lean2/src/kernel/level.cpp

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/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <algorithm>
#include <vector>
#include "util/safe_arith.h"
#include "util/buffer.h"
#include "util/rc.h"
#include "util/list.h"
#include "util/debug.h"
#include "util/hash.h"
#include "util/object_serializer.h"
#include "util/interrupt.h"
#include "kernel/level.h"
namespace lean {
level_cell const & to_cell(level const & l) {
return *l.m_ptr;
}
/** \brief Base class for representing universe level terms. */
struct level_cell {
void dealloc();
MK_LEAN_RC()
level_kind m_kind;
unsigned m_hash;
level_cell(level_kind k, unsigned h):m_rc(1), m_kind(k), m_hash(h) {}
};
struct level_composite : public level_cell {
unsigned m_depth;
unsigned m_has_param:1;
unsigned m_has_meta:1;
level_composite(level_kind k, unsigned h, unsigned d, bool has_param, bool has_meta):
level_cell(k, h), m_depth(d), m_has_param(has_param), m_has_meta(has_meta) {}
};
static bool is_composite(level const & l) {
switch (kind(l)) {
case level_kind::Succ: case level_kind::Max: case level_kind::IMax:
return true;
case level_kind::Param: case level_kind::Meta: case level_kind::Zero:
return false;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
static level_composite const & to_composite(level const & l) {
lean_assert(is_composite(l));
return static_cast<level_composite const &>(to_cell(l));
}
struct level_succ : public level_composite {
level m_l;
bool m_explicit;
level_succ(level const & l):
level_composite(level_kind::Succ, hash(hash(l), 17u), get_depth(l) + 1, has_param(l), has_meta(l)),
m_l(l),
m_explicit(is_explicit(l)) {}
};
level_succ const & to_level_succ(level const & l) { lean_assert(is_succ(l)); return static_cast<level_succ const &>(to_cell(l)); }
level const & succ_of(level const & l) { return to_level_succ(l).m_l; }
struct level_max_core : public level_composite {
level m_lhs;
level m_rhs;
level_max_core(bool imax, level const & l1, level const & l2):
level_composite(imax ? level_kind::IMax : level_kind::Max,
hash(hash(l1), hash(l2)),
std::max(get_depth(l1), get_depth(l2)) + 1,
has_param(l1) || has_param(l2),
has_meta(l1) || has_meta(l2)),
m_lhs(l1), m_rhs(l2) {
lean_assert(!is_explicit(l1) || !is_explicit(l2));
}
};
static level_max_core const & to_max_core(level const & l) {
lean_assert(is_max(l) || is_imax(l));
return static_cast<level_max_core const &>(to_cell(l));
}
level const & max_lhs(level const & l) { lean_assert(is_max(l)); return to_max_core(l).m_lhs; }
level const & max_rhs(level const & l) { lean_assert(is_max(l)); return to_max_core(l).m_rhs; }
level const & imax_lhs(level const & l) { lean_assert(is_imax(l)); return to_max_core(l).m_lhs; }
level const & imax_rhs(level const & l) { lean_assert(is_imax(l)); return to_max_core(l).m_rhs; }
struct level_param_core : public level_cell {
name m_id;
level_param_core(bool is_param, name const & id):
level_cell(is_param ? level_kind::Param : level_kind::Meta, hash(id.hash(), is_param ? 11u : 13u)),
m_id(id) {}
};
static bool is_param_core(level const & l) { return is_param(l) || is_meta(l); }
static level_param_core const & to_param_core(level const & l) {
lean_assert(is_param_core(l));
return static_cast<level_param_core const &>(to_cell(l));
}
name const & param_id(level const & l) { lean_assert(is_param(l)); return to_param_core(l).m_id; }
name const & meta_id(level const & l) { lean_assert(is_meta(l)); return to_param_core(l).m_id; }
void level_cell::dealloc() {
switch (m_kind) {
case level_kind::Succ:
delete static_cast<level_succ*>(this);
break;
case level_kind::Max: case level_kind::IMax:
delete static_cast<level_max_core*>(this);
break;
case level_kind::Param: case level_kind::Meta:
delete static_cast<level_param_core*>(this);
break;
case level_kind::Zero:
delete this;
break;
}
}
unsigned get_depth(level const & l) {
switch (kind(l)) {
case level_kind::Zero: case level_kind::Param: case level_kind::Meta:
return 1;
case level_kind::Succ: case level_kind::Max: case level_kind::IMax:
return to_composite(l).m_depth;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
bool has_param(level const & l) {
switch (kind(l)) {
case level_kind::Zero: case level_kind::Meta:
return false;
case level_kind::Param:
return true;
case level_kind::Succ: case level_kind::Max: case level_kind::IMax:
return to_composite(l).m_has_param;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
bool has_meta(level const & l) {
switch (kind(l)) {
case level_kind::Zero: case level_kind::Param:
return false;
case level_kind::Meta:
return true;
case level_kind::Succ: case level_kind::Max: case level_kind::IMax:
return to_composite(l).m_has_meta;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
bool is_explicit(level const & l) {
switch (kind(l)) {
case level_kind::Zero:
return true;
case level_kind::Param: case level_kind::Meta: case level_kind::Max: case level_kind::IMax:
return false;
case level_kind::Succ:
return to_level_succ(l).m_explicit;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
level mk_succ(level const & l) {
return level(new level_succ(l));
}
level mk_max(level const & l1, level const & l2) {
if (is_explicit(l1) && is_explicit(l2))
return get_depth(l1) >= get_depth(l2) ? l1 : l2;
else if (l1 == l2)
return l1;
else if (is_zero(l1))
return l2;
else if (is_zero(l2))
return l1;
else
return level(new level_max_core(false, l1, l2));
}
level mk_imax(level const & l1, level const & l2) {
if (is_not_zero(l2))
return mk_max(l1, l2);
else if (is_zero(l2))
return l2;
else if (l1 == l2)
return l1;
else
return level(new level_max_core(true, l1, l2));
}
level mk_param_univ(name const & n) {
return level(new level_param_core(true, n));
}
level mk_meta_univ(name const & n) {
return level(new level_param_core(false, n));
}
static level g_zero(new level_cell(level_kind::Zero, 7u));
static level g_one(mk_succ(g_zero));
level const & mk_level_zero() { return g_zero; }
level const & mk_level_one() { return g_one; }
level::level():level(g_zero) {}
level::level(level_cell * ptr):m_ptr(ptr) { lean_assert(m_ptr->get_rc() == 1); }
level::level(level const & s):m_ptr(s.m_ptr) { if (m_ptr) m_ptr->inc_ref(); }
level::level(level && s):m_ptr(s.m_ptr) { s.m_ptr = nullptr; }
level::~level() { if (m_ptr) m_ptr->dec_ref(); }
level & level::operator=(level const & l) { LEAN_COPY_REF(l); }
level & level::operator=(level&& l) { LEAN_MOVE_REF(l); }
level_kind level::kind() const { return m_ptr->m_kind; }
unsigned level::hash() const { return m_ptr->m_hash; }
bool operator==(level const & l1, level const & l2) {
if (kind(l1) != kind(l2)) return false;
if (hash(l1) != hash(l2)) return false;
if (is_eqp(l1, l2)) return true;
switch (kind(l1)) {
case level_kind::Zero:
return true;
case level_kind::Param: case level_kind::Meta:
return to_param_core(l1).m_id == to_param_core(l2).m_id;
case level_kind::Max: case level_kind::IMax: case level_kind::Succ:
if (to_composite(l1).m_depth != to_composite(l2).m_depth)
return false;
break;
}
switch (kind(l1)) {
case level_kind::Zero: case level_kind::Param: case level_kind::Meta:
lean_unreachable(); // LCOV_EXCL_LINE
case level_kind::Max: case level_kind::IMax:
return
to_max_core(l1).m_lhs == to_max_core(l2).m_lhs &&
to_max_core(l1).m_rhs == to_max_core(l2).m_rhs;
case level_kind::Succ:
if (is_explicit(l1) != is_explicit(l2)) {
return false;
} else if (is_explicit(l1)) {
lean_assert(get_depth(l1) == get_depth(l2));
// the depths are equal, then l1 and l2 must be the same universe
return true;
} else {
return succ_of(l1) == succ_of(l2);
}
}
lean_unreachable(); // LCOV_EXCL_LINE
}
bool is_not_zero(level const & l) {
switch (kind(l)) {
case level_kind::Zero: case level_kind::Param: case level_kind::Meta:
return false;
case level_kind::Succ:
return true;
case level_kind::Max:
return is_not_zero(max_lhs(l)) || is_not_zero(max_rhs(l));
case level_kind::IMax:
return is_not_zero(imax_rhs(l));
}
lean_unreachable(); // LCOV_EXCL_LINE
}
// Monotonic total order on universe level terms.
bool is_lt(level const & a, level const & b) {
if (is_eqp(a, b)) return false;
unsigned da = get_depth(a);
unsigned db = get_depth(b);
if (da < db) return true;
if (da > db) return false;
if (kind(a) != kind(b)) return kind(a) < kind(b);
if (hash(a) < hash(b)) return true;
if (hash(a) > hash(b)) return false;
if (a == b) return false;
switch (kind(a)) {
case level_kind::Zero:
return false;
case level_kind::Param: case level_kind::Meta:
return to_param_core(a).m_id < to_param_core(b).m_id;
case level_kind::Max: case level_kind::IMax:
if (to_max_core(a).m_lhs != to_max_core(b).m_lhs)
return is_lt(to_max_core(a).m_lhs, to_max_core(b).m_lhs);
else
return is_lt(to_max_core(a).m_rhs, to_max_core(b).m_rhs);
case level_kind::Succ:
return is_lt(succ_of(a), succ_of(b));
}
lean_unreachable(); // LCOV_EXCL_LINE
}
class level_serializer : public object_serializer<level, level::ptr_hash, level::ptr_eq> {
typedef object_serializer<level, level::ptr_hash, level::ptr_eq> super;
public:
void write(level const & l) {
super::write(l, [&]() {
serializer & s = get_owner();
auto k = kind(l);
s << static_cast<char>(k);
switch (k) {
case level_kind::Zero:
break;
case level_kind::Param: case level_kind::Meta:
s << to_param_core(l).m_id;
break;
case level_kind::Max: case level_kind::IMax:
write(to_max_core(l).m_lhs);
write(to_max_core(l).m_rhs);
break;
case level_kind::Succ:
write(succ_of(l));
break;
}
});
}
};
class level_deserializer : public object_deserializer<level> {
typedef object_deserializer<level> super;
public:
level read() {
return super::read([&]() -> level {
deserializer & d = get_owner();
auto k = static_cast<level_kind>(d.read_char());
switch (k) {
case level_kind::Zero:
return mk_level_zero();
case level_kind::Param:
return mk_param_univ(read_name(d));
case level_kind::Meta:
return mk_meta_univ(read_name(d));
case level_kind::Max: {
level lhs = read();
return mk_max(lhs, read());
}
case level_kind::IMax: {
level lhs = read();
return mk_imax(lhs, read());
}
case level_kind::Succ:
return mk_succ(read());
}
throw_corrupted_file();
});
}
};
struct level_sd {
unsigned m_s_extid;
unsigned m_d_extid;
level_sd() {
m_s_extid = serializer::register_extension([](){
return std::unique_ptr<serializer::extension>(new level_serializer());
});
m_d_extid = deserializer::register_extension([](){
return std::unique_ptr<deserializer::extension>(new level_deserializer());
});
}
};
static level_sd g_level_sd;
serializer & operator<<(serializer & s, level const & n) {
s.get_extension<level_serializer>(g_level_sd.m_s_extid).write(n);
return s;
}
level read_level(deserializer & d) {
return d.get_extension<level_deserializer>(g_level_sd.m_d_extid).read();
}
serializer & operator<<(serializer & s, levels const & ls) {
return write_list<level>(s, ls);
}
levels read_levels(deserializer & d) {
return read_list<level>(d, read_level);
}
serializer & operator<<(serializer & s, level_cnstr const & c) {
s << c.first << c.second;
return s;
}
level_cnstr read_level_cnstr(deserializer & d) {
level lhs = read_level(d);
level rhs = read_level(d);
return level_cnstr(lhs, rhs);
}
serializer & operator<<(serializer & s, level_cnstrs const & cs) {
return write_list<level_cnstr>(s, cs);
}
level_cnstrs read_level_cnstrs(deserializer & d) {
return read_list<level_cnstr>(d, read_level_cnstr);
}
bool has_meta(levels const & ls) {
for (auto const & l : ls) {
if (has_meta(l))
return true;
}
return false;
}
bool has_param(levels const & ls) {
for (auto const & l : ls) {
if (has_param(l))
return true;
}
return false;
}
bool has_param(level_cnstr const & c) {
return has_param(c.first) || has_param(c.second);
}
bool has_param(level_cnstrs const & cs) {
for (auto const & c : cs) {
if (has_param(c))
return true;
}
return false;
}
bool has_meta(level_cnstr const & c) {
return has_meta(c.first) || has_meta(c.second);
}
bool has_meta(level_cnstrs const & cs) {
for (auto const & c : cs) {
if (has_meta(c))
return true;
}
return false;
}
static optional<name> get_undef_param(level const & l, param_names const & ps) {
if (!has_meta(l))
return optional<name>();
switch (l.kind()) {
case level_kind::Succ:
return get_undef_param(succ_of(l), ps);
case level_kind::Max: case level_kind::IMax:
if (auto it = get_undef_param(to_max_core(l).m_lhs, ps))
return it;
else
return get_undef_param(to_max_core(l).m_rhs, ps);
case level_kind::Param:
if (std::find(ps.begin(), ps.end(), param_id(l)) == ps.end())
return optional<name>(param_id(l));
else
return optional<name>();
case level_kind::Zero: case level_kind::Meta:
lean_unreachable(); // LCOV_EXCL_LINE
}
lean_unreachable(); // LCOV_EXCL_LINE
}
optional<name> get_undef_param(level_cnstrs const & cs, param_names const & ps) {
for (auto const & c : cs) {
if (auto it = get_undef_param(c.first, ps))
return it;
if (auto it = get_undef_param(c.second, ps))
return it;
}
return optional<name>();
}
level update_succ(level const & l, level const & new_arg) {
if (is_eqp(succ_of(l), new_arg))
return l;
else
return mk_succ(new_arg);
}
level update_max(level const & l, level const & new_lhs, level const & new_rhs) {
if (is_eqp(to_max_core(l).m_lhs, new_lhs) && is_eqp(to_max_core(l).m_rhs, new_rhs))
return l;
else if (is_max(l))
return mk_max(new_lhs, new_rhs);
else
return mk_imax(new_lhs, new_rhs);
}
level replace_level_fn::apply(level const & l) {
optional<level> r = m_f(l);
if (r)
return *r;
switch (l.kind()) {
case level_kind::Succ:
return update_succ(l, apply(succ_of(l)));
case level_kind::Max: case level_kind::IMax:
return update_max(l, apply(to_max_core(l).m_lhs), apply(to_max_core(l).m_rhs));
case level_kind::Zero: case level_kind::Param: case level_kind::Meta:
return l;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
level instantiate(level const & l, param_names const & ps, levels const & ls) {
lean_assert(length(ps) == length(ls));
return replace(l, [=](level const & l) {
if (!has_param(l)) {
return some_level(l);
} else if (is_param(l)) {
name const & id = param_id(l);
list<name> const *it1 = &ps;
list<level> const * it2 = &ls;
while (!is_nil(*it1)) {
if (head(*it1) == id)
return some_level(head(*it2));
it1 = &tail(*it1);
it2 = &tail(*it2);
}
return some_level(l);
} else {
return none_level();
}
});
}
static void print(std::ostream & out, level l);
static void print_child(std::ostream & out, level const & l) {
if (is_explicit(l) || is_param(l) || is_meta(l)) {
print(out, l);
} else {
out << "(";
print(out, l);
out << ")";
}
}
static void print(std::ostream & out, level l) {
if (is_explicit(l)) {
lean_assert(get_depth(l) > 0);
out << get_depth(l) - 1;
} else {
switch (kind(l)) {
case level_kind::Zero:
lean_unreachable(); // LCOV_EXCL_LINE
case level_kind::Param:
out << param_id(l); break;
case level_kind::Meta:
out << "?" << meta_id(l); break;
case level_kind::Succ:
out << "succ "; print_child(out, succ_of(l)); break;
case level_kind::Max: case level_kind::IMax:
if (is_max(l))
out << "max ";
else
out << "imax ";
print_child(out, max_lhs(l));
// max and imax are right associative
while (kind(max_rhs(l)) == kind(l)) {
l = max_rhs(l);
out << " ";
print_child(out, max_lhs(l));
}
out << " ";
print_child(out, max_rhs(l));
break;
}
}
}
std::ostream & operator<<(std::ostream & out, level const & l) {
print(out, l);
return out;
}
format pp(level l, bool unicode, unsigned indent);
static format pp_child(level const & l, bool unicode, unsigned indent) {
if (is_explicit(l) || is_param(l) || is_meta(l)) {
return pp(l, unicode, indent);
} else {
return paren(pp(l, unicode, indent));
}
}
format pp(level l, bool unicode, unsigned indent) {
if (is_explicit(l)) {
lean_assert(get_depth(l) > 0);
return format(get_depth(l) - 1);
} else {
switch (kind(l)) {
case level_kind::Zero:
lean_unreachable(); // LCOV_EXCL_LINE
case level_kind::Param:
return format(param_id(l));
case level_kind::Meta:
return format{format("?"), format(meta_id(l))};
case level_kind::Succ:
return group(compose(format("succ"), nest(indent, compose(line(), pp_child(succ_of(l), unicode, indent)))));
case level_kind::Max: case level_kind::IMax: {
format r = format(is_max(l) ? "max" : "imax");
r += nest(indent, compose(line(), pp_child(max_lhs(l), unicode, indent)));
// max and imax are right associative
while (kind(max_rhs(l)) == kind(l)) {
l = max_rhs(l);
r += nest(indent, compose(line(), pp_child(max_lhs(l), unicode, indent)));
}
r += nest(indent, compose(line(), pp_child(max_rhs(l), unicode, indent)));
return group(r);
}}
lean_unreachable(); // LCOV_EXCL_LINE
}
}
format pp(level const & l, options const & opts) {
return pp(l, get_pp_unicode(opts), get_pp_indent(opts));
}
bool is_trivial(level const & lhs, level const & rhs) {
check_system("level constraints");
if (is_zero(lhs) || lhs == rhs) {
// 0 <= l
// l <= l
return true;
} else if (is_succ(lhs) && is_succ(rhs)) {
// is_trivial(l <= r) implies is_trivial(succ l <= succ r)
return is_trivial(succ_of(lhs), succ_of(rhs));
} else if (is_succ(rhs)) {
// is_trivial(l <= r) implies is_trivial(l <= succ^k r)
lean_assert(!is_succ(lhs));
level it = succ_of(rhs);
while (is_succ(it))
it = succ_of(it);
return is_trivial(lhs, it);
} else if (is_max(rhs)) {
// is_trivial(l <= l1) implies is_trivial(l <= max(l1, l2))
// is_trivial(l <= l2) implies is_trivial(l <= max(l1, l2))
return is_trivial(lhs, max_lhs(rhs)) || is_trivial(lhs, max_rhs(rhs));
} else if (is_imax(rhs)) {
// is_trivial(l <= l2) implies is_trivial(l <= imax(l1, l2))
return is_trivial(lhs, imax_rhs(rhs));
} else {
return false;
}
}
}
void print(lean::level const & l) { std::cout << l << std::endl; }