconstr:(P)
end.

get_fun_arg E is a tactic that decomposes an application term E, ie, when applied to a term of the form X1 ... XN it returns a pair made of X1 .. X(N-1) and XN.

Ltac get_fun_arg E :=
match E with
| ?X1 ?X2 ?X3 ?X4 ?X5 ?X6 ?X7 ?Xconstr:((X1 X2 X3 X4 X5 X6,X))
| ?X1 ?X2 ?X3 ?X4 ?X5 ?X6 ?Xconstr:((X1 X2 X3 X4 X5,X))
| ?X1 ?X2 ?X3 ?X4 ?X5 ?Xconstr:((X1 X2 X3 X4,X))
| ?X1 ?X2 ?X3 ?X4 ?Xconstr:((X1 X2 X3,X))
| ?X1 ?X2 ?X3 ?Xconstr:((X1 X2,X))
| ?X1 ?X2 ?Xconstr:((X1,X))
| ?X1 ?Xconstr:((X1,X))
end.

(* ---------------------------------------------------------------------- *)

## Action at occurence and action not at occurence

ltac_action_at K of E do Tac isolates the K-th occurence of E in the goal, setting it in the form P E for some named pattern P, then calls tactic Tac, and finally unfolds P. Syntax ltac_action_at K of E in H do Tac is also available.

Tactic Notation "ltac_action_at" constr(K) "of" constr(E) "do" tactic(Tac) :=
let p := fresh in ltac_pattern E at K;
match goal with ?P _set (p:=P) end;
Tac; unfold p; clear p.

Tactic Notation "ltac_action_at" constr(K) "of" constr(E) "in" hyp(H) "do" tactic(Tac) :=
let p := fresh in ltac_pattern E at K in H;
match type of H with ?P _set (p:=P) in H end;
Tac; unfold p in H; clear p.

protects E do Tac temporarily assigns a name to the expression E so that the execution of tactic Tac will not modify E. This is useful for instance to restrict the action of simpl.

Tactic Notation "protects" constr(E) "do" tactic(Tac) :=
(* let x := fresh "TEMP" in sets_eq x: E; T; subst x. *)
let x := fresh "TEMP" in let H := fresh "TEMP" in
set (X := E) in *; assert (H : X = E) by reflexivity;
clearbody X; Tac; subst x.

Tactic Notation "protects" constr(E) "do" tactic(Tac) "/" :=
protects E do Tac.

(* ---------------------------------------------------------------------- *)

## An alias for eq

eq' is an alias for eq to be used for equalities in inductive definitions, so that they don't get mixed with equalities generated by inversion.

Definition eq' := @eq.

Hint Unfold eq'.

Notation "x '='' y" := (@eq' _ x y)
(at level 70, y at next level).

(* ********************************************************************** *)

# Common tactics for simplifying goals like intuition

Ltac jauto_set_hyps :=
repeat match goal with H: ?T _
match T with
| _ _destruct H
| a, _destruct H
| _generalize H; clear H
end
end.

Ltac jauto_set_goal :=
repeat match goal with
| a, _esplit
| _ _split
end.

Ltac jauto_set :=
intros; jauto_set_hyps;
intros; jauto_set_goal;
unfold not in *.

(* ********************************************************************** *)

# Backward and forward chaining

(* ---------------------------------------------------------------------- *)

## Application

Ltac old_refine f :=
refine f. (* ; shelve_unifiable. *)

rapply is a tactic similar to eapply except that it is based on the refine tactics, and thus is strictly more powerful (at least in theory :). In short, it is able to perform on-the-fly conversions when required for arguments to match, and it is able to instantiate existentials when required.

Tactic Notation "rapply" constr(t) :=
first (* todo: les @ sont inutiles *)
[ eexact (@t)
| refine (@t)
| refine (@t _)
| refine (@t _ _)
| refine (@t _ _ _)
| refine (@t _ _ _ _)
| refine (@t _ _ _ _ _)
| refine (@t _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _ _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _ _ _ _ _ _ _ _)
| refine (@t _ _ _ _ _ _ _ _ _ _ _ _ _ _ _)
].

The tactics applys_N T, where N is a natural number, provides a more efficient way of using applys T. It avoids trying out all possible arities, by specifying explicitely the arity of function T.

Tactic Notation "rapply_0" constr(t) :=
refine (@t).
Tactic Notation "rapply_1" constr(t) :=
refine (@t _).
Tactic Notation "rapply_2" constr(t) :=
refine (@t _ _).
Tactic Notation "rapply_3" constr(t) :=
refine (@t _ _ _).
Tactic Notation "rapply_4" constr(t) :=
refine (@t _ _ _ _).
Tactic Notation "rapply_5" constr(t) :=
refine (@t _ _ _ _ _).
Tactic Notation "rapply_6" constr(t) :=
refine (@t _ _ _ _ _ _).
Tactic Notation "rapply_7" constr(t) :=
refine (@t _ _ _ _ _ _ _).
Tactic Notation "rapply_8" constr(t) :=
refine (@t _ _ _ _ _ _ _ _).
Tactic Notation "rapply_9" constr(t) :=
refine (@t _ _ _ _ _ _ _ _ _).
Tactic Notation "rapply_10" constr(t) :=
refine (@t _ _ _ _ _ _ _ _ _ _).

lets_base H E adds an hypothesis H : T to the context, where T is the type of term E. If H is an introduction pattern, it will destruct H according to the pattern.

Ltac lets_base I E := generalize E; intros I.

applys_to H E transform the type of hypothesis H by replacing it by the result of the application of the term E to H. Intuitively, it is equivalent to lets H: (E H).

Tactic Notation "applys_to" hyp(H) constr(E) :=
let H' := fresh in rename H into H';
(first [ lets_base H (E H')
| lets_base H (E _ H')
| lets_base H (E _ _ H')
| lets_base H (E _ _ _ H')
| lets_base H (E _ _ _ _ H')
| lets_base H (E _ _ _ _ _ H')
| lets_base H (E _ _ _ _ _ _ H')
| lets_base H (E _ _ _ _ _ _ _ H')
| lets_base H (E _ _ _ _ _ _ _ _ H')
| lets_base H (E _ _ _ _ _ _ _ _ _ H') ]
); clear H'.

applys_to H1,...,HN E applys E to several hypotheses

Tactic Notation "applys_to" hyp(H1) "," hyp(H2) constr(E) :=
applys_to H1 E; applys_to H2 E.
Tactic Notation "applys_to" hyp(H1) "," hyp(H2) "," hyp(H3) constr(E) :=
applys_to H1 E; applys_to H2 E; applys_to H3 E.
Tactic Notation "applys_to" hyp(H1) "," hyp(H2) "," hyp(H3) "," hyp(H4) constr(E) :=
applys_to H1 E; applys_to H2 E; applys_to H3 E; applys_to H4 E.

constructors calls constructor or econstructor.

Tactic Notation "constructors" :=
first [ constructor | econstructor ]; unfold eq'.

(* ---------------------------------------------------------------------- *)

## Assertions

asserts H: T is another syntax for assert (H : T), which also works with introduction patterns. For instance, one can write: asserts \[x P\] ( n, n = 3), or asserts \[H|H\] (n = 0 n = 1).

Tactic Notation "asserts" simple_intropattern(I) ":" constr(T) :=
let H := fresh in assert (H : T);
[ | generalize H; clear H; intros I ].

asserts H1 .. HN: T is a shorthand for asserts \[H1 \[H2 \[.. HN\]\]\]\: T].

Tactic Notation "asserts" simple_intropattern(I1)
simple_intropattern(I2) ":" constr(T) :=
asserts [I1 I2]: T.
Tactic Notation "asserts" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) ":" constr(T) :=
asserts [I1 [I2 I3]]: T.
Tactic Notation "asserts" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) ":" constr(T) :=
asserts [I1 [I2 [I3 I4]]]: T.
Tactic Notation "asserts" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) simple_intropattern(I5) ":" constr(T) :=
asserts [I1 [I2 [I3 [I4 I5]]]]: T.
Tactic Notation "asserts" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) simple_intropattern(I5)
simple_intropattern(I6) ":" constr(T) :=
asserts [I1 [I2 [I3 [I4 [I5 I6]]]]]: T.

asserts: T is asserts H: T with H being chosen automatically.

Tactic Notation "asserts" ":" constr(T) :=
let H := fresh in asserts H : T.

cuts H: T is the same as asserts H: T except that the two subgoals generated are swapped: the subgoal T comes second. Note that contrary to cut, it introduces the hypothesis.

Tactic Notation "cuts" simple_intropattern(I) ":" constr(T) :=
cut (T); [ intros I | idtac ].

cuts: T is cuts H: T with H being chosen automatically.

Tactic Notation "cuts" ":" constr(T) :=
let H := fresh in cuts H: T.

cuts H1 .. HN: T is a shorthand for cuts \[H1 \[H2 \[.. HN\]\]\]\: T].

Tactic Notation "cuts" simple_intropattern(I1)
simple_intropattern(I2) ":" constr(T) :=
cuts [I1 I2]: T.
Tactic Notation "cuts" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) ":" constr(T) :=
cuts [I1 [I2 I3]]: T.
Tactic Notation "cuts" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) ":" constr(T) :=
cuts [I1 [I2 [I3 I4]]]: T.
Tactic Notation "cuts" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) simple_intropattern(I5) ":" constr(T) :=
cuts [I1 [I2 [I3 [I4 I5]]]]: T.
Tactic Notation "cuts" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) simple_intropattern(I5)
simple_intropattern(I6) ":" constr(T) :=
cuts [I1 [I2 [I3 [I4 [I5 I6]]]]]: T.

(* ---------------------------------------------------------------------- *)

## Instantiation and forward-chaining

The instantiation tactics are used to instantiate a lemma E (whose type is a product) on some arguments. The type of E is made of implications and universal quantifications, e.g. x, P x y z, Q x y z R z.
The first possibility is to provide arguments in order: first x, then a proof of P x, then y etc... In this mode, called "Args", all the arguments are to be provided. If a wildcard is provided (written __), then an existential variable will be introduced in place of the argument.
It is very convenient to give some arguments the lemma should be instantiated on, and let the tactic find out automatically where underscores should be insterted. Underscore arguments __ are interpret as follows: an underscore means that we want to skip the argument that has the same type as the next real argument provided (real means not an underscore). If there is no real argument after underscore, then the underscore is used for the first possible argument.
The general syntax is tactic (>> E1 .. EN) where tactic is the name of the tactic (possibly with some arguments) and Ei are the arguments. Moreover, some tactics accept the syntax tactic E1 .. EN as short for tactic (>> E1 .. EN) for values of N up to 5.
Finally, if the argument EN given is a triple-underscore ___, then it is equivalent to providing a list of wildcards, with the appropriate number of wildcards. This means that all the remaining arguments of the lemma will be instantiated. Definitions in the conclusion are not unfolded in this case.

(* Underlying implementation *)

Ltac app_assert t P cont :=
let H := fresh "TEMP" in
assert (H : P); [ | cont(t H); clear H ].

Ltac app_evar t A cont :=
let x := fresh "TEMP" in
evar (x:A);
let t' := constr:(t x) in
let t'' := (eval unfold x in t') in
subst x; cont t''.

Ltac app_arg t P v cont :=
let H := fresh "TEMP" in
assert (H : P); [ apply v | cont(t H); try clear H ].

Ltac build_app_alls t final :=
let rec go t :=
match type of t with
| ?P ?Qapp_assert t P go
| _:?A, _app_evar t A go
| _final t
end in
go t.

Ltac boxerlist_next_type vs :=
match vs with
| nilconstr:(ltac_wild)
| (boxer ltac_wild)::?vs'boxerlist_next_type vs'
| (boxer ltac_wilds)::_ ⇒ constr:(ltac_wild)
| (@boxer ?T _)::_ ⇒ constr:(T)
end.

(* Note: refuse to instantiate a dependent hypothesis with a proposition;
refuse to instantiate an argument of type Type with one that
does not have the type Type.
*)

Ltac build_app_hnts t vs final :=
let rec go t vs :=
match vs with
| nilfirst [ final t | fail 1 ]
| (boxer ltac_wilds)::_ ⇒ first [ build_app_alls t final | fail 1 ]
| (boxer ?v)::?vs'
let cont t' := go t' vs in
let cont' t' := go t' vs' in
let T := type of t in
let T := eval hnf in T in
match v with
| ltac_wild
first [ let U := boxerlist_next_type vs' in
match U with
| ltac_wild
match T with
| ?P ?Qfirst [ app_assert t P cont' | fail 3 ]
| _:?A, _first [ app_evar t A cont' | fail 3 ]
end
| _
match T with (* should test T for unifiability *)
| U ?Qfirst [ app_assert t U cont' | fail 3 ]
| _:U, _first [ app_evar t U cont' | fail 3 ]
| ?P ?Qfirst [ app_assert t P cont | fail 3 ]
| _:?A, _first [ app_evar t A cont | fail 3 ]
end
end
| fail 2 ]
| _
match T with
| ?P ?Qfirst [ app_arg t P v cont'
| app_assert t P cont
| fail 3 ]
| _:Type, _
match type of v with
| Typefirst [ cont' (t v)
| app_evar t Type cont
| fail 3 ]
| _first [ app_evar t Type cont
| fail 3 ]
end
| _:?A, _
let V := type of v in
match type of V with
| Propfirst [ app_evar t A cont
| fail 3 ]
| _first [ cont' (t v)
| app_evar t A cont
| fail 3 ]
end
end
end
end in
go t vs.

newer version : support for typeclasses

Ltac app_typeclass t cont :=
let t' := constr:(t _) in
cont t'.

Ltac build_app_alls t final ::=
let rec go t :=
match type of t with
| ?P ?Qapp_assert t P go
| _:?A, _
first [ app_evar t A go
| app_typeclass t go
| fail 3 ]
| _final t
end in
go t.

Ltac build_app_hnts t vs final ::=
let rec go t vs :=
match vs with
| nilfirst [ final t | fail 1 ]
| (boxer ltac_wilds)::_ ⇒ first [ build_app_alls t final | fail 1 ]
| (boxer ?v)::?vs'
let cont t' := go t' vs in
let cont' t' := go t' vs' in
let T := type of t in
let T := eval hnf in T in
match v with
| ltac_wild
first [ let U := boxerlist_next_type vs' in
match U with
| ltac_wild
match T with
| ?P ?Qfirst [ app_assert t P cont' | fail 3 ]
| _:?A, _first [ app_typeclass t cont'
| app_evar t A cont'
| fail 3 ]
end
| _
match T with (* should test T for unifiability *)
| U ?Qfirst [ app_assert t U cont' | fail 3 ]
| _:U, _first
[ app_typeclass t cont'
| app_evar t U cont'
| fail 3 ]
| ?P ?Qfirst [ app_assert t P cont | fail 3 ]
| _:?A, _first
[ app_typeclass t cont
| app_evar t A cont
| fail 3 ]
end
end
| fail 2 ]
| _
match T with
| ?P ?Qfirst [ app_arg t P v cont'
| app_assert t P cont
| fail 3 ]
| _:Type, _
match type of v with
| Typefirst [ cont' (t v)
| app_evar t Type cont
| fail 3 ]
| _first [ app_evar t Type cont
| fail 3 ]
end
| _:?A, _
let V := type of v in
match type of V with
| Propfirst [ app_typeclass t cont
| app_evar t A cont
| fail 3 ]
| _first [ cont' (t v)
| app_typeclass t cont
| app_evar t A cont
| fail 3 ]
end
end
end
end in
go t vs.
(* todo: use local function for first ... *)

(*--old version
Ltac build_app_hnts t vs final :=
let rec go t vs :=
match vs with
| nil => first  final t | fail 1
| (boxer ltac_wilds)::_ => first  build_app_alls t final | fail 1
| (boxer ?v)::?vs' =>
let cont t' := go t' vs in
let cont' t' := go t' vs' in
let T := type of t in
let T := eval hnf in T in
match v with
| ltac_wild =>
first  let U := boxerlist_next_type vs' in match U with | ltac_wild match T with | ?P ?Q first [ app_assert t P cont' | fail 3 ] | _:?A, _ first [ app_evar t A cont' | fail 3 ] end | _ match T with  should test T for unifiability *)
| U ?Q first [ app_assert t U cont' | fail 3 ] | _:U, _ first [ app_evar t U cont' | fail 3 ] | ?P ?Q first [ app_assert t P cont | fail 3 ] | _:?A, _ first [ app_evar t A cont | fail 3 ] end end | fail 2
| _ =>
match T with
| ?P -> ?Q => first  app_arg t P v cont' | app_assert t P cont | fail 3
| forall _:?A, _ => first  cont' (t v) | app_evar t A cont | fail 3
end
end
end in
go t vs.
*)

Ltac build_app args final :=
first [
match args with (@boxer ?T ?t)::?vs
let t := constr:(t:T) in
build_app_hnts t vs final;
fast_rm_inside args
end
| fail 1 "Instantiation fails for:" args].

Ltac unfold_head_until_product T :=
eval hnf in T.

Ltac args_unfold_head_if_not_product args :=
match args with (@boxer ?T ?t)::?vs
let T' := unfold_head_until_product T in
constr:((@boxer T' t)::vs)
end.

Ltac args_unfold_head_if_not_product_but_params args :=
match args with
| (boxer ?t)::(boxer ?v)::?vs
| _constr:(args)
end.

lets H: (>> E0 E1 .. EN) will instantiate lemma E0 on the arguments Ei (which may be wildcards __), and name H the resulting term. H may be an introduction pattern, or a sequence of introduction patterns I1 I2 IN, or empty. Syntax lets H: E0 E1 .. EN is also available. If the last argument EN is ___ (triple-underscore), then all arguments of H will be instantiated.

Ltac lets_build I Ei :=
let args := list_boxer_of Ei in
let args := args_unfold_head_if_not_product_but_params args in
(*    let Ei''' := args_unfold_head_if_not_product Ei'' in*)
build_app args ltac:(fun Rlets_base I R).

Tactic Notation "lets" simple_intropattern(I) ":" constr(E) :=
lets_build I E.
Tactic Notation "lets" ":" constr(E) :=
let H := fresh in lets H: E.
Tactic Notation "lets" ":" constr(E0)
constr(A1) :=
lets: (>> E0 A1).
Tactic Notation "lets" ":" constr(E0)
constr(A1) constr(A2) :=
lets: (>> E0 A1 A2).
Tactic Notation "lets" ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
lets: (>> E0 A1 A2 A3).
Tactic Notation "lets" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
lets: (>> E0 A1 A2 A3 A4).
Tactic Notation "lets" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
lets: (>> E0 A1 A2 A3 A4 A5).

(* --todo: deprecated, do not use *)
Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2)
":" constr(E) :=
lets [I1 I2]: E.
Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) ":" constr(E) :=
lets [I1 [I2 I3]]: E.
Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) ":" constr(E) :=
lets [I1 [I2 [I3 I4]]]: E.
Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) simple_intropattern(I5)
":" constr(E) :=
lets [I1 [I2 [I3 [I4 I5]]]]: E.

Tactic Notation "lets" simple_intropattern(I) ":" constr(E0)
constr(A1) :=
lets I: (>> E0 A1).
Tactic Notation "lets" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) :=
lets I: (>> E0 A1 A2).
Tactic Notation "lets" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
lets I: (>> E0 A1 A2 A3).
Tactic Notation "lets" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
lets I: (>> E0 A1 A2 A3 A4).
Tactic Notation "lets" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
lets I: (>> E0 A1 A2 A3 A4 A5).

Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2) ":" constr(E0)
constr(A1) :=
lets [I1 I2]: E0 A1.
Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2) ":" constr(E0)
constr(A1) constr(A2) :=
lets [I1 I2]: E0 A1 A2.
Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2) ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
lets [I1 I2]: E0 A1 A2 A3.
Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
lets [I1 I2]: E0 A1 A2 A3 A4.
Tactic Notation "lets" simple_intropattern(I1) simple_intropattern(I2) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
lets [I1 I2]: E0 A1 A2 A3 A4 A5.

forwards H: (>> E0 E1 .. EN) is short for forwards H: (>> E0 E1 .. EN ___). The arguments Ei can be wildcards __ (except E0). H may be an introduction pattern, or a sequence of introduction pattern, or empty. Syntax forwards H: E0 E1 .. EN is also available.

Ltac forwards_build_app_arg Ei :=
let args := list_boxer_of Ei in
let args := (eval simpl in (args ++ ((boxer ___)::nil))) in
let args := args_unfold_head_if_not_product args in
args.

Ltac forwards_then Ei cont :=
let args := forwards_build_app_arg Ei in
let args := args_unfold_head_if_not_product_but_params args in
build_app args cont.

Tactic Notation "forwards" simple_intropattern(I) ":" constr(Ei) :=
let args := forwards_build_app_arg Ei in
lets I: args.

Tactic Notation "forwards" ":" constr(E) :=
let H := fresh in forwards H: E.
Tactic Notation "forwards" ":" constr(E0)
constr(A1) :=
forwards: (>> E0 A1).
Tactic Notation "forwards" ":" constr(E0)
constr(A1) constr(A2) :=
forwards: (>> E0 A1 A2).
Tactic Notation "forwards" ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
forwards: (>> E0 A1 A2 A3).
Tactic Notation "forwards" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
forwards: (>> E0 A1 A2 A3 A4).
Tactic Notation "forwards" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
forwards: (>> E0 A1 A2 A3 A4 A5).

(* todo: deprecated, do not use *)
Tactic Notation "forwards" simple_intropattern(I1) simple_intropattern(I2)
":" constr(E) :=
forwards [I1 I2]: E.
Tactic Notation "forwards" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) ":" constr(E) :=
forwards [I1 [I2 I3]]: E.
Tactic Notation "forwards" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) ":" constr(E) :=
forwards [I1 [I2 [I3 I4]]]: E.
Tactic Notation "forwards" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) simple_intropattern(I5)
":" constr(E) :=
forwards [I1 [I2 [I3 [I4 I5]]]]: E.

Tactic Notation "forwards" simple_intropattern(I) ":" constr(E0)
constr(A1) :=
forwards I: (>> E0 A1).
Tactic Notation "forwards" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) :=
forwards I: (>> E0 A1 A2).
Tactic Notation "forwards" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
forwards I: (>> E0 A1 A2 A3).
Tactic Notation "forwards" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
forwards I: (>> E0 A1 A2 A3 A4).
Tactic Notation "forwards" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
forwards I: (>> E0 A1 A2 A3 A4 A5).

(* for use by tactics -- todo: factorize better *)
Tactic Notation "forwards_nounfold" simple_intropattern(I) ":" constr(Ei) :=
let args := list_boxer_of Ei in
let args := (eval simpl in (args ++ ((boxer ___)::nil))) in
build_app args ltac:(fun Rlets_base I R).

Ltac forwards_nounfold_then Ei cont :=
let args := list_boxer_of Ei in
let args := (eval simpl in (args ++ ((boxer ___)::nil))) in
build_app args cont.

applys (>> E0 E1 .. EN) instantiates lemma E0 on the arguments Ei (which may be wildcards __), and apply the resulting term to the current goal, using the tactic applys defined earlier on. applys E0 E1 E2 .. EN is also available.

Ltac applys_build Ei :=
let args := list_boxer_of Ei in
let args := args_unfold_head_if_not_product_but_params args in
build_app args ltac:(fun R
first [ apply R | eapply R | rapply R ]).

Ltac applys_base E :=
match type of E with
| list Boxerapplys_build E
| _first [ rapply E | applys_build E ]
end; fast_rm_inside E.

Tactic Notation "applys" constr(E) :=
applys_base E.
Tactic Notation "applys" constr(E0) constr(A1) :=
applys (>> E0 A1).
Tactic Notation "applys" constr(E0) constr(A1) constr(A2) :=
applys (>> E0 A1 A2).
Tactic Notation "applys" constr(E0) constr(A1) constr(A2) constr(A3) :=
applys (>> E0 A1 A2 A3).
Tactic Notation "applys" constr(E0) constr(A1) constr(A2) constr(A3) constr(A4) :=
applys (>> E0 A1 A2 A3 A4).
Tactic Notation "applys" constr(E0) constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
applys (>> E0 A1 A2 A3 A4 A5).

fapplys (>> E0 E1 .. EN) instantiates lemma E0 on the arguments Ei and on the argument ___ meaning that all evars should be explicitly instantiated, and apply the resulting term to the current goal. fapplys E0 E1 E2 .. EN is also available.

Ltac fapplys_build Ei :=
let args := list_boxer_of Ei in
let args := (eval simpl in (args ++ ((boxer ___)::nil))) in
let args := args_unfold_head_if_not_product_but_params args in
build_app args ltac:(fun Rapply R).

Tactic Notation "fapplys" constr(E0) := (* todo: use the tactic for that*)
match type of E0 with
| list Boxerfapplys_build E0
| _fapplys_build (>> E0)
end.
Tactic Notation "fapplys" constr(E0) constr(A1) :=
fapplys (>> E0 A1).
Tactic Notation "fapplys" constr(E0) constr(A1) constr(A2) :=
fapplys (>> E0 A1 A2).
Tactic Notation "fapplys" constr(E0) constr(A1) constr(A2) constr(A3) :=
fapplys (>> E0 A1 A2 A3).
Tactic Notation "fapplys" constr(E0) constr(A1) constr(A2) constr(A3) constr(A4) :=
fapplys (>> E0 A1 A2 A3 A4).
Tactic Notation "fapplys" constr(E0) constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
fapplys (>> E0 A1 A2 A3 A4 A5).

specializes H (>> E1 E2 .. EN) will instantiate hypothesis H on the arguments Ei (which may be wildcards __). If the last argument EN is ___ (triple-underscore), then all arguments of H get instantiated.

Ltac specializes_build H Ei :=
let H' := fresh "TEMP" in rename H into H';
let args := list_boxer_of Ei in
let args := constr:((boxer H')::args) in
let args := args_unfold_head_if_not_product args in
build_app args ltac:(fun Rlets H: R);
clear H'.

Ltac specializes_base H Ei :=
specializes_build H Ei; fast_rm_inside Ei.

Tactic Notation "specializes" hyp(H) :=
specializes_base H (___).
Tactic Notation "specializes" hyp(H) constr(A) :=
specializes_base H A.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) :=
specializes H (>> A1 A2).
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) :=
specializes H (>> A1 A2 A3).
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) constr(A4) :=
specializes H (>> A1 A2 A3 A4).
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
specializes H (>> A1 A2 A3 A4 A5).

specializes_vars H is equivalent to specializes H __ .. __ with as many double underscore as the number of dependent arguments visible from the type of H. Note that no unfolding is currently being performed (this behavior might change in the future). The current implementation is restricted to the case where H is an existing hypothesis — TODO: generalize.

Ltac specializes_var_base H :=
match type of H with
| ?P ?Qfail 1
| _:_, _specializes H __
end.

Ltac specializes_vars_base H :=
repeat (specializes_var_base H).

Tactic Notation "specializes_var" hyp(H) :=
specializes_var_base H.

Tactic Notation "specializes_vars" hyp(H) :=
specializes_vars_base H.

(* ---------------------------------------------------------------------- *)

## Experimental tactics for application

fapply is a version of apply based on forwards.

Tactic Notation "fapply" constr(E) :=
let H := fresh in forwards H: E;
first [ apply H | eapply H | rapply H | hnf; apply H
| hnf; eapply H | applys H ].
(* todo: is applys redundant with rapply ? *)

sapply stands for "super apply". It tries apply, eapply, applys and fapply, and also tries to head-normalize the goal first.

Tactic Notation "sapply" constr(H) :=
first [ apply H | eapply H | rapply H | applys H
| hnf; apply H | hnf; eapply H | hnf; applys H
| fapply H ].

(* ---------------------------------------------------------------------- *)

lets_simpl H: E is the same as lets H: E excepts that it calls simpl on the hypothesis H. lets_simpl: E is also provided.

Tactic Notation "lets_simpl" ident(H) ":" constr(E) :=
lets H: E; try simpl in H.

Tactic Notation "lets_simpl" ":" constr(T) :=
let H := fresh in lets_simpl H: T.

lets_hnf H: E is the same as lets H: E excepts that it calls hnf to set the definition in head normal form. lets_hnf: E is also provided.

Tactic Notation "lets_hnf" ident(H) ":" constr(E) :=
lets H: E; hnf in H.

Tactic Notation "lets_hnf" ":" constr(T) :=
let H := fresh in lets_hnf H: T.

puts X: E is a synonymous for pose (X := E). Alternative syntax is puts: E.

Tactic Notation "puts" ident(X) ":" constr(E) :=
pose (X := E).
Tactic Notation "puts" ":" constr(E) :=
let X := fresh "X" in pose (X := E).

(* ---------------------------------------------------------------------- *)

## Application of tautologies

logic E, where E is a fact, is equivalent to assert H:E; [tauto | eapply H; clear H]. It is useful for instance to prove a conjunction [A B] by showing first [A] and then [A B], through the command [logic (foral A B, A (A B) A B)]

Ltac logic_base E cont :=
assert (H:E); [ cont tt | eapply H; clear H ].

Tactic Notation "logic" constr(E) :=
logic_base E ltac:(fun _tauto).

(* ---------------------------------------------------------------------- *)

## Application modulo equalities

The tactic equates replaces a goal of the form P x y z with a goal of the form P x ?a z and a subgoal ?a = y. The introduction of the evar ?a makes it possible to apply lemmas that would not apply to the original goal, for example a lemma of the form n m, P n n m, because x and y might be equal but not convertible.
Usage is equates i1 ... ik, where the indices are the positions of the arguments to be replaced by evars, counting from the right-hand side. If 0 is given as argument, then the entire goal is replaced by an evar.

Section equatesLemma.
Variables (A0 A1 : Type).
Variables (A2 : (x1 : A1), Type).
Variables (A3 : (x1 : A1) (x2 : A2 x1), Type).
Variables (A4 : (x1 : A1) (x2 : A2 x1) (x3 : A3 x2), Type).
Variables (A5 : (x1 : A1) (x2 : A2 x1) (x3 : A3 x2) (x4 : A4 x3), Type).
Variables (A6 : (x1 : A1) (x2 : A2 x1) (x3 : A3 x2) (x4 : A4 x3) (x5 : A5 x4), Type).

Lemma equates_0 : (P Q:Prop),
P P = Q Q.
Proof. intros. subst. auto. Qed.

Lemma equates_1 :
(P:A0Prop) x1 y1,
P y1 x1 = y1 P x1.
Proof. intros. subst. auto. Qed.

Lemma equates_2 :
y1 (P:A0(x1:A1),Prop) x1 x2,
P y1 x2 x1 = y1 P x1 x2.
Proof. intros. subst. auto. Qed.

Lemma equates_3 :
y1 (P:A0(x1:A1)(x2:A2 x1),Prop) x1 x2 x3,
P y1 x2 x3 x1 = y1 P x1 x2 x3.
Proof. intros. subst. auto. Qed.

Lemma equates_4 :
y1 (P:A0(x1:A1)(x2:A2 x1)(x3:A3 x2),Prop) x1 x2 x3 x4,
P y1 x2 x3 x4 x1 = y1 P x1 x2 x3 x4.
Proof. intros. subst. auto. Qed.

Lemma equates_5 :
y1 (P:A0(x1:A1)(x2:A2 x1)(x3:A3 x2)(x4:A4 x3),Prop) x1 x2 x3 x4 x5,
P y1 x2 x3 x4 x5 x1 = y1 P x1 x2 x3 x4 x5.
Proof. intros. subst. auto. Qed.

Lemma equates_6 :
y1 (P:A0(x1:A1)(x2:A2 x1)(x3:A3 x2)(x4:A4 x3)(x5:A5 x4),Prop)
x1 x2 x3 x4 x5 x6,
P y1 x2 x3 x4 x5 x6 x1 = y1 P x1 x2 x3 x4 x5 x6.
Proof. intros. subst. auto. Qed.

End equatesLemma.

Ltac equates_lemma n :=
match nat_from_number n with
| 0 ⇒ constr:(equates_0)
| 1 ⇒ constr:(equates_1)
| 2 ⇒ constr:(equates_2)
| 3 ⇒ constr:(equates_3)
| 4 ⇒ constr:(equates_4)
| 5 ⇒ constr:(equates_5)
| 6 ⇒ constr:(equates_6)
end.

Ltac equates_one n :=
let L := equates_lemma n in
eapply L.

Ltac equates_several E cont :=
let all_pos := match type of E with
| List.list Boxerconstr:(E)
| _constr:((boxer E)::nil)
end in
let rec go pos :=
match pos with
| nilcont tt
| (boxer ?n)::?pos'equates_one n; [ instantiate; go pos' | ]
end in
go all_pos.

Tactic Notation "equates" constr(E) :=
equates_several E ltac:(fun _idtac).
Tactic Notation "equates" constr(n1) constr(n2) :=
equates (>> n1 n2).
Tactic Notation "equates" constr(n1) constr(n2) constr(n3) :=
equates (>> n1 n2 n3).
Tactic Notation "equates" constr(n1) constr(n2) constr(n3) constr(n4) :=
equates (>> n1 n2 n3 n4).

applys_eq H i1 .. iK is the same as equates i1 .. iK followed by apply H on the first subgoal.

Tactic Notation "applys_eq" constr(H) constr(E) :=
equates_several E ltac:(fun _sapply H).
Tactic Notation "applys_eq" constr(H) constr(n1) constr(n2) :=
applys_eq H (>> n1 n2).
Tactic Notation "applys_eq" constr(H) constr(n1) constr(n2) constr(n3) :=
applys_eq H (>> n1 n2 n3).
Tactic Notation "applys_eq" constr(H) constr(n1) constr(n2) constr(n3) constr(n4) :=
applys_eq H (>> n1 n2 n3 n4).

(* ---------------------------------------------------------------------- *)

## Absurd goals

false_goal replaces any goal by the goal False. Contrary to the tactic false (below), it does not try to do anything else

Tactic Notation "false_goal" :=
elimtype False.

false_post is the underlying tactic used to prove goals of the form False. In the default implementation, it proves the goal if the context contains False or an hypothesis of the form C x1 .. xN = D y1 .. yM, or if the congruence tactic finds a proof of x x for some x.

Ltac false_post :=
solve [ assumption | discriminate | congruence ].

false replaces any goal by the goal False, and calls false_post

Tactic Notation "false" :=
false_goal; try false_post.

tryfalse tries to solve a goal by contradiction, and leaves the goal unchanged if it cannot solve it. It is equivalent to try solve \[ false \].

Tactic Notation "tryfalse" :=
try solve [ false ].

false E tries to exploit lemma E to prove the goal false. false E1 .. EN is equivalent to false (>> E1 .. EN), which tries to apply applys (>> E1 .. EN) and if it does not work then tries forwards H: (>> E1 .. EN) followed with false

Ltac false_then E cont :=
false_goal; first
[ applys E; instantiate
| forwards_then E ltac:(fun M
pose M; jauto_set_hyps; intros; false) ];
cont tt.
(* TODO: is cont needed? *)

Tactic Notation "false" constr(E) :=
false_then E ltac:(fun _idtac).
Tactic Notation "false" constr(E) constr(E1) :=
false (>> E E1).
Tactic Notation "false" constr(E) constr(E1) constr(E2) :=
false (>> E E1 E2).
Tactic Notation "false" constr(E) constr(E1) constr(E2) constr(E3) :=
false (>> E E1 E2 E3).
Tactic Notation "false" constr(E) constr(E1) constr(E2) constr(E3) constr(E4) :=
false (>> E E1 E2 E3 E4).

false_invert H proves a goal if it absurd after calling inversion H and false

Ltac false_invert_for H :=
let M := fresh in pose (M := H); inversion H; false.

Tactic Notation "false_invert" constr(H) :=
try solve [ false_invert_for H | false ].

false_invert proves any goal provided there is at least one hypothesis H in the context (or as a universally quantified hypothesis visible at the head of the goal) that can be proved absurd by calling inversion H.

Ltac false_invert_iter :=
match goal with H:_ _
solve [ inversion H; false
| clear H; false_invert_iter
| fail 2 ] end.

Tactic Notation "false_invert" :=
intros; solve [ false_invert_iter | false ].

tryfalse_invert H and tryfalse_invert are like the above but leave the goal unchanged if they don't solve it.

Tactic Notation "tryfalse_invert" constr(H) :=
try (false_invert H).

Tactic Notation "tryfalse_invert" :=
try false_invert.

false_neq_self_hyp proves any goal if the context contains an hypothesis of the form E E. It is a restricted and optimized version of false. It is intended to be used by other tactics only.

Ltac false_neq_self_hyp :=
match goal with H: ?x ≠ ?x _
false_goal; apply H; reflexivity end.

(* ********************************************************************** *)

# Introduction and generalization

(* ---------------------------------------------------------------------- *)

## Introduction

introv is used to name only non-dependent hypothesis.
• If introv is called on a goal of the form x, H, it should introduce all the variables quantified with a at the head of the goal, but it does not introduce hypotheses that preceed an arrow constructor, like in P Q.
• If introv is called on a goal that is not of the form x, H nor P Q, the tactic unfolds definitions until the goal takes the form x, H or P Q. If unfolding definitions does not produces a goal of this form, then the tactic introv does nothing at all.

(* introv_rec introduces all visible variables.
It does not try to unfold any definition. *)

Ltac introv_rec :=
match goal with
| ?P ?Qidtac
| _, _intro; introv_rec
| _idtac
end.

(* introv_noarg forces the goal to be a  or an ,
and then calls introv_rec to introduces variables
(possibly none, in which case introv is the same as hnf).
If the goal is not a product, then it does not do anything. *)

Ltac introv_noarg :=
match goal with
| ?P ?Qidtac
| _, _introv_rec
| ?Ghnf;
match goal with
| ?P ?Qidtac
| _, _introv_rec
end
| _idtac
end.

(* simpler yet perhaps less efficient imlementation *)
Ltac introv_noarg_not_optimized :=
intro; match goal with H:_|-_ ⇒ revert H end; introv_rec.

(* introv_arg H introduces one non-dependent hypothesis
under the name H, after introducing the variables
quantified with a  that preceeds this hypothesis.
This tactic fails if there does not exist a hypothesis
to be introduced. *)

(* todo: __ in introv means "intros" *)

Ltac introv_arg H :=
hnf; match goal with
| ?P ?Qintros H
| _, _intro; introv_arg H
end.

(* introv I1 .. IN iterates introv Ik *)

Tactic Notation "introv" :=
introv_noarg.
Tactic Notation "introv" simple_intropattern(I1) :=
introv_arg I1.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2) :=
introv I1; introv I2.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) :=
introv I1; introv I2 I3.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) :=
introv I1; introv I2 I3 I4.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) simple_intropattern(I5) :=
introv I1; introv I2 I3 I4 I5.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) simple_intropattern(I5)
simple_intropattern(I6) :=
introv I1; introv I2 I3 I4 I5 I6.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) simple_intropattern(I5)
simple_intropattern(I6) simple_intropattern(I7) :=
introv I1; introv I2 I3 I4 I5 I6 I7.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) simple_intropattern(I5)
simple_intropattern(I6) simple_intropattern(I7) simple_intropattern(I8) :=
introv I1; introv I2 I3 I4 I5 I6 I7 I8.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) simple_intropattern(I5)
simple_intropattern(I6) simple_intropattern(I7) simple_intropattern(I8)
simple_intropattern(I9) :=
introv I1; introv I2 I3 I4 I5 I6 I7 I8 I9.
Tactic Notation "introv" simple_intropattern(I1) simple_intropattern(I2)
simple_intropattern(I3) simple_intropattern(I4) simple_intropattern(I5)
simple_intropattern(I6) simple_intropattern(I7) simple_intropattern(I8)
simple_intropattern(I9) simple_intropattern(I10) :=
introv I1; introv I2 I3 I4 I5 I6 I7 I8 I9 I10.

intros_all repeats intro as long as possible. Contrary to intros, it unfolds any definition on the way. Remark that it also unfolds the definition of negation, so applying introz to a goal of the form x, P x ¬Q will introduce x and P x and Q, and will leave False in the goal.

Tactic Notation "intros_all" :=
repeat intro.

intros_hnf introduces an hypothesis and sets in head normal form

Tactic Notation "intro_hnf" :=
intro; match goal with H: _ _hnf in H end.

(* ---------------------------------------------------------------------- *)

## Generalization

gen X1 .. XN is a shorthand for calling generalize dependent successively on variables XN...X1. Note that the variables are generalized in reverse order, following the convention of the generalize tactic: it means that X1 will be the first quantified variable in the resulting goal.

Tactic Notation "gen" ident(X1) :=
generalize dependent X1.
Tactic Notation "gen" ident(X1) ident(X2) :=
gen X2; gen X1.
Tactic Notation "gen" ident(X1) ident(X2) ident(X3) :=
gen X3; gen X2; gen X1.
Tactic Notation "gen" ident(X1) ident(X2) ident(X3) ident(X4) :=
gen X4; gen X3; gen X2; gen X1.
Tactic Notation "gen" ident(X1) ident(X2) ident(X3) ident(X4) ident(X5) :=
gen X5; gen X4; gen X3; gen X2; gen X1.
Tactic Notation "gen" ident(X1) ident(X2) ident(X3) ident(X4) ident(X5)
ident(X6) :=
gen X6; gen X5; gen X4; gen X3; gen X2; gen X1.
Tactic Notation "gen" ident(X1) ident(X2) ident(X3) ident(X4) ident(X5)
ident(X6) ident(X7) :=
gen X7; gen X6; gen X5; gen X4; gen X3; gen X2; gen X1.
Tactic Notation "gen" ident(X1) ident(X2) ident(X3) ident(X4) ident(X5)
ident(X6) ident(X7) ident(X8) :=
gen X8; gen X7; gen X6; gen X5; gen X4; gen X3; gen X2; gen X1.
Tactic Notation "gen" ident(X1) ident(X2) ident(X3) ident(X4) ident(X5)
ident(X6) ident(X7) ident(X8) ident(X9) :=
gen X9; gen X8; gen X7; gen X6; gen X5; gen X4; gen X3; gen X2; gen X1.
Tactic Notation "gen" ident(X1) ident(X2) ident(X3) ident(X4) ident(X5)
ident(X6) ident(X7) ident(X8) ident(X9) ident(X10) :=
gen X10; gen X9; gen X8; gen X7; gen X6; gen X5; gen X4; gen X3; gen X2; gen X1.

generalizes X is a shorthand for calling generalize X; clear X. It is weaker than tactic gen X since it does not support dependencies. It is mainly intended for writing tactics.

Tactic Notation "generalizes" hyp(X) :=
generalize X; clear X.
Tactic Notation "generalizes" hyp(X1) hyp(X2) :=
generalizes X1; generalizes X2.
Tactic Notation "generalizes" hyp(X1) hyp(X2) hyp(X3) :=
generalizes X1 X2; generalizes X3.
Tactic Notation "generalizes" hyp(X1) hyp(X2) hyp(X3) hyp(X4) :=
generalizes X1 X2 X3; generalizes X4.

(* ---------------------------------------------------------------------- *)

## Naming

sets X: E is the same as set (X := E) in *, that is, it replaces all occurences of E by a fresh meta-variable X whose definition is E.

Tactic Notation "sets" ident(X) ":" constr(E) :=
set (X := E) in *.

def_to_eq E X H applies when X := E is a local definition. It adds an assumption H: X = E and then clears the definition of X. def_to_eq_sym is similar except that it generates the equality H: E = X.

Ltac def_to_eq X HX E :=
assert (HX : X = E) by reflexivity; clearbody X.
Ltac def_to_eq_sym X HX E :=
assert (HX : E = X) by reflexivity; clearbody X.

set_eq X H: E generates the equality H: X = E, for a fresh name X, and replaces E by X in the current goal. Syntaxes set_eq X: E and set_eq: E are also available. Similarly, set_eq X H: E generates the equality H: E = X.
sets_eq X HX: E does the same but replaces E by X everywhere in the goal. sets_eq X HX: E in H replaces in H. set_eq X HX: E in performs no substitution at all.

Tactic Notation "set_eq" ident(X) ident(HX) ":" constr(E) :=
set (X := E); def_to_eq X HX E.
Tactic Notation "set_eq" ident(X) ":" constr(E) :=
let HX := fresh "EQ" X in set_eq X HX: E.
Tactic Notation "set_eq" ":" constr(E) :=
let X := fresh "X" in set_eq X: E.

Tactic Notation "set_eq" "" ident(X) ident(HX) ":" constr(E) :=
set (X := E); def_to_eq_sym X HX E.
Tactic Notation "set_eq" "" ident(X) ":" constr(E) :=
let HX := fresh "EQ" X in set_eq X HX: E.
Tactic Notation "set_eq" "" ":" constr(E) :=
let X := fresh "X" in set_eq X: E.

Tactic Notation "sets_eq" ident(X) ident(HX) ":" constr(E) :=
set (X := E) in *; def_to_eq X HX E.
Tactic Notation "sets_eq" ident(X) ":" constr(E) :=
let HX := fresh "EQ" X in sets_eq X HX: E.
Tactic Notation "sets_eq" ":" constr(E) :=
let X := fresh "X" in sets_eq X: E.

Tactic Notation "sets_eq" "" ident(X) ident(HX) ":" constr(E) :=
set (X := E) in *; def_to_eq_sym X HX E.
Tactic Notation "sets_eq" "" ident(X) ":" constr(E) :=
let HX := fresh "EQ" X in sets_eq X HX: E.
Tactic Notation "sets_eq" "" ":" constr(E) :=
let X := fresh "X" in sets_eq X: E.

Tactic Notation "set_eq" ident(X) ident(HX) ":" constr(E) "in" hyp(H) :=
set (X := E) in H; def_to_eq X HX E.
Tactic Notation "set_eq" ident(X) ":" constr(E) "in" hyp(H) :=
let HX := fresh "EQ" X in set_eq X HX: E in H.
Tactic Notation "set_eq" ":" constr(E) "in" hyp(H) :=
let X := fresh "X" in set_eq X: E in H.

Tactic Notation "set_eq" "" ident(X) ident(HX) ":" constr(E) "in" hyp(H) :=
set (X := E) in H; def_to_eq_sym X HX E.
Tactic Notation "set_eq" "" ident(X) ":" constr(E) "in" hyp(H) :=
let HX := fresh "EQ" X in set_eq X HX: E in H.
Tactic Notation "set_eq" "" ":" constr(E) "in" hyp(H) :=
let X := fresh "X" in set_eq X: E in H.

Tactic Notation "set_eq" ident(X) ident(HX) ":" constr(E) "in" "" :=
set (X := E) in ; def_to_eq X HX E.
Tactic Notation "set_eq" ident(X) ":" constr(E) "in" "" :=
let HX := fresh "EQ" X in set_eq X HX: E in .
Tactic Notation "set_eq" ":" constr(E) "in" "" :=
let X := fresh "X" in set_eq X: E in .

Tactic Notation "set_eq" "" ident(X) ident(HX) ":" constr(E) "in" "" :=
set (X := E) in ; def_to_eq_sym X HX E.
Tactic Notation "set_eq" "" ident(X) ":" constr(E) "in" "" :=
let HX := fresh "EQ" X in set_eq X HX: E in .
Tactic Notation "set_eq" "" ":" constr(E) "in" "" :=
let X := fresh "X" in set_eq X: E in .

gen_eq X: E is a tactic whose purpose is to introduce equalities so as to work around the limitation of the induction tactic which typically loses information. gen_eq E as X replaces all occurences of term E with a fresh variable X and the equality X = E as extra hypothesis to the current conclusion. In other words a conclusion C will be turned into (X = E) C. gen_eq: E and gen_eq: E as X are also accepted.

Tactic Notation "gen_eq" ident(X) ":" constr(E) :=
let EQ := fresh in sets_eq X EQ: E; revert EQ.
Tactic Notation "gen_eq" ":" constr(E) :=
let X := fresh "X" in gen_eq X: E.
Tactic Notation "gen_eq" ":" constr(E) "as" ident(X) :=
gen_eq X: E.
Tactic Notation "gen_eq" ident(X1) ":" constr(E1) ","
ident(X2) ":" constr(E2) :=
gen_eq X2: E2; gen_eq X1: E1.
Tactic Notation "gen_eq" ident(X1) ":" constr(E1) ","
ident(X2) ":" constr(E2) "," ident(X3) ":" constr(E3) :=
gen_eq X3: E3; gen_eq X2: E2; gen_eq X1: E1.

sets_let X finds the first let-expression in the goal and names its body X. sets_eq_let X is similar, except that it generates an explicit equality. Tactics sets_let X in H and sets_eq_let X in H allow specifying a particular hypothesis (by default, the first one that contains a let is considered).
Known limitation: it does not seem possible to support naming of multiple let-in constructs inside a term, from ltac.

Ltac sets_let_base tac :=
match goal with
| context[let _ := ?E in _] ⇒ tac E; cbv zeta
| H: context[let _ := ?E in _] _tac E; cbv zeta in H
end.

Ltac sets_let_in_base H tac :=
match type of H with context[let _ := ?E in _] ⇒
tac E; cbv zeta in H end.

Tactic Notation "sets_let" ident(X) :=
sets_let_base ltac:(fun Esets X: E).
Tactic Notation "sets_let" ident(X) "in" hyp(H) :=
sets_let_in_base H ltac:(fun Esets X: E).
Tactic Notation "sets_eq_let" ident(X) :=
sets_let_base ltac:(fun Esets_eq X: E).
Tactic Notation "sets_eq_let" ident(X) "in" hyp(H) :=
sets_let_in_base H ltac:(fun Esets_eq X: E).

(* ********************************************************************** *)

# Rewriting

rewrites E is similar to rewrite except that it supports the rm directives to clear hypotheses on the fly, and that it supports a list of arguments in the form rewrites (>> E1 E2 E3) to indicate that forwards should be invoked first before rewrites is called.

Ltac rewrites_base E cont :=
match type of E with
| List.list Boxerforwards_then E cont
| _cont E; fast_rm_inside E
end.

Tactic Notation "rewrites" constr(E) :=
rewrites_base E ltac:(fun Mrewrite M ).
Tactic Notation "rewrites" constr(E) "in" hyp(H) :=
rewrites_base E ltac:(fun Mrewrite M in H).
Tactic Notation "rewrites" constr(E) "in" "*" :=
rewrites_base E ltac:(fun Mrewrite M in *).
Tactic Notation "rewrites" "" constr(E) :=
rewrites_base E ltac:(fun Mrewrite M ).
Tactic Notation "rewrites" "" constr(E) "in" hyp(H) :=
rewrites_base E ltac:(fun Mrewrite M in H).
Tactic Notation "rewrites" "" constr(E) "in" "*" :=
rewrites_base E ltac:(fun Mrewrite M in *).

(* TODO: extend tactics below to use rewrites *)

rewrite_all E iterates version of rewrite E as long as possible. Warning: this tactic can easily get into an infinite loop. Syntax for rewriting from right to left and/or into an hypothese is similar to the one of rewrite.

Tactic Notation "rewrite_all" constr(E) :=
repeat rewrite E.
Tactic Notation "rewrite_all" "" constr(E) :=
repeat rewrite E.
Tactic Notation "rewrite_all" constr(E) "in" ident(H) :=
repeat rewrite E in H.
Tactic Notation "rewrite_all" "" constr(E) "in" ident(H) :=
repeat rewrite E in H.
Tactic Notation "rewrite_all" constr(E) "in" "*" :=
repeat rewrite E in *.
Tactic Notation "rewrite_all" "" constr(E) "in" "*" :=
repeat rewrite E in *.

asserts_rewrite E asserts that an equality E holds (generating a corresponding subgoal) and rewrite it straight away in the current goal. It avoids giving a name to the equality and later clearing it. Syntax for rewriting from right to left and/or into an hypothese is similar to the one of rewrite. Note: the tactic replaces plays a similar role.

Ltac asserts_rewrite_tactic E action :=
let EQ := fresh in (assert (EQ : E);
[ idtac | action EQ; clear EQ ]).

Tactic Notation "asserts_rewrite" constr(E) :=
asserts_rewrite_tactic E ltac:(fun EQrewrite EQ).
Tactic Notation "asserts_rewrite" "" constr(E) :=
asserts_rewrite_tactic E ltac:(fun EQrewrite EQ).
Tactic Notation "asserts_rewrite" constr(E) "in" hyp(H) :=
asserts_rewrite_tactic E ltac:(fun EQrewrite EQ in H).
Tactic Notation "asserts_rewrite" "" constr(E) "in" hyp(H) :=
asserts_rewrite_tactic E ltac:(fun EQrewrite EQ in H).
Tactic Notation "asserts_rewrite" constr(E) "in" "*" :=
asserts_rewrite_tactic E ltac:(fun EQrewrite EQ in *).
Tactic Notation "asserts_rewrite" "" constr(E) "in" "*" :=
asserts_rewrite_tactic E ltac:(fun EQrewrite EQ in *).

cuts_rewrite E is the same as asserts_rewrite E except that subgoals are permuted.

Ltac cuts_rewrite_tactic E action :=
let EQ := fresh in (cuts EQ: E;
[ action EQ; clear EQ | idtac ]).

Tactic Notation "cuts_rewrite" constr(E) :=
cuts_rewrite_tactic E ltac:(fun EQrewrite EQ).
Tactic Notation "cuts_rewrite" "" constr(E) :=
cuts_rewrite_tactic E ltac:(fun EQrewrite EQ).
Tactic Notation "cuts_rewrite" constr(E) "in" hyp(H) :=
cuts_rewrite_tactic E ltac:(fun EQrewrite EQ in H).
Tactic Notation "cuts_rewrite" "" constr(E) "in" hyp(H) :=
cuts_rewrite_tactic E ltac:(fun EQrewrite EQ in H).

rewrite_except H EQ rewrites equality EQ everywhere but in hypothesis H. Mainly useful for other tactics.

Ltac rewrite_except H EQ :=
let K := fresh in let T := type of H in
set (K := T) in H;
rewrite EQ in *; unfold K in H; clear K.

rewrites E at K applies when E is of the form T1 = T2 rewrites the equality E at the K-th occurence of T1 in the current goal. Syntaxes rewrites E at K and rewrites E at K in H are also available.

Tactic Notation "rewrites" constr(E) "at" constr(K) :=
match type of E with ?T1 = ?T2
ltac_action_at K of T1 do (rewrites E) end.
Tactic Notation "rewrites" "" constr(E) "at" constr(K) :=
match type of E with ?T1 = ?T2
ltac_action_at K of T2 do (rewrites E) end.
Tactic Notation "rewrites" constr(E) "at" constr(K) "in" hyp(H) :=
match type of E with ?T1 = ?T2
ltac_action_at K of T1 in H do (rewrites E in H) end.
Tactic Notation "rewrites" "" constr(E) "at" constr(K) "in" hyp(H) :=
match type of E with ?T1 = ?T2
ltac_action_at K of T2 in H do (rewrites E in H) end.

(* ---------------------------------------------------------------------- *)

## Replace

replaces E with F is the same as replace E with F except that the equality E = F is generated as first subgoal. Syntax replaces E with F in H is also available. Note that contrary to replace, replaces does not try to solve the equality by assumption. Note: replaces E with F is similar to asserts_rewrite (E = F).

Tactic Notation "replaces" constr(E) "with" constr(F) :=
let T := fresh in assert (T: E = F); [ | replace E with F; clear T ].

Tactic Notation "replaces" constr(E) "with" constr(F) "in" hyp(H) :=
let T := fresh in assert (T: E = F); [ | replace E with F in H; clear T ].

replaces E at K with F replaces the K-th occurence of E with F in the current goal. Syntax replaces E at K with F in H is also available.

Tactic Notation "replaces" constr(E) "at" constr(K) "with" constr(F) :=
let T := fresh in assert (T: E = F); [ | rewrites T at K; clear T ].

Tactic Notation "replaces" constr(E) "at" constr(K) "with" constr(F) "in" hyp(H) :=
let T := fresh in assert (T: E = F); [ | rewrites T at K in H; clear T ].

(* ---------------------------------------------------------------------- *)

## Change

changes is like change except that it does not silently fail to perform its task. (Note that, changes is implemented using rewrite, meaning that it might perform additional beta-reductions compared with the original change tactic.
(* TODO: support "changes (E1 = E2)" *)

Tactic Notation "changes" constr(E1) "with" constr(E2) "in" hyp(H) :=
asserts_rewrite (E1 = E2) in H; [ reflexivity | ].

Tactic Notation "changes" constr(E1) "with" constr(E2) :=
asserts_rewrite (E1 = E2); [ reflexivity | ].

Tactic Notation "changes" constr(E1) "with" constr(E2) "in" "*" :=
asserts_rewrite (E1 = E2) in *; [ reflexivity | ].

(* ---------------------------------------------------------------------- *)

## Renaming

renames X1 to Y1, ..., XN to YN is a shorthand for a sequence of renaming operations rename Xi into Yi.

Tactic Notation "renames" ident(X1) "to" ident(Y1) :=
rename X1 into Y1.
Tactic Notation "renames" ident(X1) "to" ident(Y1) ","
ident(X2) "to" ident(Y2) :=
renames X1 to Y1; renames X2 to Y2.
Tactic Notation "renames" ident(X1) "to" ident(Y1) ","
ident(X2) "to" ident(Y2) "," ident(X3) "to" ident(Y3) :=
renames X1 to Y1; renames X2 to Y2, X3 to Y3.
Tactic Notation "renames" ident(X1) "to" ident(Y1) ","
ident(X2) "to" ident(Y2) "," ident(X3) "to" ident(Y3) ","
ident(X4) "to" ident(Y4) :=
renames X1 to Y1; renames X2 to Y2, X3 to Y3, X4 to Y4.
Tactic Notation "renames" ident(X1) "to" ident(Y1) ","
ident(X2) "to" ident(Y2) "," ident(X3) "to" ident(Y3) ","
ident(X4) "to" ident(Y4) "," ident(X5) "to" ident(Y5) :=
renames X1 to Y1; renames X2 to Y2, X3 to Y3, X4 to Y4, X5 to Y5.
Tactic Notation "renames" ident(X1) "to" ident(Y1) ","
ident(X2) "to" ident(Y2) "," ident(X3) "to" ident(Y3) ","
ident(X4) "to" ident(Y4) "," ident(X5) "to" ident(Y5) ","
ident(X6) "to" ident(Y6) :=
renames X1 to Y1; renames X2 to Y2, X3 to Y3, X4 to Y4, X5 to Y5, X6 to Y6.

(* ---------------------------------------------------------------------- *)

## Unfolding

unfolds unfolds the head definition in the goal, i.e., if the goal has form P x1 ... xN then it calls unfold P. If the goal is an equality, it tries to unfold the head constant on the left-hand side, and otherwise tries on the right-hand side. If the goal is a product, it calls intros first. warning: this tactic is overriden in LibReflect.

Ltac apply_to_head_of E cont :=
let go E :=
let P := get_head E in cont P in
match E with
| _,_ ⇒ intros; apply_to_head_of E cont
| ?A = ?Bfirst [ go A | go B ]
| ?Ago A
end.

Ltac unfolds_base :=
match goal with ?G
apply_to_head_of G ltac:(fun Punfold P) end.

Tactic Notation "unfolds" :=
unfolds_base.

unfolds in H unfolds the head definition of hypothesis H, i.e., if H has type P x1 ... xN then it calls unfold P in H.

Ltac unfolds_in_base H :=
match type of H with ?G
apply_to_head_of G ltac:(fun Punfold P in H) end.

Tactic Notation "unfolds" "in" hyp(H) :=
unfolds_in_base H.

unfolds in H1,H2,..,HN allows unfolding the head constant in several hypotheses at once.

Tactic Notation "unfolds" "in" hyp(H1) hyp(H2) :=
unfolds in H1; unfolds in H2.
Tactic Notation "unfolds" "in" hyp(H1) hyp(H2) hyp(H3) :=
unfolds in H1; unfolds in H2 H3.
Tactic Notation "unfolds" "in" hyp(H1) hyp(H2) hyp(H3) hyp(H4) :=
unfolds in H1; unfolds in H2 H3 H4.

unfolds P1,..,PN is a shortcut for unfold P1,..,PN in *.

Tactic Notation "unfolds" constr(F1) :=
unfold F1 in *.
Tactic Notation "unfolds" constr(F1) "," constr(F2) :=
unfold F1,F2 in *.
Tactic Notation "unfolds" constr(F1) "," constr(F2)
"," constr(F3) :=
unfold F1,F2,F3 in *.
Tactic Notation "unfolds" constr(F1) "," constr(F2)
"," constr(F3) "," constr(F4) :=
unfold F1,F2,F3,F4 in *.
Tactic Notation "unfolds" constr(F1) "," constr(F2)
"," constr(F3) "," constr(F4) "," constr(F5) :=
unfold F1,F2,F3,F4,F5 in *.
Tactic Notation "unfolds" constr(F1) "," constr(F2)
"," constr(F3) "," constr(F4) "," constr(F5) "," constr(F6) :=
unfold F1,F2,F3,F4,F5,F6 in *.
Tactic Notation "unfolds" constr(F1) "," constr(F2)
"," constr(F3) "," constr(F4) "," constr(F5)
"," constr(F6) "," constr(F7) :=
unfold F1,F2,F3,F4,F5,F6,F7 in *.
Tactic Notation "unfolds" constr(F1) "," constr(F2)
"," constr(F3) "," constr(F4) "," constr(F5)
"," constr(F6) "," constr(F7) "," constr(F8) :=
unfold F1,F2,F3,F4,F5,F6,F7,F8 in *.

folds P1,..,PN is a shortcut for fold P1 in *; ..; fold PN in *.

Tactic Notation "folds" constr(H) :=
fold H in *.
Tactic Notation "folds" constr(H1) "," constr(H2) :=
folds H1; folds H2.
Tactic Notation "folds" constr(H1) "," constr(H2) "," constr(H3) :=
folds H1; folds H2; folds H3.
Tactic Notation "folds" constr(H1) "," constr(H2) "," constr(H3)
"," constr(H4) :=
folds H1; folds H2; folds H3; folds H4.
Tactic Notation "folds" constr(H1) "," constr(H2) "," constr(H3)
"," constr(H4) "," constr(H5) :=
folds H1; folds H2; folds H3; folds H4; folds H5.

(* ---------------------------------------------------------------------- *)

## Simplification

simpls is a shortcut for simpl in *.

Tactic Notation "simpls" :=
simpl in *.

simpls P1,..,PN is a shortcut for simpl P1 in *; ..; simpl PN in *.

Tactic Notation "simpls" constr(F1) :=
simpl F1 in *.
Tactic Notation "simpls" constr(F1) "," constr(F2) :=
simpls F1; simpls F2.
Tactic Notation "simpls" constr(F1) "," constr(F2)
"," constr(F3) :=
simpls F1; simpls F2; simpls F3.
Tactic Notation "simpls" constr(F1) "," constr(F2)
"," constr(F3) "," constr(F4) :=
simpls F1; simpls F2; simpls F3; simpls F4.

unsimpl E replaces all occurence of X by E, where X is the result which the tactic simpl would give when applied to E. It is useful to undo what simpl has simplified too far.

Tactic Notation "unsimpl" constr(E) :=
let F := (eval simpl in E) in change F with E.

unsimpl E in H is similar to unsimpl E but it applies inside a particular hypothesis H.

Tactic Notation "unsimpl" constr(E) "in" hyp(H) :=
let F := (eval simpl in E) in change F with E in H.

unsimpl E in * applies unsimpl E everywhere possible. unsimpls E is a synonymous.

Tactic Notation "unsimpl" constr(E) "in" "*" :=
let F := (eval simpl in E) in change F with E in *.
Tactic Notation "unsimpls" constr(E) :=
unsimpl E in *.

nosimpl t protects the Coq termt against some forms of simplification. See Gonthier's work for details on this trick.

Notation "'nosimpl' t" := (match tt with ttt end)
(at level 10).

(* ---------------------------------------------------------------------- *)

## Evaluation

Tactic Notation "hnfs" := hnf in *.

(* ---------------------------------------------------------------------- *)

## Substitution

substs does the same as subst, except that it does not fail when there are circular equalities in the context.

Tactic Notation "substs" :=
repeat (match goal with H: ?x = ?y _
first [ subst x | subst y ] end).

Implementation of substs below, which allows to call subst on all the hypotheses that lie beyond a given position in the proof context.

Ltac substs_below limit :=
match goal with H: ?T _
match T with
| limitidtac
| ?x = ?y
first [ subst x; substs_below limit
| subst y; substs_below limit
| generalizes H; substs_below limit; intro ]
end end.

substs below body E applies subst on all equalities that appear in the context below the first hypothesis whose body is E. If there is no such hypothesis in the context, it is equivalent to subst. For instance, if H is an hypothesis, then substs below H will substitute equalities below hypothesis H.

Tactic Notation "substs" "below" "body" constr(M) :=
substs_below M.

substs below H applies subst on all equalities that appear in the context below the hypothesis named H. Note that the current implementation is technically incorrect since it will confuse different hypotheses with the same body.

Tactic Notation "substs" "below" hyp(H) :=
match type of H with ?Msubsts below body M end.

subst_hyp H substitutes the equality contained in the first hypothesis from the context.

Ltac intro_subst_hyp := fail. (* definition further on *)

subst_hyp H substitutes the equality contained in H.

Ltac subst_hyp_base H :=
match type of H with
| (_,_,_,_,_) = (_,_,_,_,_) ⇒ injection H; clear H; do 4 intro_subst_hyp
| (_,_,_,_) = (_,_,_,_) ⇒ injection H; clear H; do 4 intro_subst_hyp
| (_,_,_) = (_,_,_) ⇒ injection H; clear H; do 3 intro_subst_hyp
| (_,_) = (_,_) ⇒ injection H; clear H; do 2 intro_subst_hyp
| ?x = ?xclear H
| ?x = ?yfirst [ subst x | subst y ]
end.

Tactic Notation "subst_hyp" hyp(H) := subst_hyp_base H.

Ltac intro_subst_hyp ::=
let H := fresh "TEMP" in intros H; subst_hyp H.

intro_subst is a shorthand for intro H; subst_hyp H: it introduces and substitutes the equality at the head of the current goal.

Tactic Notation "intro_subst" :=
let H := fresh "TEMP" in intros H; subst_hyp H.

subst_local substitutes all local definition from the context

Ltac subst_local :=
repeat match goal with H:=_ _subst H end.

subst_eq E takes an equality x = t and replace x with t everywhere in the goal

Ltac subst_eq_base E :=
let H := fresh "TEMP" in lets H: E; subst_hyp H.

Tactic Notation "subst_eq" constr(E) :=
subst_eq_base E.

(* ---------------------------------------------------------------------- *)

## Tactics to work with proof irrelevance

Require Import ProofIrrelevance.

pi_rewrite E replaces E of type Prop with a fresh unification variable, and is thus a practical way to exploit proof irrelevance, without writing explicitly rewrite (proof_irrelevance E E'). Particularly useful when E' is a big expression.

Ltac pi_rewrite_base E rewrite_tac :=
let E' := fresh in let T := type of E in evar (E':T);
rewrite_tac (@proof_irrelevance _ E E'); subst E'.

Tactic Notation "pi_rewrite" constr(E) :=
pi_rewrite_base E ltac:(fun Xrewrite X).
Tactic Notation "pi_rewrite" constr(E) "in" hyp(H) :=
pi_rewrite_base E ltac:(fun Xrewrite X in H).

(* ---------------------------------------------------------------------- *)

## Proving equalities

Note: current implementation only supports up to arity 5
fequal is a variation on f_equal which has a better behaviour on equalities between n-ary tuples.

Ltac fequal_base :=
let go := f_equal; [ fequal_base | ] in
match goal with
| (_,_,_) = (_,_,_) ⇒ go
| (_,_,_,_) = (_,_,_,_) ⇒ go
| (_,_,_,_,_) = (_,_,_,_,_) ⇒ go
| (_,_,_,_,_,_) = (_,_,_,_,_,_) ⇒ go
| _f_equal
end.

Tactic Notation "fequal" :=
fequal_base.

fequals is the same as fequal except that it tries and solve all trivial subgoals, using reflexivity and congruence (as well as the proof-irrelevance principle). fequals applies to goals of the form f x1 .. xN = f y1 .. yN and produces some subgoals of the form xi = yi).

Ltac fequal_post :=
first [ reflexivity | congruence | apply proof_irrelevance | idtac ].

Tactic Notation "fequals" :=
fequal; fequal_post.

fequals_rec calls fequals recursively. It is equivalent to repeat (progress fequals).

Tactic Notation "fequals_rec" :=
repeat (progress fequals).

(* ********************************************************************** *)

# Inversion

(* ---------------------------------------------------------------------- *)

## Basic inversion

invert keep H is same to inversion H except that it puts all the facts obtained in the goal. The keyword keep means that the hypothesis H should not be removed.

Tactic Notation "invert" "keep" hyp(H) :=
pose ltac_mark; inversion H; gen_until_mark.

invert keep H as X1 .. XN is the same as inversion H as ... except that only hypotheses which are not variable need to be named explicitely, in a similar fashion as introv is used to name only hypotheses.

Tactic Notation "invert" "keep" hyp(H) "as" simple_intropattern(I1) :=
invert keep H; introv I1.
Tactic Notation "invert" "keep" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) :=
invert keep H; introv I1 I2.
Tactic Notation "invert" "keep" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) :=
invert keep H; introv I1 I2 I3.

invert H is same to inversion H except that it puts all the facts obtained in the goal and clears hypothesis H. In other words, it is equivalent to invert keep H; clear H.

Tactic Notation "invert" hyp(H) :=
invert keep H; clear H.

invert H as X1 .. XN is the same as invert keep H as X1 .. XN but it also clears hypothesis H.

Tactic Notation "invert_tactic" hyp(H) tactic(tac) :=
let H' := fresh in rename H into H'; tac H'; clear H'.
Tactic Notation "invert" hyp(H) "as" simple_intropattern(I1) :=
invert_tactic H (fun Hinvert keep H as I1).
Tactic Notation "invert" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) :=
invert_tactic H (fun Hinvert keep H as I1 I2).
Tactic Notation "invert" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) :=
invert_tactic H (fun Hinvert keep H as I1 I2 I3).

(* ---------------------------------------------------------------------- *)

## Inversion with substitution

Our inversion tactics is able to get rid of dependent equalities generated by inversion, using proof irrelevance.

(* --we do not import Eqdep because it imports nasty hints automatically
Require Import Eqdep. *)

Axiom inj_pair2 : (* is in fact derivable from the axioms in LibAxiom.v *)
(U : Type) (P : U Type) (p : U) (x y : P p),
existT P p x = existT P p y x = y.
(* Proof using. apply Eqdep.EqdepTheory.inj_pair2. Qed.*)

Ltac inverts_tactic H i1 i2 i3 i4 i5 i6 :=
let rec go i1 i2 i3 i4 i5 i6 :=
match goal with
| (ltac_Mark _) ⇒ intros _
| (?x = ?y _) ⇒ let H := fresh in intro H;
first [ subst x | subst y ];
go i1 i2 i3 i4 i5 i6
| (existT ?P ?p ?x = existT ?P ?p ?y _) ⇒
let H := fresh in intro H;
generalize (@inj_pair2 _ P p x y H);
clear H; go i1 i2 i3 i4 i5 i6
| (?P ?Q) ⇒ i1; go i2 i3 i4 i5 i6 ltac:(intro)
| (_, _) ⇒ intro; go i1 i2 i3 i4 i5 i6
end in
generalize ltac_mark; invert keep H; go i1 i2 i3 i4 i5 i6;
unfold eq' in *.

inverts keep H is same to invert keep H except that it applies subst to all the equalities generated by the inversion.

Tactic Notation "inverts" "keep" hyp(H) :=
inverts_tactic H ltac:(intro) ltac:(intro) ltac:(intro)
ltac:(intro) ltac:(intro) ltac:(intro).

inverts keep H as X1 .. XN is the same as invert keep H as X1 .. XN except that it applies subst to all the equalities generated by the inversion

Tactic Notation "inverts" "keep" hyp(H) "as" simple_intropattern(I1) :=
inverts_tactic H ltac:(intros I1)
ltac:(intro) ltac:(intro) ltac:(intro) ltac:(intro) ltac:(intro).
Tactic Notation "inverts" "keep" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) :=
inverts_tactic H ltac:(intros I1) ltac:(intros I2)
ltac:(intro) ltac:(intro) ltac:(intro) ltac:(intro).
Tactic Notation "inverts" "keep" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) :=
inverts_tactic H ltac:(intros I1) ltac:(intros I2) ltac:(intros I3)
ltac:(intro) ltac:(intro) ltac:(intro).
Tactic Notation "inverts" "keep" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4) :=
inverts_tactic H ltac:(intros I1) ltac:(intros I2) ltac:(intros I3)
ltac:(intros I4) ltac:(intro) ltac:(intro).
Tactic Notation "inverts" "keep" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4)
simple_intropattern(I5) :=
inverts_tactic H ltac:(intros I1) ltac:(intros I2) ltac:(intros I3)
ltac:(intros I4) ltac:(intros I5) ltac:(intro).
Tactic Notation "inverts" "keep" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4)
simple_intropattern(I5) simple_intropattern(I6) :=
inverts_tactic H ltac:(intros I1) ltac:(intros I2) ltac:(intros I3)
ltac:(intros I4) ltac:(intros I5) ltac:(intros I6).

inverts H is same to inverts keep H except that it clears hypothesis H.

Tactic Notation "inverts" hyp(H) :=
inverts keep H; clear H.

inverts H as X1 .. XN is the same as inverts keep H as X1 .. XN but it also clears the hypothesis H.

Tactic Notation "inverts_tactic" hyp(H) tactic(tac) :=
let H' := fresh in rename H into H'; tac H'; clear H'.
Tactic Notation "inverts" hyp(H) "as" simple_intropattern(I1) :=
invert_tactic H (fun Hinverts keep H as I1).
Tactic Notation "inverts" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) :=
invert_tactic H (fun Hinverts keep H as I1 I2).
Tactic Notation "inverts" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) :=
invert_tactic H (fun Hinverts keep H as I1 I2 I3).
Tactic Notation "inverts" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4) :=
invert_tactic H (fun Hinverts keep H as I1 I2 I3 I4).
Tactic Notation "inverts" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4)
simple_intropattern(I5) :=
invert_tactic H (fun Hinverts keep H as I1 I2 I3 I4 I5).
Tactic Notation "inverts" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4)
simple_intropattern(I5) simple_intropattern(I6) :=
invert_tactic H (fun Hinverts keep H as I1 I2 I3 I4 I5 I6).

inverts H as performs an inversion on hypothesis H, substitutes generated equalities, and put in the goal the other freshly-created hypotheses, for the user to name explicitly. inverts keep H as is the same except that it does not clear H. TODO: reimplement inverts above using this one

Ltac inverts_as_tactic H :=
let rec go tt :=
match goal with
| (ltac_Mark _) ⇒ intros _
| (?x = ?y _) ⇒ let H := fresh "TEMP" in intro H;
first [ subst x | subst y ];
go tt
| (existT ?P ?p ?x = existT ?P ?p ?y _) ⇒
let H := fresh in intro H;
generalize (@inj_pair2 _ P p x y H);
clear H; go tt
| (_, _) ⇒
intro; let H := get_last_hyp tt in mark_to_generalize H; go tt
end in
pose ltac_mark; inversion H;
generalize ltac_mark; gen_until_mark;
go tt; gen_to_generalize; unfolds ltac_to_generalize;
unfold eq' in *.

Tactic Notation "inverts" "keep" hyp(H) "as" :=
inverts_as_tactic H.

Tactic Notation "inverts" hyp(H) "as" :=
inverts_as_tactic H; clear H.

Tactic Notation "inverts" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4)
simple_intropattern(I5) simple_intropattern(I6) simple_intropattern(I7) :=
inverts H as; introv I1 I2 I3 I4 I5 I6 I7.
Tactic Notation "inverts" hyp(H) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4)
simple_intropattern(I5) simple_intropattern(I6) simple_intropattern(I7)
simple_intropattern(I8) :=
inverts H as; introv I1 I2 I3 I4 I5 I6 I7 I8.

lets_inverts E as I1 .. IN is intuitively equivalent to inverts E, with the difference that it applies to any expression and not just to the name of an hypothesis.

Ltac lets_inverts_base E cont :=
let H := fresh "TEMP" in lets H: E; try cont H.

Tactic Notation "lets_inverts" constr(E) :=
lets_inverts_base E ltac:(fun Hinverts H).
Tactic Notation "lets_inverts" constr(E) "as" simple_intropattern(I1) :=
lets_inverts_base E ltac:(fun Hinverts H as I1).
Tactic Notation "lets_inverts" constr(E) "as" simple_intropattern(I1)
simple_intropattern(I2) :=
lets_inverts_base E ltac:(fun Hinverts H as I1 I2).
Tactic Notation "lets_inverts" constr(E) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) :=
lets_inverts_base E ltac:(fun Hinverts H as I1 I2 I3).
Tactic Notation "lets_inverts" constr(E) "as" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) simple_intropattern(I4) :=
lets_inverts_base E ltac:(fun Hinverts H as I1 I2 I3 I4).

(* ---------------------------------------------------------------------- *)

## Injection with substitution

Underlying implementation of injects

Ltac injects_tactic H :=
let rec go _ :=
match goal with
| (ltac_Mark _) ⇒ intros _
| (?x = ?y _) ⇒ let H := fresh in intro H;
first [ subst x | subst y | idtac ];
go tt
end in
generalize ltac_mark; injection H; go tt.

injects keep H takes an hypothesis H of the form C a1 .. aN = C b1 .. bN and substitute all equalities ai = bi that have been generated.

Tactic Notation "injects" "keep" hyp(H) :=
injects_tactic H.

injects H is similar to injects keep H but clears the hypothesis H.

Tactic Notation "injects" hyp(H) :=
injects_tactic H; clear H.

inject H as X1 .. XN is the same as injection followed by intros X1 .. XN

Tactic Notation "inject" hyp(H) :=
injection H.
Tactic Notation "inject" hyp(H) "as" ident(X1) :=
injection H; intros X1.
Tactic Notation "inject" hyp(H) "as" ident(X1) ident(X2) :=
injection H; intros X1 X2.
Tactic Notation "inject" hyp(H) "as" ident(X1) ident(X2) ident(X3) :=
injection H; intros X1 X2 X3.
Tactic Notation "inject" hyp(H) "as" ident(X1) ident(X2) ident(X3)
ident(X4) :=
injection H; intros X1 X2 X3 X4.
Tactic Notation "inject" hyp(H) "as" ident(X1) ident(X2) ident(X3)
ident(X4) ident(X5) :=
injection H; intros X1 X2 X3 X4 X5.

(* ---------------------------------------------------------------------- *)

## Inversion and injection with substitution —rough implementation

The tactics inversions and injections provided in this section are similar to inverts and injects except that they perform substitution on all equalities from the context and not only the ones freshly generated. The counterpart is that they have simpler implementations.
inversions keep H is the same as inversions H but it does not clear hypothesis H.

Tactic Notation "inversions" "keep" hyp(H) :=
inversion H; subst.

inversions H is a shortcut for inversion H followed by subst and clear H. It is a rough implementation of inverts keep H which behave badly when the proof context already contains equalities. It is provided in case the better implementation turns out to be too slow.

Tactic Notation "inversions" hyp(H) :=
inversion H; subst; clear H.

injections keep H is the same as injection H followed by intros and subst. It is a rough implementation of injects keep H which behave badly when the proof context already contains equalities, or when the goal starts with a forall or an implication.

Tactic Notation "injections" "keep" hyp(H) :=
injection H; intros; subst.

injections H is the same as injection H followed by intros and clear H and subst. It is a rough implementation of injects keep H which behave badly when the proof context already contains equalities, or when the goal starts with a forall or an implication.

Tactic Notation "injections" "keep" hyp(H) :=
injection H; clear H; intros; subst.

(* ---------------------------------------------------------------------- *)

## Case analysis

cases is similar to case_eq E except that it generates the equality in the context and not in the goal, and generates the equality the other way round. The syntax cases E as H allows specifying the name H of that hypothesis.

Tactic Notation "cases" constr(E) "as" ident(H) :=
let X := fresh "TEMP" in
set (X := E) in *; def_to_eq_sym X H E;
destruct X.

Tactic Notation "cases" constr(E) :=
let H := fresh "Eq" in cases E as H.

case_if_post is to be defined later as a tactic to clean up goals. By defaults, it looks for obvious contradictions. Currently, this tactic is extended in LibReflect to clean up boolean propositions.

Ltac case_if_post := tryfalse.

case_if looks for a pattern of the form if ?B then ?E1 else ?E2 in the goal, and perform a case analysis on B by calling destruct B. Subgoals containing a contradiction are discarded. case_if looks in the goal first, and otherwise in the first hypothesis that contains and if statement. case_if in H can be used to specify which hypothesis to consider. Syntaxes case_if as Eq and case_if in H as Eq allows to name the hypothesis coming from the case analysis.

Ltac case_if_on_tactic_core E Eq :=
match type of E with
| {_}+{_} ⇒ destruct E as [Eq | Eq]
| _let X := fresh in
sets_eq X Eq: E;
destruct X
end.

Ltac case_if_on_tactic E Eq :=
case_if_on_tactic_core E Eq; case_if_post.

Tactic Notation "case_if_on" constr(E) "as" simple_intropattern(Eq) :=
case_if_on_tactic E Eq.

Tactic Notation "case_if" "as" simple_intropattern(Eq) :=
match goal with
| context [if ?B then _ else _] ⇒ case_if_on B as Eq
| K: context [if ?B then _ else _] _case_if_on B as Eq
end.

Tactic Notation "case_if" "in" hyp(H) "as" simple_intropattern(Eq) :=
match type of H with context [if ?B then _ else _] ⇒
case_if_on B as Eq end.

Tactic Notation "case_if" :=
let Eq := fresh in case_if as Eq.

Tactic Notation "case_if" "in" hyp(H) :=
let Eq := fresh in case_if in H as Eq.

cases_if is similar to case_if with two main differences: if it creates an equality of the form x = y and then substitutes it in the goal

Ltac cases_if_on_tactic_core E Eq :=
match type of E with
| {_}+{_} ⇒ destruct E as [Eq|Eq]; try subst_hyp Eq
| _let X := fresh in
sets_eq X Eq: E;
destruct X
end.

Ltac cases_if_on_tactic E Eq :=
cases_if_on_tactic_core E Eq; tryfalse; case_if_post.

Tactic Notation "cases_if_on" constr(E) "as" simple_intropattern(Eq) :=
cases_if_on_tactic E Eq.

Tactic Notation "cases_if" "as" simple_intropattern(Eq) :=
match goal with
| context [if ?B then _ else _] ⇒ cases_if_on B as Eq
| K: context [if ?B then _ else _] _cases_if_on B as Eq
end.

Tactic Notation "cases_if" "in" hyp(H) "as" simple_intropattern(Eq) :=
match type of H with context [if ?B then _ else _] ⇒
cases_if_on B as Eq end.

Tactic Notation "cases_if" :=
let Eq := fresh in cases_if as Eq.

Tactic Notation "cases_if" "in" hyp(H) :=
let Eq := fresh in cases_if in H as Eq.

case_ifs is like repeat case_if

Ltac case_ifs_core :=
repeat case_if.

Tactic Notation "case_ifs" :=
case_ifs_core.

destruct_if looks for a pattern of the form if ?B then ?E1 else ?E2 in the goal, and perform a case analysis on B by calling destruct B. It looks in the goal first, and otherwise in the first hypothesis that contains and if statement.

Ltac destruct_if_post := tryfalse.

Tactic Notation "destruct_if"
"as" simple_intropattern(Eq1) simple_intropattern(Eq2) :=
match goal with
| context [if ?B then _ else _] ⇒ destruct B as [Eq1|Eq2]
| K: context [if ?B then _ else _] _destruct B as [Eq1|Eq2]
end;
destruct_if_post.

Tactic Notation "destruct_if" "in" hyp(H)
"as" simple_intropattern(Eq1) simple_intropattern(Eq2) :=
match type of H with context [if ?B then _ else _] ⇒
destruct B as [Eq1|Eq2] end;
destruct_if_post.

Tactic Notation "destruct_if" "as" simple_intropattern(Eq) :=
destruct_if as Eq Eq.
Tactic Notation "destruct_if" "in" hyp(H) "as" simple_intropattern(Eq) :=
destruct_if in H as Eq Eq.

Tactic Notation "destruct_if" :=
let Eq := fresh "C" in destruct_if as Eq Eq.
Tactic Notation "destruct_if" "in" hyp(H) :=
let Eq := fresh "C" in destruct_if in H as Eq Eq.

BROKEN since v8.5beta2.
destruct_head_match performs a case analysis on the argument of the head pattern matching when the goal has the form match ?E with ... or match ?E with ... = _ or _ = match ?E with .... Due to the limits of Ltac, this tactic will not fail if a match does not occur. Instead, it might perform a case analysis on an unspecified subterm from the goal. Warning: experimental.

Ltac find_head_match T :=
match T with context [?E] ⇒
match T with
| Efail 1
| _constr:(E)
end
end.

Ltac destruct_head_match_core cont :=
match goal with
| ?T1 = ?T2first [ let E := find_head_match T1 in cont E
| let E := find_head_match T2 in cont E ]
| ?T1let E := find_head_match T1 in cont E
end;
destruct_if_post.

Tactic Notation "destruct_head_match" "as" simple_intropattern(I) :=
destruct_head_match_core ltac:(fun Edestruct E as I).

Tactic Notation "destruct_head_match" :=
destruct_head_match_core ltac:(fun Edestruct E).

(**--provided for compatibility with remember *)

cases' E is similar to case_eq E except that it generates the equality in the context and not in the goal. The syntax cases E as H allows specifying the name H of that hypothesis.

Tactic Notation "cases'" constr(E) "as" ident(H) :=
let X := fresh "TEMP" in
set (X := E) in *; def_to_eq X H E;
destruct X.

Tactic Notation "cases'" constr(E) :=
let x := fresh "Eq" in cases' E as H.

cases_if' is similar to cases_if except that it generates the symmetric equality.

Ltac cases_if_on' E Eq :=
match type of E with
| {_}+{_} ⇒ destruct E as [Eq|Eq]; try subst_hyp Eq
| _let X := fresh in
sets_eq X Eq: E;
destruct X
end; case_if_post.

Tactic Notation "cases_if'" "as" simple_intropattern(Eq) :=
match goal with
| context [if ?B then _ else _] ⇒ cases_if_on' B Eq
| K: context [if ?B then _ else _] _cases_if_on' B Eq
end.

Tactic Notation "cases_if'" :=
let Eq := fresh in cases_if' as Eq.

(* ********************************************************************** *)

# Induction

inductions E is a shorthand for dependent induction E. inductions E gen X1 .. XN is a shorthand for dependent induction E generalizing X1 .. XN.

Require Import Coq.Program.Equality.

Ltac inductions_post :=
unfold eq' in *.

Tactic Notation "inductions" ident(E) :=
dependent induction E; inductions_post.
Tactic Notation "inductions" ident(E) "gen" ident(X1) :=
dependent induction E generalizing X1; inductions_post.
Tactic Notation "inductions" ident(E) "gen" ident(X1) ident(X2) :=
dependent induction E generalizing X1 X2; inductions_post.
Tactic Notation "inductions" ident(E) "gen" ident(X1) ident(X2)
ident(X3) :=
dependent induction E generalizing X1 X2 X3; inductions_post.
Tactic Notation "inductions" ident(E) "gen" ident(X1) ident(X2)
ident(X3) ident(X4) :=
dependent induction E generalizing X1 X2 X3 X4; inductions_post.
Tactic Notation "inductions" ident(E) "gen" ident(X1) ident(X2)
ident(X3) ident(X4) ident(X5) :=
dependent induction E generalizing X1 X2 X3 X4 X5; inductions_post.
Tactic Notation "inductions" ident(E) "gen" ident(X1) ident(X2)
ident(X3) ident(X4) ident(X5) ident(X6) :=
dependent induction E generalizing X1 X2 X3 X4 X5 X6; inductions_post.
Tactic Notation "inductions" ident(E) "gen" ident(X1) ident(X2)
ident(X3) ident(X4) ident(X5) ident(X6) ident(X7) :=
dependent induction E generalizing X1 X2 X3 X4 X5 X6 X7; inductions_post.
Tactic Notation "inductions" ident(E) "gen" ident(X1) ident(X2)
ident(X3) ident(X4) ident(X5) ident(X6) ident(X7) ident(X8) :=
dependent induction E generalizing X1 X2 X3 X4 X5 X6 X7 X8; inductions_post.

induction_wf IH: E X is used to apply the well-founded induction principle, for a given well-founded relation. It applies to a goal PX where PX is a proposition on X. First, it sets up the goal in the form (fun a P a) X, using pattern X, and then it applies the well-founded induction principle instantiated on E, where E is a term of type well_founded R, and R is a binary relation. Syntaxes induction_wf: E X and induction_wf E X.

Tactic Notation "induction_wf" ident(IH) ":" constr(E) ident(X) :=
pattern X; apply (well_founded_ind E); clear X; intros X IH.
Tactic Notation "induction_wf" ":" constr(E) ident(X) :=
let IH := fresh "IH" in induction_wf IH: E X.
Tactic Notation "induction_wf" ":" constr(E) ident(X) :=
induction_wf: E X.

Induction on the height of a derivation: the helper tactic induct_height helps proving the equivalence of the auxiliary judgment that includes a counter for the maximal height (see LibTacticsDemos for an example)

Require Import Compare_dec Omega.

Lemma induct_height_max2 : n1 n2 : nat,
n, n1 < n n2 < n.
Proof using.
intros. destruct (lt_dec n1 n2).
(S n2). omega.
(S n1). omega.
Qed.

Ltac induct_height_step x :=
match goal with
| H: _, _ _
let n := fresh "n" in let y := fresh "x" in
destruct H as [n ?];
forwards (y&?&?): induct_height_max2 n x;
induct_height_step y
| _(S x); eauto
end.

Ltac induct_height := induct_height_step O.

(* ********************************************************************** *)

# Coinduction

Tactic cofixs IH is like cofix IH except that the coinduction hypothesis is tagged in the form IH: COIND P instead of being just IH: P. This helps other tactics clearing the coinduction hypothesis using clear_coind

Definition COIND (P:Prop) := P.

Tactic Notation "cofixs" ident(IH) :=
cofix IH;
match type of IH with ?Pchange P with (COIND P) in IH end.

Tactic clear_coind clears all the coinduction hypotheses, assuming that they have been tagged

Ltac clear_coind :=
repeat match goal with H: COIND _ _clear H end.

Tactic abstracts tac is like abstract tac except that it clears the coinduction hypotheses so that the productivity check will be happy. For example, one can use abstracts omega to obtain the same behavior as omega but with an auxiliary lemma being generated.

Tactic Notation "abstracts" tactic(tac) :=
clear_coind; tac.

(* ********************************************************************** *)

# Decidable equality

decides_equality is the same as decide equality excepts that it is able to unfold definitions at head of the current goal.

Ltac decides_equality_tactic :=
first [ decide equality | progress(unfolds); decides_equality_tactic ].

Tactic Notation "decides_equality" :=
decides_equality_tactic.

(* ********************************************************************** *)

# Equivalence

iff H can be used to prove an equivalence P Q and name H the hypothesis obtained in each case. The syntaxes iff and iff H1 H2 are also available to specify zero or two names. The tactic iff H swaps the two subgoals, i.e., produces (Q -> P) as first subgoal.

Lemma iff_intro_swap : (P Q : Prop),
(Q P) (P Q) (P Q).
Proof using. intuition. Qed.

Tactic Notation "iff" simple_intropattern(H1) simple_intropattern(H2) :=
split; [ intros H1 | intros H2 ].
Tactic Notation "iff" simple_intropattern(H) :=
iff H H.
Tactic Notation "iff" :=
let H := fresh "H" in iff H.

Tactic Notation "iff" "" simple_intropattern(H1) simple_intropattern(H2) :=
apply iff_intro_swap; [ intros H1 | intros H2 ].
Tactic Notation "iff" "" simple_intropattern(H) :=
iff H H.
Tactic Notation "iff" "" :=
let H := fresh "H" in iff H.

(* ********************************************************************** *)

# N-ary Conjunctions and Disjunctions

(* ---------------------------------------------------------------------- *)
N-ary Conjunctions Splitting in Goals
Underlying implementation of splits.

Ltac splits_tactic N :=
match N with
| Ofail
| S Oidtac
| S ?N'split; [| splits_tactic N']
end.

Ltac unfold_goal_until_conjunction :=
match goal with
| _ _idtac
| _progress(unfolds); unfold_goal_until_conjunction
end.

Ltac get_term_conjunction_arity T :=
match T with
| _ _ _ _ _ _ _ _constr:(8)
| _ _ _ _ _ _ _constr:(7)
| _ _ _ _ _ _constr:(6)
| _ _ _ _ _constr:(5)
| _ _ _ _constr:(4)
| _ _ _constr:(3)
| _ _constr:(2)
| _ ?T'get_term_conjunction_arity T'
| _let P := get_head T in
let T' := eval unfold P in T in
match T' with
| Tfail 1
| _get_term_conjunction_arity T'
end
(* todo: warning this can loop... *)
end.

Ltac get_goal_conjunction_arity :=
match goal with ?Tget_term_conjunction_arity T end.

splits applies to a goal of the form (T1 .. TN) and destruct it into N subgoals T1 .. TN. If the goal is not a conjunction, then it unfolds the head definition.

Tactic Notation "splits" :=
unfold_goal_until_conjunction;
let N := get_goal_conjunction_arity in
splits_tactic N.

splits N is similar to splits, except that it will unfold as many definitions as necessary to obtain an N-ary conjunction.

Tactic Notation "splits" constr(N) :=
let N := nat_from_number N in
splits_tactic N.

splits_all will recursively split any conjunction, unfolding definitions when necessary. Warning: this tactic will loop on goals of the form well_founded R. Todo: fix this

Ltac splits_all_base := repeat split.

Tactic Notation "splits_all" :=
splits_all_base.

(* ---------------------------------------------------------------------- *)
N-ary Conjunctions Deconstruction
Underlying implementation of destructs.

Ltac destructs_conjunction_tactic N T :=
match N with
| 2 ⇒ destruct T as [? ?]
| 3 ⇒ destruct T as [? [? ?]] | 4 ⇒ destruct T as [? [? [? ?]]] | 5 ⇒ destruct T as [? [? [? [? ?]]]] | 6 ⇒ destruct T as [? [? [? [? [? ?]]]]] | 7 ⇒ destruct T as [? [? [? [? [? [? ?]]]]]] end.

destructs T allows destructing a term T which is a N-ary conjunction. It is equivalent to destruct T as (H1 .. HN), except that it does not require to manually specify N different names.

Tactic Notation "destructs" constr(T) :=
let TT := type of T in
let N := get_term_conjunction_arity TT in
destructs_conjunction_tactic N T.

destructs N T is equivalent to destruct T as (H1 .. HN), except that it does not require to manually specify N different names. Remark that it is not restricted to N-ary conjunctions.

Tactic Notation "destructs" constr(N) constr(T) :=
let N := nat_from_number N in
destructs_conjunction_tactic N T.

(* ---------------------------------------------------------------------- *)
Proving goals which are N-ary disjunctions
Underlying implementation of branch.

Ltac branch_tactic K N :=
match constr:(K,N) with
| (_,0) ⇒ fail 1
| (0,_) ⇒ fail 1
| (1,1) ⇒ idtac
| (1,_) ⇒ left
| (S ?K', S ?N') ⇒ right; branch_tactic K' N'
end.

Ltac unfold_goal_until_disjunction :=
match goal with
| _ _idtac
| _progress(unfolds); unfold_goal_until_disjunction
end.

Ltac get_term_disjunction_arity T :=
match T with
| _ _ _ _ _ _ _ _constr:(8)
| _ _ _ _ _ _ _constr:(7)
| _ _ _ _ _ _constr:(6)
| _ _ _ _ _constr:(5)
| _ _ _ _constr:(4)
| _ _ _constr:(3)
| _ _constr:(2)
| _ ?T'get_term_disjunction_arity T'
| _let P := get_head T in
let T' := eval unfold P in T in
match T' with
| Tfail 1
| _get_term_disjunction_arity T'
end
end.

Ltac get_goal_disjunction_arity :=
match goal with ?Tget_term_disjunction_arity T end.

branch N applies to a goal of the form P1 ... PK ... PN and leaves the goal PK. It only able to unfold the head definition (if there is one), but for more complex unfolding one should use the tactic branch K of N.

Tactic Notation "branch" constr(K) :=
let K := nat_from_number K in
unfold_goal_until_disjunction;
let N := get_goal_disjunction_arity in
branch_tactic K N.

branch K of N is similar to branch K except that the arity of the disjunction N is given manually, and so this version of the tactic is able to unfold definitions. In other words, applies to a goal of the form P1 ... PK ... PN and leaves the goal PK.

Tactic Notation "branch" constr(K) "of" constr(N) :=
let N := nat_from_number N in
let K := nat_from_number K in
branch_tactic K N.

(* ---------------------------------------------------------------------- *)
N-ary Disjunction Deconstruction
Underlying implementation of branches.

Ltac destructs_disjunction_tactic N T :=
match N with
| 2 ⇒ destruct T as [? | ?]
| 3 ⇒ destruct T as [? | [? | ?]] | 4 ⇒ destruct T as [? | [? | [? | ?]]] | 5 ⇒ destruct T as [? | [? | [? | [? | ?]]]] end.

branches T allows destructing a term T which is a N-ary disjunction. It is equivalent to destruct T as [ H1 | .. | HN ] , and produces N subgoals corresponding to the N possible cases.

Tactic Notation "branches" constr(T) :=
let TT := type of T in
let N := get_term_disjunction_arity TT in
destructs_disjunction_tactic N T.

branches N T is the same as branches T except that the arity is forced to N. This version is useful to unfold definitions on the fly.

Tactic Notation "branches" constr(N) constr(T) :=
let N := nat_from_number N in
destructs_disjunction_tactic N T.

(* ---------------------------------------------------------------------- *)
N-ary Existentials

(* Underlying implementation of . *)

Ltac get_term_existential_arity T :=
match T with
| x1 x2 x3 x4 x5 x6 x7 x8, _constr:(8)
| x1 x2 x3 x4 x5 x6 x7, _constr:(7)
| x1 x2 x3 x4 x5 x6, _constr:(6)
| x1 x2 x3 x4 x5, _constr:(5)
| x1 x2 x3 x4, _constr:(4)
| x1 x2 x3, _constr:(3)
| x1 x2, _constr:(2)
| x1, _constr:(1)
| _ ?T'get_term_existential_arity T'
| _let P := get_head T in
let T' := eval unfold P in T in
match T' with
| Tfail 1
| _get_term_existential_arity T'
end
end.

Ltac get_goal_existential_arity :=
match goal with ?Tget_term_existential_arity T end.

T1 ... TN is a shorthand for T1; ...; TN. It is intended to prove goals of the form exist X1 .. XN, P. If an argument provided is __ (double underscore), then an evar is introduced. T1 .. TN ___ is equivalent to T1 .. TN __ __ __ with as many __ as possible.

Tactic Notation "exists_original" constr(T1) :=
T1.
Tactic Notation "exists" constr(T1) :=
match T1 with
| ltac_wildesplit
| ltac_wildsrepeat esplit
| _T1
end.
Tactic Notation "exists" constr(T1) constr(T2) :=
T1; T2.
Tactic Notation "exists" constr(T1) constr(T2) constr(T3) :=
T1; T2; T3.
Tactic Notation "exists" constr(T1) constr(T2) constr(T3) constr(T4) :=
T1; T2; T3; T4.
Tactic Notation "exists" constr(T1) constr(T2) constr(T3) constr(T4)
constr(T5) :=
T1; T2; T3; T4; T5.
Tactic Notation "exists" constr(T1) constr(T2) constr(T3) constr(T4)
constr(T5) constr(T6) :=
T1; T2; T3; T4; T5; T6.

(* The tactic exists___ N is short for  __ ... __
with N double-underscores. The tactic  is equivalent
to calling exists___ N, where the value of N is obtained
by counting the number of existentials syntactically present
at the head of the goal. The behaviour of  differs
from that of  ___ is the case where the goal is a
definition which yields an existential only after unfolding. *)

Tactic Notation "exists___" constr(N) :=
let rec aux N :=
match N with
| 0 ⇒ idtac
| S ?N'esplit; aux N'
end in
let N := nat_from_number N in aux N.

(* todo: deprecated *)
Tactic Notation "exists___" :=
let N := get_goal_existential_arity in
exists___ N.

(* todo: does not seem to work *)
Tactic Notation "exists" :=
exists___.

(* todo: exists_all is the new syntax for exists___ *)
Tactic Notation "exists_all" := exists___.

(* ---------------------------------------------------------------------- *)
Existentials and conjunctions in hypotheses
unpack or unpack H destructs conjunctions and existentials in all or one hypothesis.

Ltac unpack_core :=
repeat match goal with
| H: _ _ _destruct H
| H: a, _ _destruct H
end.

Ltac unpack_from H :=
first [ progress (unpack_core)
| destruct H; unpack_core ].

Tactic Notation "unpack" :=
unpack_core.
Tactic Notation "unpack" constr(H) :=
unpack_from H.

(* ********************************************************************** *)

# Tactics to prove typeclass instances

typeclass is an automation tactic specialized for finding typeclass instances.

Tactic Notation "typeclass" :=
let go _ := eauto with typeclass_instances in
solve [ go tt | constructor; go tt ].

solve_typeclass is a simpler version of typeclass, to use in hint tactics for resolving instances

Tactic Notation "solve_typeclass" :=
solve [ eauto with typeclass_instances ].

(* ********************************************************************** *)

# Tactics to invoke automation

(* ---------------------------------------------------------------------- *)

## Definitions for parsing compatibility

Tactic Notation "f_equal" :=
f_equal.
Tactic Notation "constructor" :=
constructor.
Tactic Notation "simple" :=
simpl.

Tactic Notation "split" :=
split.

Tactic Notation "right" :=
right.
Tactic Notation "left" :=
left.

(* ---------------------------------------------------------------------- *)

## hint to add hints local to a lemma

hint E adds E as an hypothesis so that automation can use it. Syntax hint E1,..,EN is available

Tactic Notation "hint" constr(E) :=
let H := fresh "Hint" in lets H: E.
Tactic Notation "hint" constr(E1) "," constr(E2) :=
hint E1; hint E2.
Tactic Notation "hint" constr(E1) "," constr(E2) "," constr(E3) :=
hint E1; hint E2; hint(E3).
Tactic Notation "hint" constr(E1) "," constr(E2) "," constr(E3) "," constr(E4) :=
hint E1; hint E2; hint(E3); hint(E4 ).

(* ---------------------------------------------------------------------- *)

## jauto, a new automation tactics

jauto is better at intuition eauto because it can open existentials from the context. In the same time, jauto can be faster than intuition eauto because it does not destruct disjunctions from the context. The strategy of jauto can be summarized as follows:
• open all the existentials and conjunctions from the context
• call esplit and split on the existentials and conjunctions in the goal
• call eauto.

Tactic Notation "jauto" :=
try solve [ jauto_set; eauto ].

Tactic Notation "jauto_fast" :=
try solve [ auto | eauto | jauto ].

iauto is a shorthand for intuition eauto

Tactic Notation "iauto" := try solve [intuition eauto].

(* ---------------------------------------------------------------------- *)

## Definitions of automation tactics

The two following tactics defined the default behaviour of "light automation" and "strong automation". These tactics may be redefined at any time using the syntax Ltac .. ::= ...
auto_tilde is the tactic which will be called each time a symbol ¬ is used after a tactic.

Ltac auto_tilde_default := auto.
Ltac auto_tilde := auto_tilde_default.

auto_star is the tactic which will be called each time a symbol * is used after a tactic.

(* SPECIAL VERSION FOR SF*)
Ltac auto_star_default := try solve [ jauto ].
Ltac auto_star := auto_star_default.

autos¬ is a notation for tactic auto_tilde. It may be followed by lemmas (or proofs terms) which auto will be able to use for solving the goal. autos is an alias for autos¬

Tactic Notation "autos" :=
auto_tilde.
Tactic Notation "autos" "¬" :=
auto_tilde.
Tactic Notation "autos" "¬" constr(E1) :=
lets: E1; auto_tilde.
Tactic Notation "autos" "¬" constr(E1) constr(E2) :=
lets: E1; lets: E2; auto_tilde.
Tactic Notation "autos" "¬" constr(E1) constr(E2) constr(E3) :=
lets: E1; lets: E2; lets: E3; auto_tilde.

autos* is a notation for tactic auto_star. It may be followed by lemmas (or proofs terms) which auto will be able to use for solving the goal.

Tactic Notation "autos" "*" :=
auto_star.
Tactic Notation "autos" "*" constr(E1) :=
lets: E1; auto_star.
Tactic Notation "autos" "*" constr(E1) constr(E2) :=
lets: E1; lets: E2; auto_star.
Tactic Notation "autos" "*" constr(E1) constr(E2) constr(E3) :=
lets: E1; lets: E2; lets: E3; auto_star.

auto_false is a version of auto able to spot some contradictions. There is an ad-hoc support for goals in : split is called first. auto_false¬ and auto_false* are also available.

Ltac auto_false_base cont :=
try solve [
intros_all; try match goal with _ _split end;
solve [ cont tt | intros_all; false; cont tt ] ].

Tactic Notation "auto_false" :=
auto_false_base ltac:(fun ttauto).
Tactic Notation "auto_false" "¬" :=
auto_false_base ltac:(fun ttauto_tilde).
Tactic Notation "auto_false" "*" :=
auto_false_base ltac:(fun ttauto_star).

(* NOT NEEDED FOR SF (incompatible with V8.4)
Tactic Notation "dauto" :=
dintuition eauto.
*)

(* ---------------------------------------------------------------------- *)

## Parsing for light automation

Any tactic followed by the symbol ¬ will have auto_tilde called on all of its subgoals. Three exceptions:
• cuts and asserts only call auto on their first subgoal,
• apply¬ relies on sapply rather than apply,
• tryfalse¬ is defined as tryfalse by auto_tilde.
Some builtin tactics are not defined using tactic notations and thus cannot be extended, e.g., simpl and unfold. For these, notation such as simpl¬ will not be available.

Tactic Notation "equates" "¬" constr(E) :=
equates E; auto_tilde.
Tactic Notation "equates" "¬" constr(n1) constr(n2) :=
equates n1 n2; auto_tilde.
Tactic Notation "equates" "¬" constr(n1) constr(n2) constr(n3) :=
equates n1 n2 n3; auto_tilde.
Tactic Notation "equates" "¬" constr(n1) constr(n2) constr(n3) constr(n4) :=
equates n1 n2 n3 n4; auto_tilde.

Tactic Notation "applys_eq" "¬" constr(H) constr(E) :=
applys_eq H E; auto_tilde.
Tactic Notation "applys_eq" "¬" constr(H) constr(n1) constr(n2) :=
applys_eq H n1 n2; auto_tilde.
Tactic Notation "applys_eq" "¬" constr(H) constr(n1) constr(n2) constr(n3) :=
applys_eq H n1 n2 n3; auto_tilde.
Tactic Notation "applys_eq" "¬" constr(H) constr(n1) constr(n2) constr(n3) constr(n4) :=
applys_eq H n1 n2 n3 n4; auto_tilde.

Tactic Notation "apply" "¬" constr(H) :=
sapply H; auto_tilde.

Tactic Notation "destruct" "¬" constr(H) :=
destruct H; auto_tilde.
Tactic Notation "destruct" "¬" constr(H) "as" simple_intropattern(I) :=
destruct H as I; auto_tilde.
Tactic Notation "f_equal" "¬" :=
f_equal; auto_tilde.
Tactic Notation "induction" "¬" constr(H) :=
induction H; auto_tilde.
Tactic Notation "inversion" "¬" constr(H) :=
inversion H; auto_tilde.
Tactic Notation "split" "¬" :=
split; auto_tilde.
Tactic Notation "subst" "¬" :=
subst; auto_tilde.
Tactic Notation "right" "¬" :=
right; auto_tilde.
Tactic Notation "left" "¬" :=
left; auto_tilde.
Tactic Notation "constructor" "¬" :=
constructor; auto_tilde.
Tactic Notation "constructors" "¬" :=
constructors; auto_tilde.

Tactic Notation "false" "¬" :=
false; auto_tilde.
Tactic Notation "false" "¬" constr(E) :=
false_then E ltac:(fun _auto_tilde).
Tactic Notation "false" "¬" constr(E0) constr(E1) :=
false¬ (>> E0 E1).
Tactic Notation "false" "¬" constr(E0) constr(E1) constr(E2) :=
false¬ (>> E0 E1 E2).
Tactic Notation "false" "¬" constr(E0) constr(E1) constr(E2) constr(E3) :=
false¬ (>> E0 E1 E2 E3).
Tactic Notation "false" "¬" constr(E0) constr(E1) constr(E2) constr(E3) constr(E4) :=
false¬ (>> E0 E1 E2 E3 E4).
Tactic Notation "tryfalse" "¬" :=
try solve [ false¬ ].

Tactic Notation "asserts" "¬" simple_intropattern(H) ":" constr(E) :=
asserts H: E; [ auto_tilde | idtac ].
Tactic Notation "asserts" "¬" ":" constr(E) :=
let H := fresh "H" in asserts¬ H: E.
Tactic Notation "cuts" "¬" simple_intropattern(H) ":" constr(E) :=
cuts H: E; [ auto_tilde | idtac ].
Tactic Notation "cuts" "¬" ":" constr(E) :=
cuts: E; [ auto_tilde | idtac ].

Tactic Notation "lets" "¬" simple_intropattern(I) ":" constr(E) :=
lets I: E; auto_tilde.
Tactic Notation "lets" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) :=
lets I: E0 A1; auto_tilde.
Tactic Notation "lets" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) :=
lets I: E0 A1 A2; auto_tilde.
Tactic Notation "lets" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
lets I: E0 A1 A2 A3; auto_tilde.
Tactic Notation "lets" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
lets I: E0 A1 A2 A3 A4; auto_tilde.
Tactic Notation "lets" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
lets I: E0 A1 A2 A3 A4 A5; auto_tilde.

Tactic Notation "lets" "¬" ":" constr(E) :=
lets: E; auto_tilde.
Tactic Notation "lets" "¬" ":" constr(E0)
constr(A1) :=
lets: E0 A1; auto_tilde.
Tactic Notation "lets" "¬" ":" constr(E0)
constr(A1) constr(A2) :=
lets: E0 A1 A2; auto_tilde.
Tactic Notation "lets" "¬" ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
lets: E0 A1 A2 A3; auto_tilde.
Tactic Notation "lets" "¬" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
lets: E0 A1 A2 A3 A4; auto_tilde.
Tactic Notation "lets" "¬" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
lets: E0 A1 A2 A3 A4 A5; auto_tilde.

Tactic Notation "forwards" "¬" simple_intropattern(I) ":" constr(E) :=
forwards I: E; auto_tilde.
Tactic Notation "forwards" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) :=
forwards I: E0 A1; auto_tilde.
Tactic Notation "forwards" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) :=
forwards I: E0 A1 A2; auto_tilde.
Tactic Notation "forwards" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
forwards I: E0 A1 A2 A3; auto_tilde.
Tactic Notation "forwards" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
forwards I: E0 A1 A2 A3 A4; auto_tilde.
Tactic Notation "forwards" "¬" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
forwards I: E0 A1 A2 A3 A4 A5; auto_tilde.

Tactic Notation "forwards" "¬" ":" constr(E) :=
forwards: E; auto_tilde.
Tactic Notation "forwards" "¬" ":" constr(E0)
constr(A1) :=
forwards: E0 A1; auto_tilde.
Tactic Notation "forwards" "¬" ":" constr(E0)
constr(A1) constr(A2) :=
forwards: E0 A1 A2; auto_tilde.
Tactic Notation "forwards" "¬" ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
forwards: E0 A1 A2 A3; auto_tilde.
Tactic Notation "forwards" "¬" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
forwards: E0 A1 A2 A3 A4; auto_tilde.
Tactic Notation "forwards" "¬" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
forwards: E0 A1 A2 A3 A4 A5; auto_tilde.

Tactic Notation "applys" "¬" constr(H) :=
sapply H; auto_tilde. (*todo?*)
Tactic Notation "applys" "¬" constr(E0) constr(A1) :=
applys E0 A1; auto_tilde.
Tactic Notation "applys" "¬" constr(E0) constr(A1) :=
applys E0 A1; auto_tilde.
Tactic Notation "applys" "¬" constr(E0) constr(A1) constr(A2) :=
applys E0 A1 A2; auto_tilde.
Tactic Notation "applys" "¬" constr(E0) constr(A1) constr(A2) constr(A3) :=
applys E0 A1 A2 A3; auto_tilde.
Tactic Notation "applys" "¬" constr(E0) constr(A1) constr(A2) constr(A3) constr(A4) :=
applys E0 A1 A2 A3 A4; auto_tilde.
Tactic Notation "applys" "¬" constr(E0) constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
applys E0 A1 A2 A3 A4 A5; auto_tilde.

Tactic Notation "specializes" "¬" hyp(H) :=
specializes H; auto_tilde.
Tactic Notation "specializes" "¬" hyp(H) constr(A1) :=
specializes H A1; auto_tilde.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) :=
specializes H A1 A2; auto_tilde.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) :=
specializes H A1 A2 A3; auto_tilde.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) constr(A4) :=
specializes H A1 A2 A3 A4; auto_tilde.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
specializes H A1 A2 A3 A4 A5; auto_tilde.

Tactic Notation "fapply" "¬" constr(E) :=
fapply E; auto_tilde.
Tactic Notation "sapply" "¬" constr(E) :=
sapply E; auto_tilde.

Tactic Notation "logic" "¬" constr(E) :=
logic_base E ltac:(fun _auto_tilde).

Tactic Notation "intros_all" "¬" :=
intros_all; auto_tilde.

Tactic Notation "unfolds" "¬" :=
unfolds; auto_tilde.
Tactic Notation "unfolds" "¬" constr(F1) :=
unfolds F1; auto_tilde.
Tactic Notation "unfolds" "¬" constr(F1) "," constr(F2) :=
unfolds F1, F2; auto_tilde.
Tactic Notation "unfolds" "¬" constr(F1) "," constr(F2) "," constr(F3) :=
unfolds F1, F2, F3; auto_tilde.
Tactic Notation "unfolds" "¬" constr(F1) "," constr(F2) "," constr(F3) ","
constr(F4) :=
unfolds F1, F2, F3, F4; auto_tilde.

Tactic Notation "simple" "¬" :=
simpl; auto_tilde.
Tactic Notation "simple" "¬" "in" hyp(H) :=
simpl in H; auto_tilde.
Tactic Notation "simpls" "¬" :=
simpls; auto_tilde.
Tactic Notation "hnfs" "¬" :=
hnfs; auto_tilde.
Tactic Notation "hnfs" "¬" "in" hyp(H) :=
hnf in H; auto_tilde.
Tactic Notation "substs" "¬" :=
substs; auto_tilde.
Tactic Notation "intro_hyp" "¬" hyp(H) :=
subst_hyp H; auto_tilde.
Tactic Notation "intro_subst" "¬" :=
intro_subst; auto_tilde.
Tactic Notation "subst_eq" "¬" constr(E) :=
subst_eq E; auto_tilde.

Tactic Notation "rewrite" "¬" constr(E) :=
rewrite E; auto_tilde.
Tactic Notation "rewrite" "¬" "" constr(E) :=
rewrite E; auto_tilde.
Tactic Notation "rewrite" "¬" constr(E) "in" hyp(H) :=
rewrite E in H; auto_tilde.
Tactic Notation "rewrite" "¬" "" constr(E) "in" hyp(H) :=
rewrite E in H; auto_tilde.

Tactic Notation "rewrites" "¬" constr(E) :=
rewrites E; auto_tilde.
Tactic Notation "rewrites" "¬" constr(E) "in" hyp(H) :=
rewrites E in H; auto_tilde.
Tactic Notation "rewrites" "¬" constr(E) "in" "*" :=
rewrites E in *; auto_tilde.
Tactic Notation "rewrites" "¬" "" constr(E) :=
rewrites E; auto_tilde.
Tactic Notation "rewrites" "¬" "" constr(E) "in" hyp(H) :=
rewrites E in H; auto_tilde.
Tactic Notation "rewrites" "¬" "" constr(E) "in" "*" :=
rewrites E in *; auto_tilde.

Tactic Notation "rewrite_all" "¬" constr(E) :=
rewrite_all E; auto_tilde.
Tactic Notation "rewrite_all" "¬" "" constr(E) :=
rewrite_all E; auto_tilde.
Tactic Notation "rewrite_all" "¬" constr(E) "in" ident(H) :=
rewrite_all E in H; auto_tilde.
Tactic Notation "rewrite_all" "¬" "" constr(E) "in" ident(H) :=
rewrite_all E in H; auto_tilde.
Tactic Notation "rewrite_all" "¬" constr(E) "in" "*" :=
rewrite_all E in *; auto_tilde.
Tactic Notation "rewrite_all" "¬" "" constr(E) "in" "*" :=
rewrite_all E in *; auto_tilde.

Tactic Notation "asserts_rewrite" "¬" constr(E) :=
asserts_rewrite E; auto_tilde.
Tactic Notation "asserts_rewrite" "¬" "" constr(E) :=
asserts_rewrite E; auto_tilde.
Tactic Notation "asserts_rewrite" "¬" constr(E) "in" hyp(H) :=
asserts_rewrite E in H; auto_tilde.
Tactic Notation "asserts_rewrite" "¬" "" constr(E) "in" hyp(H) :=
asserts_rewrite E in H; auto_tilde.
Tactic Notation "asserts_rewrite" "¬" constr(E) "in" "*" :=
asserts_rewrite E in *; auto_tilde.
Tactic Notation "asserts_rewrite" "¬" "" constr(E) "in" "*" :=
asserts_rewrite E in *; auto_tilde.

Tactic Notation "cuts_rewrite" "¬" constr(E) :=
cuts_rewrite E; auto_tilde.
Tactic Notation "cuts_rewrite" "¬" "" constr(E) :=
cuts_rewrite E; auto_tilde.
Tactic Notation "cuts_rewrite" "¬" constr(E) "in" hyp(H) :=
cuts_rewrite E in H; auto_tilde.
Tactic Notation "cuts_rewrite" "¬" "" constr(E) "in" hyp(H) :=
cuts_rewrite E in H; auto_tilde.

Tactic Notation "erewrite" "¬" constr(E) :=
erewrite E; auto_tilde.

Tactic Notation "fequal" "¬" :=
fequal; auto_tilde.
Tactic Notation "fequals" "¬" :=
fequals; auto_tilde.
Tactic Notation "pi_rewrite" "¬" constr(E) :=
pi_rewrite E; auto_tilde.
Tactic Notation "pi_rewrite" "¬" constr(E) "in" hyp(H) :=
pi_rewrite E in H; auto_tilde.

Tactic Notation "invert" "¬" hyp(H) :=
invert H; auto_tilde.
Tactic Notation "inverts" "¬" hyp(H) :=
inverts H; auto_tilde.
Tactic Notation "inverts" "¬" hyp(E) "as" :=
inverts E as; auto_tilde.
Tactic Notation "injects" "¬" hyp(H) :=
injects H; auto_tilde.
Tactic Notation "inversions" "¬" hyp(H) :=
inversions H; auto_tilde.

Tactic Notation "cases" "¬" constr(E) "as" ident(H) :=
cases E as H; auto_tilde.
Tactic Notation "cases" "¬" constr(E) :=
cases E; auto_tilde.
Tactic Notation "case_if" "¬" :=
case_if; auto_tilde.
Tactic Notation "case_ifs" "¬" :=
case_ifs; auto_tilde.
Tactic Notation "case_if" "¬" "in" hyp(H) :=
case_if in H; auto_tilde.
Tactic Notation "cases_if" "¬" :=
cases_if; auto_tilde.
Tactic Notation "cases_if" "¬" "in" hyp(H) :=
cases_if in H; auto_tilde.
Tactic Notation "destruct_if" "¬" :=
destruct_if; auto_tilde.
Tactic Notation "destruct_if" "¬" "in" hyp(H) :=
destruct_if in H; auto_tilde.
Tactic Notation "destruct_head_match" "¬" :=

Tactic Notation "cases'" "¬" constr(E) "as" ident(H) :=
cases' E as H; auto_tilde.
Tactic Notation "cases'" "¬" constr(E) :=
cases' E; auto_tilde.
Tactic Notation "cases_if'" "¬" "as" ident(H) :=
cases_if' as H; auto_tilde.
Tactic Notation "cases_if'" "¬" :=
cases_if'; auto_tilde.

Tactic Notation "decides_equality" "¬" :=
decides_equality; auto_tilde.

Tactic Notation "iff" "¬" :=
iff; auto_tilde.
Tactic Notation "splits" "¬" :=
splits; auto_tilde.
Tactic Notation "splits" "¬" constr(N) :=
splits N; auto_tilde.
Tactic Notation "splits_all" "¬" :=
splits_all; auto_tilde.

Tactic Notation "destructs" "¬" constr(T) :=
destructs T; auto_tilde.
Tactic Notation "destructs" "¬" constr(N) constr(T) :=
destructs N T; auto_tilde.

Tactic Notation "branch" "¬" constr(N) :=
branch N; auto_tilde.
Tactic Notation "branch" "¬" constr(K) "of" constr(N) :=
branch K of N; auto_tilde.

Tactic Notation "branches" "¬" constr(T) :=
branches T; auto_tilde.
Tactic Notation "branches" "¬" constr(N) constr(T) :=
branches N T; auto_tilde.

Tactic Notation "exists" "¬" :=
; auto_tilde.
Tactic Notation "exists___" "¬" :=
exists___; auto_tilde.
Tactic Notation "exists" "¬" constr(T1) :=
T1; auto_tilde.
Tactic Notation "exists" "¬" constr(T1) constr(T2) :=
T1 T2; auto_tilde.
Tactic Notation "exists" "¬" constr(T1) constr(T2) constr(T3) :=
T1 T2 T3; auto_tilde.
Tactic Notation "exists" "¬" constr(T1) constr(T2) constr(T3) constr(T4) :=
T1 T2 T3 T4; auto_tilde.
Tactic Notation "exists" "¬" constr(T1) constr(T2) constr(T3) constr(T4)
constr(T5) :=
T1 T2 T3 T4 T5; auto_tilde.
Tactic Notation "exists" "¬" constr(T1) constr(T2) constr(T3) constr(T4)
constr(T5) constr(T6) :=
T1 T2 T3 T4 T5 T6; auto_tilde.

(* ---------------------------------------------------------------------- *)

## Parsing for strong automation

Any tactic followed by the symbol * will have auto* called on all of its subgoals. The exceptions to these rules are the same as for light automation.
Exception: use subs* instead of subst* if you import the library Coq.Classes.Equivalence.

Tactic Notation "equates" "*" constr(E) :=
equates E; auto_star.
Tactic Notation "equates" "*" constr(n1) constr(n2) :=
equates n1 n2; auto_star.
Tactic Notation "equates" "*" constr(n1) constr(n2) constr(n3) :=
equates n1 n2 n3; auto_star.
Tactic Notation "equates" "*" constr(n1) constr(n2) constr(n3) constr(n4) :=
equates n1 n2 n3 n4; auto_star.

Tactic Notation "applys_eq" "*" constr(H) constr(E) :=
applys_eq H E; auto_star.
Tactic Notation "applys_eq" "*" constr(H) constr(n1) constr(n2) :=
applys_eq H n1 n2; auto_star.
Tactic Notation "applys_eq" "*" constr(H) constr(n1) constr(n2) constr(n3) :=
applys_eq H n1 n2 n3; auto_star.
Tactic Notation "applys_eq" "*" constr(H) constr(n1) constr(n2) constr(n3) constr(n4) :=
applys_eq H n1 n2 n3 n4; auto_star.

Tactic Notation "apply" "*" constr(H) :=
sapply H; auto_star.

Tactic Notation "destruct" "*" constr(H) :=
destruct H; auto_star.
Tactic Notation "destruct" "*" constr(H) "as" simple_intropattern(I) :=
destruct H as I; auto_star.
Tactic Notation "f_equal" "*" :=
f_equal; auto_star.
Tactic Notation "induction" "*" constr(H) :=
induction H; auto_star.
Tactic Notation "inversion" "*" constr(H) :=
inversion H; auto_star.
Tactic Notation "split" "*" :=
split; auto_star.
Tactic Notation "subs" "*" :=
subst; auto_star.
Tactic Notation "subst" "*" :=
subst; auto_star.
Tactic Notation "right" "*" :=
right; auto_star.
Tactic Notation "left" "*" :=
left; auto_star.
Tactic Notation "constructor" "*" :=
constructor; auto_star.
Tactic Notation "constructors" "*" :=
constructors; auto_star.

Tactic Notation "false" "*" :=
false; auto_star.
Tactic Notation "false" "*" constr(E) :=
false_then E ltac:(fun _auto_star).
Tactic Notation "false" "*" constr(E0) constr(E1) :=
false* (>> E0 E1).
Tactic Notation "false" "*" constr(E0) constr(E1) constr(E2) :=
false* (>> E0 E1 E2).
Tactic Notation "false" "*" constr(E0) constr(E1) constr(E2) constr(E3) :=
false* (>> E0 E1 E2 E3).
Tactic Notation "false" "*" constr(E0) constr(E1) constr(E2) constr(E3) constr(E4) :=
false* (>> E0 E1 E2 E3 E4).
Tactic Notation "tryfalse" "*" :=
try solve [ false* ].

Tactic Notation "asserts" "*" simple_intropattern(H) ":" constr(E) :=
asserts H: E; [ auto_star | idtac ].
Tactic Notation "asserts" "*" ":" constr(E) :=
let H := fresh "H" in asserts* H: E.
Tactic Notation "cuts" "*" simple_intropattern(H) ":" constr(E) :=
cuts H: E; [ auto_star | idtac ].
Tactic Notation "cuts" "*" ":" constr(E) :=
cuts: E; [ auto_star | idtac ].

Tactic Notation "lets" "*" simple_intropattern(I) ":" constr(E) :=
lets I: E; auto_star.
Tactic Notation "lets" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) :=
lets I: E0 A1; auto_star.
Tactic Notation "lets" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) :=
lets I: E0 A1 A2; auto_star.
Tactic Notation "lets" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
lets I: E0 A1 A2 A3; auto_star.
Tactic Notation "lets" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
lets I: E0 A1 A2 A3 A4; auto_star.
Tactic Notation "lets" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
lets I: E0 A1 A2 A3 A4 A5; auto_star.

Tactic Notation "lets" "*" ":" constr(E) :=
lets: E; auto_star.
Tactic Notation "lets" "*" ":" constr(E0)
constr(A1) :=
lets: E0 A1; auto_star.
Tactic Notation "lets" "*" ":" constr(E0)
constr(A1) constr(A2) :=
lets: E0 A1 A2; auto_star.
Tactic Notation "lets" "*" ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
lets: E0 A1 A2 A3; auto_star.
Tactic Notation "lets" "*" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
lets: E0 A1 A2 A3 A4; auto_star.
Tactic Notation "lets" "*" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
lets: E0 A1 A2 A3 A4 A5; auto_star.

Tactic Notation "forwards" "*" simple_intropattern(I) ":" constr(E) :=
forwards I: E; auto_star.
Tactic Notation "forwards" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) :=
forwards I: E0 A1; auto_star.
Tactic Notation "forwards" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) :=
forwards I: E0 A1 A2; auto_star.
Tactic Notation "forwards" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
forwards I: E0 A1 A2 A3; auto_star.
Tactic Notation "forwards" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
forwards I: E0 A1 A2 A3 A4; auto_star.
Tactic Notation "forwards" "*" simple_intropattern(I) ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
forwards I: E0 A1 A2 A3 A4 A5; auto_star.

Tactic Notation "forwards" "*" ":" constr(E) :=
forwards: E; auto_star.
Tactic Notation "forwards" "*" ":" constr(E0)
constr(A1) :=
forwards: E0 A1; auto_star.
Tactic Notation "forwards" "*" ":" constr(E0)
constr(A1) constr(A2) :=
forwards: E0 A1 A2; auto_star.
Tactic Notation "forwards" "*" ":" constr(E0)
constr(A1) constr(A2) constr(A3) :=
forwards: E0 A1 A2 A3; auto_star.
Tactic Notation "forwards" "*" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) :=
forwards: E0 A1 A2 A3 A4; auto_star.
Tactic Notation "forwards" "*" ":" constr(E0)
constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
forwards: E0 A1 A2 A3 A4 A5; auto_star.

Tactic Notation "applys" "*" constr(H) :=
sapply H; auto_star. (*todo?*)
Tactic Notation "applys" "*" constr(E0) constr(A1) :=
applys E0 A1; auto_star.
Tactic Notation "applys" "*" constr(E0) constr(A1) :=
applys E0 A1; auto_star.
Tactic Notation "applys" "*" constr(E0) constr(A1) constr(A2) :=
applys E0 A1 A2; auto_star.
Tactic Notation "applys" "*" constr(E0) constr(A1) constr(A2) constr(A3) :=
applys E0 A1 A2 A3; auto_star.
Tactic Notation "applys" "*" constr(E0) constr(A1) constr(A2) constr(A3) constr(A4) :=
applys E0 A1 A2 A3 A4; auto_star.
Tactic Notation "applys" "*" constr(E0) constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
applys E0 A1 A2 A3 A4 A5; auto_star.

Tactic Notation "specializes" "*" hyp(H) :=
specializes H; auto_star.
Tactic Notation "specializes" "¬" hyp(H) constr(A1) :=
specializes H A1; auto_star.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) :=
specializes H A1 A2; auto_star.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) :=
specializes H A1 A2 A3; auto_star.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) constr(A4) :=
specializes H A1 A2 A3 A4; auto_star.
Tactic Notation "specializes" hyp(H) constr(A1) constr(A2) constr(A3) constr(A4) constr(A5) :=
specializes H A1 A2 A3 A4 A5; auto_star.

Tactic Notation "fapply" "*" constr(E) :=
fapply E; auto_star.
Tactic Notation "sapply" "*" constr(E) :=
sapply E; auto_star.

Tactic Notation "logic" constr(E) :=
logic_base E ltac:(fun _auto_star).

Tactic Notation "intros_all" "*" :=
intros_all; auto_star.

Tactic Notation "unfolds" "*" :=
unfolds; auto_star.
Tactic Notation "unfolds" "*" constr(F1) :=
unfolds F1; auto_star.
Tactic Notation "unfolds" "*" constr(F1) "," constr(F2) :=
unfolds F1, F2; auto_star.
Tactic Notation "unfolds" "*" constr(F1) "," constr(F2) "," constr(F3) :=
unfolds F1, F2, F3; auto_star.
Tactic Notation "unfolds" "*" constr(F1) "," constr(F2) "," constr(F3) ","
constr(F4) :=
unfolds F1, F2, F3, F4; auto_star.

Tactic Notation "simple" "*" :=
simpl; auto_star.
Tactic Notation "simple" "*" "in" hyp(H) :=
simpl in H; auto_star.
Tactic Notation "simpls" "*" :=
simpls; auto_star.
Tactic Notation "hnfs" "*" :=
hnfs; auto_star.
Tactic Notation "hnfs" "*" "in" hyp(H) :=
hnf in H; auto_star.
Tactic Notation "substs" "*" :=
substs; auto_star.
Tactic Notation "intro_hyp" "*" hyp(H) :=
subst_hyp H; auto_star.
Tactic Notation "intro_subst" "*" :=
intro_subst; auto_star.
Tactic Notation "subst_eq" "*" constr(E) :=
subst_eq E; auto_star.

Tactic Notation "rewrite" "*" constr(E) :=
rewrite E; auto_star.
Tactic Notation "rewrite" "*" "" constr(E) :=
rewrite E; auto_star.
Tactic Notation "rewrite" "*" constr(E) "in" hyp(H) :=
rewrite E in H; auto_star.
Tactic Notation "rewrite" "*" "" constr(E) "in" hyp(H) :=
rewrite E in H; auto_star.

Tactic Notation "rewrites" "*" constr(E) :=
rewrites E; auto_star.
Tactic Notation "rewrites" "*" constr(E) "in" hyp(H):=
rewrites E in H; auto_star.
Tactic Notation "rewrites" "*" constr(E) "in" "*":=
rewrites E in *; auto_star.
Tactic Notation "rewrites" "*" "" constr(E) :=
rewrites E; auto_star.
Tactic Notation "rewrites" "*" "" constr(E) "in" hyp(H):=
rewrites E in H; auto_star.
Tactic Notation "rewrites" "*" "" constr(E) "in" "*":=
rewrites E in *; auto_star.

Tactic Notation "rewrite_all" "*" constr(E) :=
rewrite_all E; auto_star.
Tactic Notation "rewrite_all" "*" "" constr(E) :=
rewrite_all E; auto_star.
Tactic Notation "rewrite_all" "*" constr(E) "in" ident(H) :=
rewrite_all E in H; auto_star.
Tactic Notation "rewrite_all" "*" "" constr(E) "in" ident(H) :=
rewrite_all E in H; auto_star.
Tactic Notation "rewrite_all" "*" constr(E) "in" "*" :=
rewrite_all E in *; auto_star.
Tactic Notation "rewrite_all" "*" "" constr(E) "in" "*" :=
rewrite_all E in *; auto_star.

Tactic Notation "asserts_rewrite" "*" constr(E) :=
asserts_rewrite E; auto_star.
Tactic Notation "asserts_rewrite" "*" "" constr(E) :=
asserts_rewrite E; auto_star.
Tactic Notation "asserts_rewrite" "*" constr(E) "in" hyp(H) :=
asserts_rewrite E; auto_star.
Tactic Notation "asserts_rewrite" "*" "" constr(E) "in" hyp(H) :=
asserts_rewrite E; auto_star.
Tactic Notation "asserts_rewrite" "*" constr(E) "in" "*" :=
asserts_rewrite E in *; auto_tilde.
Tactic Notation "asserts_rewrite" "*" "" constr(E) "in" "*" :=
asserts_rewrite E in *; auto_tilde.

Tactic Notation "cuts_rewrite" "*" constr(E) :=
cuts_rewrite E; auto_star.
Tactic Notation "cuts_rewrite" "*" "" constr(E) :=
cuts_rewrite E; auto_star.
Tactic Notation "cuts_rewrite" "*" constr(E) "in" hyp(H) :=
cuts_rewrite E in H; auto_star.
Tactic Notation "cuts_rewrite" "*" "" constr(E) "in" hyp(H) :=
cuts_rewrite E in H; auto_star.

Tactic Notation "erewrite" "*" constr(E) :=
erewrite E; auto_star.

Tactic Notation "fequal" "*" :=
fequal; auto_star.
Tactic Notation "fequals" "*" :=
fequals; auto_star.
Tactic Notation "pi_rewrite" "*" constr(E) :=
pi_rewrite E; auto_star.
Tactic Notation "pi_rewrite" "*" constr(E) "in" hyp(H) :=
pi_rewrite E in H; auto_star.

Tactic Notation "invert" "*" hyp(H) :=
invert H; auto_star.
Tactic Notation "inverts" "*" hyp(H) :=
inverts H; auto_star.
Tactic Notation "inverts" "*" hyp(E) "as" :=
inverts E as; auto_star.
Tactic Notation "injects" "*" hyp(H) :=
injects H; auto_star.
Tactic Notation "inversions" "*" hyp(H) :=
inversions H; auto_star.

Tactic Notation "cases" "*" constr(E) "as" ident(H) :=
cases E as H; auto_star.
Tactic Notation "cases" "*" constr(E) :=
cases E; auto_star.
Tactic Notation "case_if" "*" :=
case_if; auto_star.
Tactic Notation "case_ifs" "*" :=
case_ifs; auto_star.
Tactic Notation "case_if" "*" "in" hyp(H) :=
case_if in H; auto_star.
Tactic Notation "cases_if" "*" :=
cases_if; auto_star.
Tactic Notation "cases_if" "*" "in" hyp(H) :=
cases_if in H; auto_star.
Tactic Notation "destruct_if" "*" :=
destruct_if; auto_star.
Tactic Notation "destruct_if" "*" "in" hyp(H) :=
destruct_if in H; auto_star.
Tactic Notation "destruct_head_match" "*" :=

Tactic Notation "cases'" "*" constr(E) "as" ident(H) :=
cases' E as H; auto_star.
Tactic Notation "cases'" "*" constr(E) :=
cases' E; auto_star.
Tactic Notation "cases_if'" "*" "as" ident(H) :=
cases_if' as H; auto_star.
Tactic Notation "cases_if'" "*" :=
cases_if'; auto_star.

Tactic Notation "decides_equality" "*" :=
decides_equality; auto_star.

Tactic Notation "iff" "*" :=
iff; auto_star.
Tactic Notation "iff" "*" simple_intropattern(I) :=
iff I; auto_star.
Tactic Notation "splits" "*" :=
splits; auto_star.
Tactic Notation "splits" "*" constr(N) :=
splits N; auto_star.
Tactic Notation "splits_all" "*" :=
splits_all; auto_star.

Tactic Notation "destructs" "*" constr(T) :=
destructs T; auto_star.
Tactic Notation "destructs" "*" constr(N) constr(T) :=
destructs N T; auto_star.

Tactic Notation "branch" "*" constr(N) :=
branch N; auto_star.
Tactic Notation "branch" "*" constr(K) "of" constr(N) :=
branch K of N; auto_star.

Tactic Notation "branches" "*" constr(T) :=
branches T; auto_star.
Tactic Notation "branches" "*" constr(N) constr(T) :=
branches N T; auto_star.

Tactic Notation "exists" "*" :=
; auto_star.
Tactic Notation "exists___" "*" :=
exists___; auto_star.
Tactic Notation "exists" "*" constr(T1) :=
T1; auto_star.
Tactic Notation "exists" "*" constr(T1) constr(T2) :=
T1 T2; auto_star.
Tactic Notation "exists" "*" constr(T1) constr(T2) constr(T3) :=
T1 T2 T3; auto_star.
Tactic Notation "exists" "*" constr(T1) constr(T2) constr(T3) constr(T4) :=
T1 T2 T3 T4; auto_star.
Tactic Notation "exists" "*" constr(T1) constr(T2) constr(T3) constr(T4)
constr(T5) :=
T1 T2 T3 T4 T5; auto_star.
Tactic Notation "exists" "*" constr(T1) constr(T2) constr(T3) constr(T4)
constr(T5) constr(T6) :=
T1 T2 T3 T4 T5 T6; auto_star.

(* ********************************************************************** *)

# Tactics to sort out the proof context

(* ---------------------------------------------------------------------- *)

## Hiding hypotheses

(* Implementation *)

Definition ltac_something (P:Type) (e:P) := e.

Notation "'Something'" :=
(@ltac_something _ _).

Lemma ltac_something_eq : (e:Type),
e = (@ltac_something _ e).
Proof using. auto. Qed.

Lemma ltac_something_hide : (e:Type),
e (@ltac_something _ e).
Proof using. auto. Qed.

Lemma ltac_something_show : (e:Type),
(@ltac_something _ e) e.
Proof using. auto. Qed.

hide_def x and show_def x can be used to hide/show the body of the definition x.

Tactic Notation "hide_def" hyp(x) :=
let x' := constr:(x) in
let T := eval unfold x in x' in
change T with (@ltac_something _ T) in x.

Tactic Notation "show_def" hyp(x) :=
let x' := constr:(x) in
let U := eval unfold x in x' in
match U with @ltac_something _ ?T
change U with T in x end.

show_def unfolds Something in the goal

Tactic Notation "show_def" :=
unfold ltac_something.
Tactic Notation "show_def" "in" hyp(H) :=
unfold ltac_something in H.
Tactic Notation "show_def" "in" "*" :=
unfold ltac_something in *.

hide_defs and show_defs applies to all definitions

Tactic Notation "hide_defs" :=
repeat match goal with H := ?T _
match T with
| @ltac_something _ _fail 1
| _change T with (@ltac_something _ T) in H
end
end.

Tactic Notation "show_defs" :=
repeat match goal with H := (@ltac_something _ ?T) _
change (@ltac_something _ T) with T in H end.

hide_hyp H replaces the type of H with the notation Something and show_hyp H reveals the type of the hypothesis. Note that the hidden type of H remains convertible the real type of H.

Tactic Notation "show_hyp" hyp(H) :=
apply ltac_something_show in H.

Tactic Notation "hide_hyp" hyp(H) :=
apply ltac_something_hide in H.

hide_hyps and show_hyps can be used to hide/show all hypotheses of type Prop.

Tactic Notation "show_hyps" :=
repeat match goal with
H: @ltac_something _ _ _show_hyp H end.

Tactic Notation "hide_hyps" :=
repeat match goal with H: ?T _
match type of T with
| Prop
match T with
| @ltac_something _ _fail 2
| _hide_hyp H
end
| _fail 1
end
end.

hide H and show H automatically select between hide_hyp or hide_def, and show_hyp or show_def. Similarly hide_all and show_all apply to all.

Tactic Notation "hide" hyp(H) :=
first [hide_def H | hide_hyp H].

Tactic Notation "show" hyp(H) :=
first [show_def H | show_hyp H].

Tactic Notation "hide_all" :=
hide_hyps; hide_defs.

Tactic Notation "show_all" :=
unfold ltac_something in *.

hide_term E can be used to hide a term from the goal. show_term or show_term E can be used to reveal it. hide_term E in H can be used to specify an hypothesis.

Tactic Notation "hide_term" constr(E) :=
change E with (@ltac_something _ E).
Tactic Notation "show_term" constr(E) :=
change (@ltac_something _ E) with E.
Tactic Notation "show_term" :=
unfold ltac_something.

Tactic Notation "hide_term" constr(E) "in" hyp(H) :=
change E with (@ltac_something _ E) in H.
Tactic Notation "show_term" constr(E) "in" hyp(H) :=
change (@ltac_something _ E) with E in H.
Tactic Notation "show_term" "in" hyp(H) :=
unfold ltac_something in H.

show_unfold R unfolds the definition of R and reveals the hidden definition of R. —todo:test, and implement using unfold simply
(* todo: change "unfolds" *)

Tactic Notation "show_unfold" constr(R1) :=
unfold R1; show_def.
Tactic Notation "show_unfold" constr(R1) "," constr(R2) :=
unfold R1, R2; show_def.

(* ---------------------------------------------------------------------- *)

## Sorting hypotheses

sort sorts out hypotheses from the context by moving all the propositions (hypotheses of type Prop) to the bottom of the context.

Ltac sort_tactic :=
try match goal with H: ?T _
match type of T with Prop
generalizes H; (try sort_tactic); intro
end end.

Tactic Notation "sort" :=
sort_tactic.

(* ---------------------------------------------------------------------- *)

## Clearing hypotheses

clears X1 ... XN is a variation on clear which clears the variables X1..XN as well as all the hypotheses which depend on them. Contrary to clear, it never fails.

Tactic Notation "clears" ident(X1) :=
let rec doit _ :=
match goal with
| H:context[X1] _clear H; try (doit tt)
| _clear X1
end in doit tt.
Tactic Notation "clears" ident(X1) ident(X2) :=
clears X1; clears X2.
Tactic Notation "clears" ident(X1) ident(X2) ident(X3) :=
clears X1; clears X2; clears X3.
Tactic Notation "clears" ident(X1) ident(X2) ident(X3) ident(X4) :=
clears X1; clears X2; clears X3; clears X4.
Tactic Notation "clears" ident(X1) ident(X2) ident(X3) ident(X4)
ident(X5) :=
clears X1; clears X2; clears X3; clears X4; clears X5.
Tactic Notation "clears" ident(X1) ident(X2) ident(X3) ident(X4)
ident(X5) ident(X6) :=
clears X1; clears X2; clears X3; clears X4; clears X5; clears X6.

clears (without any argument) clears all the unused variables from the context. In other words, it removes any variable which is not a proposition (i.e., not of type Prop) and which does not appear in another hypothesis nor in the goal.
(* todo: rename to clears_var ? *)

Ltac clears_tactic :=
match goal with H: ?T _
match type of T with
| Propgeneralizes H; (try clears_tactic); intro
| ?TTclear H; (try clears_tactic)
| ?TTgeneralizes H; (try clears_tactic); intro
end end.

Tactic Notation "clears" :=
clears_tactic.

clears_all clears all the hypotheses from the context that can be cleared. It leaves only the hypotheses that are mentioned in the goal.

Ltac clears_or_generalizes_all_core :=
repeat match goal with H: _ _
first [ clear H | generalizes H] end.

Tactic Notation "clears_all" :=
generalize ltac_mark;
clears_or_generalizes_all_core;
intro_until_mark.

clears_but H1 H2 .. HN clears all hypotheses except the one that are mentioned and those that cannot be cleared.

Ltac clears_but_core cont :=
generalize ltac_mark;
cont tt;
clears_or_generalizes_all_core;
intro_until_mark.

Tactic Notation "clears_but" :=
clears_but_core ltac:(fun _idtac).
Tactic Notation "clears_but" ident(H1) :=
clears_but_core ltac:(fun _gen H1).
Tactic Notation "clears_but" ident(H1) ident(H2) :=
clears_but_core ltac:(fun _gen H1 H2).
Tactic Notation "clears_but" ident(H1) ident(H2) ident(H3) :=
clears_but_core ltac:(fun _gen H1 H2 H3).
Tactic Notation "clears_but" ident(H1) ident(H2) ident(H3) ident(H4) :=
clears_but_core ltac:(fun _gen H1 H2 H3 H4).
Tactic Notation "clears_but" ident(H1) ident(H2) ident(H3) ident(H4) ident(H5) :=
clears_but_core ltac:(fun _gen H1 H2 H3 H4 H5).

Lemma demo_clears_all_and_clears_but :
x y:nat, y < 2 x = x x ≥ 2 x < 3 True.
Proof using.
introv M1 M2 M3. dup 6.
(* clears_all clears all hypotheses. *)
clears_all. auto.
(* clears_but H clears all but H *)
clears_but M3. auto.
clears_but y. auto.
clears_but x. auto.
clears_but M2 M3. auto.
clears_but x y. auto.
Qed.

clears_last clears the last hypothesis in the context. clears_last N clears the last N hypotheses in the context.

Tactic Notation "clears_last" :=
match goal with H: ?T _clear H end.

Ltac clears_last_base N :=
match nat_from_number N with
| 0 ⇒ idtac
| S ?pclears_last; clears_last_base p
end.

Tactic Notation "clears_last" constr(N) :=
clears_last_base N.

(* ********************************************************************** *)

# Tactics for development purposes

(* ---------------------------------------------------------------------- *)

## Skipping subgoals

DEPRECATED: the new "admit" tactics now works fine.
The skip tactic can be used at any time to admit the current goal. Using skip is much more efficient than using the Focus top-level command to reach a particular subgoal.
There are two possible implementations of skip. The first one relies on the use of an existential variable. The second one relies on an axiom of type False. Remark that the builtin tactic admit is not applicable if the current goal contains uninstantiated variables.
The advantage of the first technique is that a proof using skip must end with Admitted, since Qed will be rejected with the message "uninstantiated existential variables". It is thereafter clear that the development is incomplete.
The advantage of the second technique is exactly the converse: one may conclude the proof using Qed, and thus one saves the pain from renaming Qed into Admitted and vice-versa all the time. Note however, that it is still necessary to instantiate all the existential variables introduced by other tactics in order for Qed to be accepted.
The two implementation are provided, so that you can select the one that suits you best. By default skip' uses the first implementation, and skip uses the second implementation.

Ltac skip_with_existential :=
match goal with ?G
let H := fresh in evar(H:G); eexact H end.

(* TO BE DEPRECATED: *)
Variable skip_axiom : False.
(* To obtain a safe development, change to skip_axiom : True *)
Ltac skip_with_axiom :=
elimtype False; apply skip_axiom.

Tactic Notation "skip" :=
skip_with_axiom.
Tactic Notation "skip'" :=
skip_with_existential.

(* SF DOES NOT NEED THIS
(* For backward compatibility *)
Tactic Notation "admit" :=
skip.
*)

demo is like admit but it documents the fact that admit is intended
Tactic Notation "demo" :=
skip.

skip H: T adds an assumption named H of type T to the current context, blindly assuming that it is true. skip: T and skip H_asserts: T and skip_asserts: T are other possible syntax. Note that H may be an intro pattern. The syntax skip H1 .. HN: T can be used when T is a conjunction of N items.

Tactic Notation "skip" simple_intropattern(I) ":" constr(T) :=
asserts I: T; [ skip | ].
Tactic Notation "skip" ":" constr(T) :=
let H := fresh in skip H: T.
Tactic Notation "skip" "¬" ":" constr(T) :=
skip: T; auto_tilde.
Tactic Notation "skip" "*" ":" constr(T) :=
skip: T; auto_star.

Tactic Notation "skip" simple_intropattern(I1)
simple_intropattern(I2) ":" constr(T) :=
skip [I1 I2]: T.
Tactic Notation "skip" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3) ":" constr(T) :=
skip [I1 [I2 I3]]: T.
Tactic Notation "skip" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) ":" constr(T) :=
skip [I1 [I2 [I3 I4]]]: T.
Tactic Notation "skip" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) simple_intropattern(I5) ":" constr(T) :=
skip [I1 [I2 [I3 [I4 I5]]]]: T.
Tactic Notation "skip" simple_intropattern(I1)
simple_intropattern(I2) simple_intropattern(I3)
simple_intropattern(I4) simple_intropattern(I5)
simple_intropattern(I6) ":" constr(T) :=
skip [I1 [I2 [I3 [I4 [I5 I6]]]]]: T.

Tactic Notation "skip_asserts" simple_intropattern(I) ":" constr(T) :=
skip I: T.
Tactic Notation "skip_asserts" ":" constr(T) :=
skip: T.

skip_cuts T simply replaces the current goal with T.

Tactic Notation "skip_cuts" constr(T) :=
cuts: T; [ skip | ].

skip_goal H applies to any goal. It simply assumes the current goal to be true. The assumption is named "H". It is useful to set up proof by induction or coinduction. Syntax skip_goal is also accepted.

Tactic Notation "skip_goal" ident(H) :=
match goal with ?Gskip H: G end.

Tactic Notation "skip_goal" :=
let IH := fresh "IH" in skip_goal IH.

skip_rewrite T can be applied when T is an equality. It blindly assumes this equality to be true, and rewrite it in the goal.

Tactic Notation "skip_rewrite" constr(T) :=
let M := fresh in skip_asserts M: T; rewrite M; clear M.

skip_rewrite T in H is similar as rewrite_skip, except that it rewrites in hypothesis H.

Tactic Notation "skip_rewrite" constr(T) "in" hyp(H) :=
let M := fresh in skip_asserts M: T; rewrite M in H; clear M.

skip_rewrites_all T is similar as rewrite_skip, except that it rewrites everywhere (goal and all hypotheses).

Tactic Notation "skip_rewrite_all" constr(T) :=
let M := fresh in skip_asserts M: T; rewrite_all M; clear M.

skip_induction E applies to any goal. It simply assumes the current goal to be true (the assumption is named "IH" by default), and call destruct E instead of induction E. It is useful to try and set up a proof by induction first, and fix the applications of the induction hypotheses during a second pass on the Proof using.
(* TODO: deprecated *)

Tactic Notation "skip_induction" constr(E) :=
let IH := fresh "IH" in skip_goal IH; destruct E.

Tactic Notation "skip_induction" constr(E) "as" simple_intropattern(I) :=
let IH := fresh "IH" in skip_goal IH; destruct E as I.

(* ********************************************************************** *)

# Compatibility with standard library

The module Program contains definitions that conflict with the current module. If you import Program, either directly or indirectly (e.g., through Setoid or ZArith), you will need to import the compability definitions through the top-level command: Import LibTacticsCompatibility.

Module LibTacticsCompatibility.
Tactic Notation "apply" "*" constr(H) :=
sapply H; auto_star.
Tactic Notation "subst" "*" :=
subst; auto_star.
End LibTacticsCompatibility.

Open Scope nat_scope.

(* ********************************************************************** *)

# Additional notations for Coq

(* ---------------------------------------------------------------------- *)

## N-ary Existentials —TODO: DEPRECATED, Coq now supports it.

T1 ... TN, P is a shorthand for T1, ..., TN, P. Note that Coq.Program.Syntax already defines exists for arity up to 4.

(* SF DOES NOT NEED
Notation "'exists' x1 ',' P" :=
(exists x1, P)
(at level 200, x1 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 ',' P" :=
(exists x1, exists x2, P)
(at level 200, x1 ident, x2 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 x3 ',' P" :=
(exists x1, exists x2, exists x3, P)
(at level 200, x1 ident, x2 ident, x3 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 x3 x4 ',' P" :=
(exists x1, exists x2, exists x3, exists x4, P)
(at level 200, x1 ident, x2 ident, x3 ident, x4 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 x3 x4 x5 ',' P" :=
(exists x1, exists x2, exists x3, exists x4, exists x5, P)
(at level 200, x1 ident, x2 ident, x3 ident, x4 ident, x5 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 x3 x4 x5 x6 ',' P" :=
(exists x1, exists x2, exists x3, exists x4, exists x5, exists x6, P)
(at level 200, x1 ident, x2 ident, x3 ident, x4 ident, x5 ident,
x6 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 x3 x4 x5 x6 x7 ',' P" :=
(exists x1, exists x2, exists x3, exists x4, exists x5, exists x6
exists x7, P)
(at level 200, x1 ident, x2 ident, x3 ident, x4 ident, x5 ident,
x6 ident, x7 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 x3 x4 x5 x6 x7 x8 ',' P" :=
(exists x1, exists x2, exists x3, exists x4, exists x5, exists x6
exists x7, exists x8, P)
(at level 200, x1 ident, x2 ident, x3 ident, x4 ident, x5 ident,
x6 ident, x7 ident, x8 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 x3 x4 x5 x6 x7 x8 x9 ',' P" :=
(exists x1, exists x2, exists x3, exists x4, exists x5, exists x6
exists x7, exists x8, exists x9, P)
(at level 200, x1 ident, x2 ident, x3 ident, x4 ident, x5 ident,
x6 ident, x7 ident, x8 ident, x9 ident,
right associativity) : type_scope.
Notation "'exists' x1 x2 x3 x4 x5 x6 x7 x8 x9 x10 ',' P" :=
(exists x1, exists x2, exists x3, exists x4, exists x5, exists x6
exists x7, exists x8, exists x9, exists x10, P)
(at level 200, x1 ident, x2 ident, x3 ident, x4 ident, x5 ident,
x6 ident, x7 ident, x8 ident, x9 ident, x10 ident,
right associativity) : type_scope.

*)

(* ---------------------------------------------------------------------- *)

## 'let bindings (EXPERIMENTAL).

The syntax 'let x := v in e has the same meaning as let x := v in e except that the binding is implemented using a beta-redex that is not reduced automatically by simpl. The 'let construct therefore makes it possible to simplify or push to the context let-bindings one by one.
Definition of 'let

Definition let_binding (A B:Type) (v:A) (K:AB) := K v.

Notation "''let' x ':=' v 'in' e" := (let_binding v (fun xe))
(at level 69, x ident, right associativity,
format "'[v' '[' ''let' x ':=' v 'in' ']' '/' '[' e ']' ']'")
: let_scope.

Notation "''let' x ':' A ':=' v 'in' e" := (let_binding (v:A) (fun x:Ae))
(at level 69, x ident, right associativity,
format "'[v' '[' ''let' x ':' A ':=' v 'in' ']' '/' '[' e ']' ']'")
: let_scope.

Global Open Scope let_scope.

Lemma let_binding_unfold : (A B:Type) (v:A) (K:AB),
let_binding v K = K v.
Proof using. reflexivity. Qed.

Ltac let_get_fresh_binding_name K :=
match K with (fun x_) ⇒ let y := fresh x in y end.

let_simpl finds the first occurence of a 'let binding and substitutes it.

Tactic Notation "let_simpl" "in" hyp(H) :=
match type of H with context [ let_binding ?v ?K ] ⇒
changes (let_binding v K) with (K v) in H
end.

Tactic Notation "let_simpl" :=
match goal with
| context [ let_binding ?v ?K ] ⇒
changes (let_binding v K) with (K v)
| H: context [ let_binding ?v ?K ] _
let_simpl in H
end.

Tactic Notation "let_simpl" constr(v) "in" hyp(H) :=
repeat match type of H with context [ let_binding v ?K ] ⇒
changes (let_binding v K) with (K v) in H
end.

Tactic Notation "let_simpl" constr(v) :=
repeat match goal with
| context [ let_binding v ?K ] ⇒
changes (let_binding v K) with (K v)
| H: context [ let_binding v ?K ] _
let_simpl v in H
end.

let_name finds the first occurence of a 'let binding and moves this binding to the proof context.

Tactic Notation "let_name" "in" hyp(H) :=
match type of H with context [ let_binding ?v ?K ] ⇒
let x := let_get_fresh_binding_name K in
set_eq x: v in H;
let_simpl in H
end.

Tactic Notation "let_name" "in" hyp(H) "as" ident(x) :=
match type of H with context [ let_binding ?v ?K ] ⇒
set_eq x: v in H;
let_simpl in H
end.

Tactic Notation "let_name" :=
match goal with
| context [ let_binding ?v ?K ] ⇒
let x := let_get_fresh_binding_name K in
set_eq x: v;
let_simpl
| H: context [ let_binding ?v ?K ] _
let_name in H
end.

Tactic Notation "let_name" "as" ident(x) :=
match goal with
| context [ let_binding ?v ?K ] ⇒
set_eq x: v;
let_simpl
| H: context [ let_binding ?v ?K ] _
let_name in H as x
end.

let_name_all finds the first occurence of a 'let binding, moves this binding to the proof context, and further simplify all the other 'let bindings that are binding the same value. (See LibFixDemos for a practical motivation.)

Tactic Notation "let_name_all" "in" hyp(H) :=
match type of H with context [ let_binding ?v ?K ] ⇒
let x := let_get_fresh_binding_name K in
set_eq x: v in H;
let_simpl x in H
end.

Tactic Notation "let_name_all" "in" hyp(H) "as" ident(x) :=
match type of H with context [ let_binding ?v ?K ] ⇒
set_eq x: v in H;
let_simpl x in H
end.

Tactic Notation "let_name_all" :=
match goal with
| context [ let_binding ?v ?K ] ⇒
let x := let_get_fresh_binding_name K in
set_eq x: v;
let_simpl x
| H: context [ let_binding ?v ?K ] _
let_name_all in H
end.

Tactic Notation "let_name_all" "as" ident(x) :=
match goal with
| context [ let_binding ?v ?K ] ⇒
set_eq x: v;
let_simpl x
| H: context [ let_binding ?v ?K ] _
let_name_all in H as x
end.

(* ---------------------------------------------------------------------- *)
(* Bugfix for f_equal and fequals; only supports up to arity 5 *)

Section FuncEq.
Variables (A1 A2 A3 A4 A5 B : Type).

Lemma func_eq_1 : (f:A1B) x1 y1,
x1 = y1
f x1 = f y1.
Proof. intros. subst¬. Qed.

Lemma func_eq_2 : (f:A1A2B) x1 y1 x2 y2,
x1 = y1 x2 = y2
f x1 x2 = f y1 y2.
Proof. intros. subst¬. Qed.

Lemma func_eq_3 : (f:A1A2A3B) x1 y1 x2 y2 x3 y3,
x1 = y1 x2 = y2 x3 = y3
f x1 x2 x3 = f y1 y2 y3.
Proof. intros. subst¬. Qed.

Lemma func_eq_4 : (f:A1A2A3A4B) x1 y1 x2 y2 x3 y3 x4 y4,
x1 = y1 x2 = y2 x3 = y3 x4 = y4
f x1 x2 x3 x4 = f y1 y2 y3 y4.
Proof. intros. subst¬. Qed.

Lemma func_eq_5 : (f:A1A2A3A4A5B) x1 y1 x2 y2 x3 y3 x4 y4 x5 y5,
x1 = y1 x2 = y2 x3 = y3 x4 = y4 x5 = y5
f x1 x2 x3 x4 x5 = f y1 y2 y3 y4 y5.
Proof. intros. subst¬. Qed.

End FuncEq.

Ltac f_equal_fixed :=
try (
first
[ apply func_eq_1
| apply func_eq_2
| apply func_eq_3
| apply func_eq_4
| apply func_eq_5 ];
try reflexivity).

Ltac fequal_base ::=
let go := f_equal_fixed; [ fequal_base | ] in
match goal with
| (_,_,_) = (_,_,_) ⇒ go
| (_,_,_,_) = (_,_,_,_) ⇒ go
| (_,_,_,_,_) = (_,_,_,_,_) ⇒ go
| (_,_,_,_,_,_) = (_,_,_,_,_,_) ⇒ go
| _f_equal_fixed
end.

(* ---------------------------------------------------------------------- *)
(* Bugfix for autorewrite in *, which is currently inefficient *)

Generalize all propositions into the goal

Ltac generalize_all_prop :=
repeat match goal with H: ?T _
match type of T with Prop
generalizes H
end end.

Work around for inefficiency bug of autorewrite in *. Usage, e.g.: Tactic Notation "rew_list" "in" "*" := autorewrite_in_star_patch ltac:(fun tt autorewrite with rew_list).

Ltac autorewrite_in_star_patch cont :=
generalize ltac_mark;
generalize_all_prop;
cont tt;
intro_until_mark.