63 lines
2.7 KiB
C++
63 lines
2.7 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 "kernel/abstract.h"
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#include "library/constants.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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expr mk_let_tactic_expr(name const & id, expr const & e) {
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return mk_app(mk_constant(get_tactic_lettac_name()),
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mk_constant(id), e);
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}
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tactic let_tactic(elaborate_fn const & elab, name const & id, expr const & e) {
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return tactic01([=](environment const & env, io_state const &, 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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goal const & g = head(gs);
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name_generator ngen = s.get_ngen();
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bool report_unassigned = true;
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auto ecs = elab(g, ngen.mk_child(), e, none_expr(), report_unassigned);
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if (ecs.second)
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throw_tactic_exception_if_enabled(s, "invalid 'let' tactic, fail to resolve generated constraints");
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expr new_e = ecs.first;
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auto tc = mk_type_checker(env, ngen.mk_child(), s.relax_main_opaque());
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expr new_e_type = tc->infer(new_e).first;
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expr new_local = mk_local(ngen.next(), id, new_e_type, binder_info());
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buffer<expr> hyps;
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g.get_hyps(hyps);
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hyps.push_back(new_local);
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expr new_mvar = mk_metavar(ngen.next(), Pi(hyps, g.get_type()));
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hyps.pop_back();
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expr new_meta_core = mk_app(new_mvar, hyps);
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expr new_meta = mk_app(new_meta_core, new_local);
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goal new_goal(new_meta, g.get_type());
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substitution new_subst = new_s.get_subst();
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assign(new_subst, g, mk_app(new_meta_core, new_e));
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return some_proof_state(proof_state(s, cons(new_goal, tail(gs)), new_subst, ngen));
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});
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}
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void initialize_let_tactic() {
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register_tac(get_tactic_lettac_name(),
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[](type_checker &, elaborate_fn const & fn, expr const & e, pos_info_provider const *) {
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name id = tactic_expr_to_id(app_arg(app_fn(e)), "invalid 'let' tactic, argument must be an identifier");
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check_tactic_expr(app_arg(e), "invalid 'let' tactic, argument must be an expression");
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return let_tactic(fn, id, get_tactic_expr_expr(app_arg(e)));
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});
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}
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void finalize_let_tactic() {
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}
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}
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