lean4-htt/src/library/noncomputable.cpp

127 lines
3.9 KiB
C++

/*
Copyright (c) 2015 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <utility>
#include <string>
#include "util/sstream.h"
#include "kernel/for_each_fn.h"
#include "kernel/type_checker.h"
#include "library/module.h"
#include "library/util.h"
#include "library/fingerprint.h"
#include "library/library_system.h"
namespace lean {
struct noncomputable_ext : public environment_extension {
name_set m_noncomputable;
noncomputable_ext() {}
};
struct noncomputable_ext_reg {
unsigned m_ext_id;
noncomputable_ext_reg() {
m_ext_id = environment::register_extension(std::make_shared<noncomputable_ext>());
}
};
static noncomputable_ext_reg * g_ext = nullptr;
static noncomputable_ext const & get_extension(environment const & env) {
return static_cast<noncomputable_ext const &>(env.get_extension(g_ext->m_ext_id));
}
static environment update(environment const & env, noncomputable_ext const & ext) {
return env.update(g_ext->m_ext_id, std::make_shared<noncomputable_ext>(ext));
}
struct noncomputable_modification : public modification {
LEAN_MODIFICATION("ncomp")
name m_decl;
noncomputable_modification() {}
noncomputable_modification(name const & decl) : m_decl(decl) {}
void perform(environment & env) const override {
noncomputable_ext ext = get_extension(env);
ext.m_noncomputable.insert(m_decl);
env = update(env, ext);
}
void serialize(serializer & s) const override {
s << m_decl;
}
static std::shared_ptr<modification const> deserialize(deserializer & d) {
return std::make_shared<noncomputable_modification>(read_name(d));
}
};
static bool is_noncomputable(type_checker & tc, noncomputable_ext const & ext, name const & n) {
environment const & env = tc.env();
if (ext.m_noncomputable.contains(n))
return true;
declaration const & d = env.get(n);
if (!d.is_trusted()) {
return false; /* ignore nontrusted definitions */
} else if (d.is_axiom() && !tc.is_prop(d.get_type())) {
return true;
} else if (d.is_constant_assumption()) {
return !env.is_builtin(d.get_name()) && !is_system_builtin(d.get_name()) && !tc.is_prop(d.get_type());
} else {
return false;
}
}
bool is_noncomputable(environment const & env, name const & n) {
type_checker tc(env);
auto ext = get_extension(env);
return is_noncomputable(tc, ext, n);
}
bool is_marked_noncomputable(environment const & env, name const & n) {
auto ext = get_extension(env);
return ext.m_noncomputable.contains(n);
}
environment mark_noncomputable(environment const & env, name const & n) {
auto ext = get_extension(env);
ext.m_noncomputable.insert(n);
environment new_env = update(env, ext);
return module::add(new_env, std::make_shared<noncomputable_modification>(n));
}
optional<name> get_noncomputable_reason(environment const & env, name const & n) {
declaration const & d = env.get(n);
if (!d.is_definition())
return optional<name>();
type_checker tc(env);
if (tc.is_prop(d.get_type()))
return optional<name>(); // definition is a proposition, then do nothing
expr const & v = d.get_value();
auto ext = get_extension(env);
optional<name> r;
for_each(v, [&](expr const & e, unsigned) {
if (is_constant(e) && is_noncomputable(tc, ext, const_name(e))) {
r = const_name(e);
}
return true;
});
return r;
}
bool check_computable(environment const & env, name const & n) {
return !get_noncomputable_reason(env, n);
}
void initialize_noncomputable() {
g_ext = new noncomputable_ext_reg();
noncomputable_modification::init();
}
void finalize_noncomputable() {
noncomputable_modification::finalize();
delete g_ext;
}
}