57 lines
2.3 KiB
C++
57 lines
2.3 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/abstract.h"
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#include "library/reducible.h"
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#include "library/tactic/elaborate.h"
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#include "library/tactic/expr_to_tactic.h"
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namespace lean {
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tactic generalize_tactic(elaborate_fn const & elab, expr const & e, name const & x) {
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return tactic01([=](environment const & env, io_state const & ios, proof_state const & s) {
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proof_state new_s = s;
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if (auto new_e = elaborate_with_respect_to(env, ios, elab, new_s, e)) {
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name_generator ngen = new_s.get_ngen();
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substitution subst = new_s.get_subst();
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goals const & gs = new_s.get_goals();
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goal const & g = head(gs);
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auto tc = mk_type_checker(env, ngen.mk_child());
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auto e_t_cs = tc->infer(*new_e);
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if (e_t_cs.second)
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return none_proof_state(); // constraints were generated
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expr e_t = e_t_cs.first;
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expr t = subst.instantiate(g.get_type());
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name n;
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if (is_constant(e))
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n = const_name(e);
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else if (is_local(e))
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n = local_pp_name(e);
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else
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n = x;
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expr new_t = mk_pi(n, e_t, abstract(t, *new_e));
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expr new_m = g.mk_meta(ngen.next(), new_t);
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expr new_v = g.abstract(mk_app(new_m, *new_e));
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subst.assign(g.get_name(), new_v);
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goal new_g(new_m, new_t);
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return some(proof_state(new_s, goals(new_g, tail(gs)), subst, ngen));
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}
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return none_proof_state();
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});
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}
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void initialize_generalize_tactic() {
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register_tac(name({"tactic", "generalize"}),
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[](type_checker &, elaborate_fn const & fn, expr const & e, pos_info_provider const *) {
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check_tactic_expr(app_arg(e), "invalid 'generalize' tactic, invalid argument");
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// TODO(Leo): allow user to provide name to abstract variable
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return generalize_tactic(fn, get_tactic_expr_expr(app_arg(e)), "x");
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});
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}
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void finalize_generalize_tactic() {
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}
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}
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