-- Copyright (c) 2014 Microsoft Corporation. All rights reserved.
-- Released under Apache 2.0 license as described in the file LICENSE.
-- Author: Leonardo de Moura
import logic string num
using string
using num

namespace tactic
-- 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.
-- builtin_tactic is just a "dummy" for creating the
-- definitions that are actually implemented in C++
inductive tactic : Type :=
| builtin_tactic : 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
definition and_then   (t1 t2 : tactic) : tactic := builtin_tactic
definition or_else    (t1 t2 : tactic) : tactic := builtin_tactic
definition append     (t1 t2 : tactic) : tactic := builtin_tactic
definition interleave (t1 t2 : tactic) : tactic := builtin_tactic
definition par        (t1 t2 : tactic) : tactic := builtin_tactic
definition repeat     (t : tactic) : tactic := builtin_tactic
definition at_most    (t : tactic) (k : num)  : tactic := builtin_tactic
definition discard    (t : tactic) (k : num)  : tactic := builtin_tactic
definition focus_at   (t : tactic) (i : num)  : tactic := builtin_tactic
definition try_for    (t : tactic) (ms : num) : tactic := builtin_tactic
definition now        : tactic := builtin_tactic
definition assumption : tactic := builtin_tactic
definition state      : tactic := builtin_tactic
definition fail       : tactic := builtin_tactic
definition id         : tactic := builtin_tactic
definition beta       : tactic := builtin_tactic
definition apply      {B : Type} (b : B) : tactic := builtin_tactic
definition unfold     {B : Type} (b : B) : tactic := builtin_tactic
definition exact      {B : Type} (b : B) : tactic := builtin_tactic
definition trace      (s : string) : tactic := builtin_tactic
infixl `;`:200         := and_then
infixl `|`:100         := or_else
notation `!` t:max     := repeat t
notation `⟦` t `⟧`     := apply t
definition try        (t : tactic) : tactic := t | id
notation `?` t:max     := try t
definition repeat1    (t : tactic) : tactic := t ; !t
definition focus      (t : tactic) : tactic := focus_at t 0
definition determ     (t : tactic) : tactic := at_most t 1
end