227 lines
7.9 KiB
C++
227 lines
7.9 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 <string>
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#include "util/sstream.h"
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#include "kernel/kernel_exception.h"
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#include "kernel/instantiate.h"
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#include "kernel/inductive/inductive.h"
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#include "library/util.h"
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#include "library/projection.h"
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#include "library/module.h"
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#include "library/kernel_serializer.h"
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namespace lean {
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/** \brief This environment extension stores information about all projection functions
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defined in an environment object.
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*/
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struct projection_ext : public environment_extension {
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name_map<projection_info> m_info;
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projection_ext() {}
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};
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struct projection_ext_reg {
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unsigned m_ext_id;
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projection_ext_reg() {
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m_ext_id = environment::register_extension(std::make_shared<projection_ext>());
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}
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};
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static projection_ext_reg * g_ext = nullptr;
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static projection_ext const & get_extension(environment const & env) {
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return static_cast<projection_ext const &>(env.get_extension(g_ext->m_ext_id));
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}
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static environment update(environment const & env, projection_ext const & ext) {
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return env.update(g_ext->m_ext_id, std::make_shared<projection_ext>(ext));
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}
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static std::string * g_proj_key = nullptr;
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static environment save_projection_info_core(environment const & env, name const & p, name const & mk, unsigned nparams,
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unsigned i, bool inst_implicit) {
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projection_ext ext = get_extension(env);
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ext.m_info.insert(p, projection_info(mk, nparams, i, inst_implicit));
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return update(env, ext);
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}
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environment save_projection_info(environment const & env, name const & p, name const & mk, unsigned nparams, unsigned i, bool inst_implicit) {
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environment new_env = save_projection_info_core(env, p, mk, nparams, i, inst_implicit);
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return module::add(new_env, *g_proj_key, [=](environment const &, serializer & s) {
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s << p << mk << nparams << i << inst_implicit;
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});
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}
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projection_info const * get_projection_info(environment const & env, name const & p) {
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projection_ext const & ext = get_extension(env);
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return ext.m_info.find(p);
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}
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name_map<projection_info> const & get_projection_info_map(environment const & env) {
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return get_extension(env).m_info;
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}
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static void projection_info_reader(deserializer & d, shared_environment & senv,
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std::function<void(asynch_update_fn const &)> &,
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std::function<void(delayed_update_fn const &)> &) {
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name p, mk; unsigned nparams, i; bool inst_implicit;
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d >> p >> mk >> nparams >> i >> inst_implicit;
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senv.update([=](environment const & env) -> environment {
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return save_projection_info_core(env, p, mk, nparams, i, inst_implicit);
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});
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}
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/** \brief Return true iff the type named \c S can be viewed as
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a structure in the given environment.
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If not, generate an error message using \c pos.
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*/
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bool is_structure_like(environment const & env, name const & S) {
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optional<inductive::inductive_decls> idecls = inductive::is_inductive_decl(env, S);
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if (!idecls || length(std::get<2>(*idecls)) != 1)
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return false;
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inductive::inductive_decl decl = head(std::get<2>(*idecls));
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return length(inductive::inductive_decl_intros(decl)) == 1 && *inductive::get_num_indices(env, S) == 0;
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}
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projection_info const * projection_converter::is_projection(expr const & e) const {
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expr const & f = get_app_fn(e);
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if (is_constant(f))
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return m_proj_info.find(const_name(f));
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else
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return nullptr;
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}
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bool projection_converter::is_opaque(declaration const & d) const {
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return m_proj_info.find(d.get_name()) != nullptr;
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}
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optional<pair<expr, constraint_seq>> projection_converter::reduce_projection(expr const & t) {
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projection_info const * info = is_projection(t);
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if (!info)
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return optional<pair<expr, constraint_seq>>();
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buffer<expr> args;
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get_app_args(t, args);
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if (args.size() <= info->m_nparams) {
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return optional<pair<expr, constraint_seq>>();
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}
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unsigned mkidx = info->m_nparams;
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expr const & mk = args[mkidx];
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pair<expr, constraint_seq> new_mk_cs = whnf(mk);
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expr new_mk = new_mk_cs.first;
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expr const & new_mk_fn = get_app_fn(new_mk);
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if (!is_constant(new_mk_fn) || const_name(new_mk_fn) != info->m_constructor) {
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return optional<pair<expr, constraint_seq>>();
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}
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buffer<expr> mk_args;
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get_app_args(new_mk, mk_args);
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unsigned i = info->m_nparams + info->m_i;
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if (i >= mk_args.size()) {
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return optional<pair<expr, constraint_seq>>();
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}
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expr r = mk_args[i];
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r = mk_app(r, args.size() - mkidx - 1, args.data() + mkidx + 1);
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return optional<pair<expr, constraint_seq>>(r, new_mk_cs.second);
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}
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optional<pair<expr, constraint_seq>> projection_converter::norm_ext(expr const & e) {
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if (auto r = reduce_projection(e)) {
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return r;
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} else {
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return default_converter::norm_ext(e);
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}
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}
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bool projection_converter::postpone_is_def_eq(expr const & t, expr const & s) {
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if (has_expr_metavar(t) || has_expr_metavar(s)) {
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auto it1 = is_projection(t);
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auto it2 = is_projection(s);
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if (it1 && it2) {
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return true;
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}
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if (it1 && is_stuck(t, *m_tc))
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return true;
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if (it2 && is_stuck(s, *m_tc))
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return true;
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}
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return default_converter::postpone_is_def_eq(t, s);
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}
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// Apply lazy delta-reduction and then normalizer extensions
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lbool projection_converter::reduce_def_eq(expr & t_n, expr & s_n, constraint_seq & cs) {
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while (true) {
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// first, keep applying lazy delta-reduction while applicable
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lbool r = lazy_delta_reduction(t_n, s_n, cs);
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if (r != l_undef) return r;
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auto p_t = reduce_projection(t_n);
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auto p_s = reduce_projection(s_n);
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if (p_t && p_s) {
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t_n = whnf_core(p_t->first);
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s_n = whnf_core(p_s->first);
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cs += p_t->second;
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cs += p_s->second;
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} else if (p_t || p_s) {
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expr const & f_t = get_app_fn(t_n);
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expr const & f_s = get_app_fn(s_n);
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if (is_constant(f_t) && is_constant(f_s) && const_name(f_t) == const_name(f_s) &&
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(p_t || is_stuck(t_n, *m_tc)) && (p_s || is_stuck(s_n, *m_tc))) {
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// treat it as a delta-delta step
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return l_undef;
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}
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if (p_t) {
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t_n = whnf_core(p_t->first);
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cs += p_t->second;
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} else if (p_s) {
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s_n = whnf_core(p_s->first);
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cs += p_s->second;
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} else {
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lean_unreachable();
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}
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} else {
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auto new_t_n = d_norm_ext(t_n, cs);
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auto new_s_n = d_norm_ext(s_n, cs);
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if (!new_t_n && !new_s_n)
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return l_undef;
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if (new_t_n) {
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t_n = whnf_core(*new_t_n);
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}
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if (new_s_n) {
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s_n = whnf_core(*new_s_n);
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}
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}
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r = quick_is_def_eq(t_n, s_n, cs);
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if (r != l_undef) return r;
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}
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}
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optional<expr> projection_converter::is_stuck(expr const & e, type_checker & c) {
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projection_info const * info = is_projection(e);
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if (!info)
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return default_converter::is_stuck(e, c);
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buffer<expr> args;
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get_app_args(e, args);
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if (args.size() <= info->m_nparams)
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return none_expr();
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expr mk = whnf(args[info->m_nparams], c).first;
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return c.is_stuck(mk);
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}
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projection_converter::projection_converter(environment const & env):
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default_converter(env, true) {
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m_proj_info = ::lean::get_extension(env).m_info;
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}
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void initialize_projection() {
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g_ext = new projection_ext_reg();
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g_proj_key = new std::string("proj");
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register_module_object_reader(*g_proj_key, projection_info_reader);
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}
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void finalize_projection() {
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delete g_proj_key;
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delete g_ext;
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}
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}
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