Fsub.ExtendedBase.Tactics

Helper tactic definitions for Fsub.

Authors: Edward Lee, Ondrej Lhotak, Yaoyu Zhao

This work is based off the POPL'08 Coq tutorial authored by: Brian Aydemir and Arthur Chargu\'eraud, with help from Aaron Bohannon, Jeffrey Vaughan, and Dimitrios Vytiniotis.

This file contains a number of definitions, tactics, and lemmas that are based only on the syntax of the language at hand. While the exact statements of everything here would change for a different language, the general structure of this file (i.e., the sequence of definitions, tactics, and lemmas) would remain the same.

Table of contents:

Free variables
Substitution
The "gather_atoms" tactic
Properties of opening and substitution
Local closure is preserved under substitution
Additional properties of normal forms under opening and substitution
Automation
Properties of body_e

Require Export FqMeta.Metatheory.

Ltac autodestruct_if :=
  repeat match goal with
  | H: context X [?A == ?B] |- _ => destruct ( A === B ); subst; eauto;
    try solve [inversion H]
  end.

Borrowed from

https://gitlab.mpi-sws.org/iris/stdpp/-/blob/master/theories/tactics.v

The tactic select pat tac finds the last (i.e., bottommost) hypothesis matching pat and passes it to the continuation tac. Its main advantage over using match goal with directly is that it is shorter. If pat matches multiple hypotheses and tac fails, then select tac will not backtrack on subsequent matching hypotheses.

The tactic select is written in CPS and does not return the name of the hypothesis due to limitations in the Ltac1 tactic runtime (see https://gitter.im/coq/coq?at=5e96c82f85b01628f04bbb89).

Tactic Notation "select" open_constr(pat) tactic3(tac) :=
lazymatch goal with

Before running tac on the hypothesis H we must first unify the pattern pat with the term it matched against. This forces every evar coming from pat (and in particular from the holes _ it contains and from the implicit arguments it uses) to be instantiated. If we do not do so then shelved goals are produced for every such evar.

| H : pat |- _ => let T := (type of H) in unify T pat; tac H
end.

select_revert reverts the first hypothesis matching pat.

Tactic Notation "revert" "select" open_constr(pat) := select pat (fun H => revert H).

Tactic Notation "rename" "select" open_constr(pat) "into" ident(name) :=
  select pat (fun H => rename H into name).

Tactic Notation "inversion" "select" open_constr(pat) :=
  select pat (fun H => inversion H).

Tactic Notation "destruct" "select" open_constr(pat) :=
  select pat (fun H => destruct H).

Tactic Notation "destruct" "select" open_constr(pat) "as" simple_intropattern(destruct_pat) :=
  select pat (fun H => destruct H as destruct_pat).