57 lines
2.3 KiB
C++
57 lines
2.3 KiB
C++
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/*
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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 "library/constants.h"
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#include "kernel/type_checker.h"
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#include "library/reducible.h"
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#include "library/tactic/tactic.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 change_goal_tactic(elaborate_fn const & elab, expr const & e) {
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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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goals const & gs = new_s.get_goals();
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if (!gs) {
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throw_no_goal_if_enabled(s);
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return none_proof_state();
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}
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expr t = head(gs).get_type();
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bool report_unassigned = true;
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if (auto new_e = elaborate_with_respect_to(env, ios, elab, new_s, e, none_expr(), report_unassigned)) {
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goals const & gs = new_s.get_goals();
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goal const & g = head(gs);
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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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auto tc = mk_type_checker(env, ngen.mk_child());
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constraint_seq cs;
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if (tc->is_def_eq(t, *new_e, justification(), cs) && !cs) {
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expr M = g.mk_meta(ngen.next(), *new_e);
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goal new_g(M, *new_e);
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expr val = g.abstract(M);
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subst.assign(g.get_name(), val);
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return some(proof_state(new_s, cons(new_g, tail(gs)), subst, ngen));
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} else {
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// generate error
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return none_proof_state();
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}
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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_change_tactic() {
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register_tac(get_tactic_change_goal_name(),
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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 'change' tactic, invalid argument");
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return change_goal_tactic(fn, get_tactic_expr_expr(app_arg(e)));
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});
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}
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void finalize_change_tactic() {
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}
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}
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