51 lines
1.8 KiB
C++
51 lines
1.8 KiB
C++
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/*
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Copyright (c) 2014 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/type_checker.h"
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#include "library/tactic/tactic.h"
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#include "library/tactic/expr_to_tactic.h"
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namespace lean {
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tactic exact_tactic(expr const & _e) {
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return tactic01([=](environment const & env, io_state const &, proof_state const & s) {
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type_checker tc(env);
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substitution subst = s.get_subst();
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goals const & gs = s.get_goals();
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goal const & g = head(gs);
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expr e = subst.instantiate(_e);
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auto e_t_cs = tc.infer(e);
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expr e_t = subst.instantiate(e_t_cs.first);
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expr t = subst.instantiate(g.get_type());
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auto dcs = tc.is_def_eq(e_t, t);
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if (dcs.first && !dcs.second && !e_t_cs.second) {
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expr new_p = g.abstract(e);
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check_has_no_local(new_p, _e, "exact");
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subst.assign(g.get_name(), new_p);
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return some(proof_state(s, tail(gs), subst));
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} else {
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return none_proof_state();
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}
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});
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}
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static expr * g_exact_tac_fn = nullptr;
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expr const & get_exact_tac_fn() { return *g_exact_tac_fn; }
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void initialize_exact_tactic() {
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name exact_tac_name({"tactic", "exact"});
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g_exact_tac_fn = new expr(Const(exact_tac_name));
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register_tac(exact_tac_name,
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[](type_checker &, elaborate_fn const &, expr const & e, pos_info_provider const *) {
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// TODO(Leo): use elaborate_fn
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return exact_tactic(app_arg(e));
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});
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}
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void finalize_exact_tactic() {
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delete g_exact_tac_fn;
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}
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}
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