44 lines
1.5 KiB
C++
44 lines
1.5 KiB
C++
/*
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Copyright (c) 2015 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#include "kernel/inductive/inductive.h"
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#include "library/constants.h"
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#include "library/util.h"
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#include "library/reducible.h"
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#include "library/tactic/intros_tactic.h"
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#include "library/tactic/expr_to_tactic.h"
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#include "kernel/kernel_exception.h"
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namespace lean {
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tactic exfalso_tactic() {
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auto fn = [=](environment const & env, io_state const &, proof_state const & s) {
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goals const & gs = s.get_goals();
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if (empty(gs)) {
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throw_no_goal_if_enabled(s);
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return optional<proof_state>();
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}
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goal const & g = head(gs);
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expr const & t = g.get_type();
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substitution subst = s.get_subst();
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name_generator ngen = s.get_ngen();
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auto tc = mk_type_checker(env, ngen.mk_child());
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expr false_expr = mk_false(env);
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expr new_meta = g.mk_meta(ngen.next(), false_expr);
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goal new_goal(new_meta, false_expr);
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assign(subst, g, mk_false_rec(*tc, new_meta, t));
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return some(proof_state(s, goals(new_goal, tail(gs)), subst, ngen));
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};
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return tactic01(fn);
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}
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void initialize_exfalso_tactic() {
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register_tac(name{"tactic", "exfalso"},
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[](type_checker &, elaborate_fn const &, expr const &, pos_info_provider const *) {
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return exfalso_tactic();
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});
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}
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void finalize_exfalso_tactic() {
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}
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}
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