lean2/library/init/tactic.lean

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/-
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Module: init.tactic
Author: Leonardo de Moura
This is just a trick to embed the 'tactic language' as a Lean
expression. We should view 'tactic' as automation that when execute
produces a term. tactic.builtin is just a "dummy" for creating the
definitions that are actually implemented in C++
-/
prelude
import init.datatypes init.reserved_notation init.num
inductive tactic :
Type := builtin : tactic
namespace tactic
-- Remark the following names are not arbitrary, the tactic module
-- uses them when converting Lean expressions into actual tactic objects.
-- The bultin 'by' construct triggers the process of converting a
-- a term of type 'tactic' into a tactic that sythesizes a term
opaque definition and_then (t1 t2 : tactic) : tactic := builtin
opaque definition or_else (t1 t2 : tactic) : tactic := builtin
opaque definition append (t1 t2 : tactic) : tactic := builtin
opaque definition interleave (t1 t2 : tactic) : tactic := builtin
opaque definition par (t1 t2 : tactic) : tactic := builtin
opaque definition fixpoint (f : tactic → tactic) : tactic := builtin
opaque definition repeat (t : tactic) : tactic := builtin
opaque definition at_most (t : tactic) (k : num) : tactic := builtin
opaque definition discard (t : tactic) (k : num) : tactic := builtin
opaque definition focus_at (t : tactic) (i : num) : tactic := builtin
opaque definition try_for (t : tactic) (ms : num) : tactic := builtin
opaque definition now : tactic := builtin
opaque definition assumption : tactic := builtin
opaque definition eassumption : tactic := builtin
opaque definition state : tactic := builtin
opaque definition fail : tactic := builtin
opaque definition id : tactic := builtin
opaque definition beta : tactic := builtin
opaque definition info : tactic := builtin
opaque definition whnf : tactic := builtin
opaque definition rotate_left (k : num) := builtin
opaque definition rotate_right (k : num) := builtin
definition rotate (k : num) := rotate_left k
-- This is just a trick to embed expressions into tactics.
-- The nested expressions are "raw". They tactic should
-- elaborate them when it is executed.
inductive expr : Type :=
builtin : expr
opaque definition apply (e : expr) : tactic := builtin
opaque definition rapply (e : expr) : tactic := builtin
opaque definition fapply (e : expr) : tactic := builtin
opaque definition rename (a b : expr) : tactic := builtin
opaque definition intro (e : expr) : tactic := builtin
opaque definition generalize (e : expr) : tactic := builtin
opaque definition clear (e : expr) : tactic := builtin
opaque definition revert (e : expr) : tactic := builtin
opaque definition unfold (e : expr) : tactic := builtin
opaque definition exact (e : expr) : tactic := builtin
-- rexact is similar to exact, but the goal type is enforced during elaboration
opaque definition sexact (e : expr) : tactic := builtin
opaque definition trace (s : string) : tactic := builtin
inductive expr_list : Type :=
| nil : expr_list
| cons : expr → expr_list → expr_list
-- auxiliary type used to mark optional list of arguments
definition opt_expr_list := expr_list
-- rewrite_tac is just a marker for the builtin 'rewrite' notation
-- used to create instances of this tactic.
opaque definition rewrite_tac (e : expr_list) : tactic := builtin
opaque definition cases (id : expr) (ids : opt_expr_list) : tactic := builtin
opaque definition intros (ids : opt_expr_list) : tactic := builtin
opaque definition generalizes (es : expr_list) : tactic := builtin
opaque definition clears (ids : expr_list) : tactic := builtin
opaque definition reverts (ids : expr_list) : tactic := builtin
opaque definition change (e : expr) : tactic := builtin
opaque definition assert_hypothesis (id : expr) (e : expr) : tactic := builtin
infixl `;`:15 := and_then
notation `[` h `|` r:(foldl `|` (e r, or_else r e) h) `]` := r
definition try (t : tactic) : tactic := [t | id]
definition repeat1 (t : tactic) : tactic := t ; repeat t
definition focus (t : tactic) : tactic := focus_at t 0
definition determ (t : tactic) : tactic := at_most t 1
definition trivial : tactic := [ apply eq.refl | apply true.intro | assumption ]
definition do (n : num) (t : tactic) : tactic :=
nat.rec id (λn t', (t;t')) (nat.of_num n)
end tactic