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refactor(library/tactic): simplify tactic framework, add orelse and try_for combinators/tacticals

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Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-11-21 18:39:33 -08:00
parent a776c8b158
commit 9fd594533d
6 changed files with 167 additions and 151 deletions
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3
src/library/tactic/proof_builder.h
View file

@ -22,6 +22,7 @@ class proof_builder_cell {
void dealloc() { delete this; }
MK_LEAN_RC();
public:
proof_builder_cell():m_rc(0) {}
virtual ~proof_builder_cell() {}
virtual expr operator()(proof_map const & p, environment const & env, assignment const & a) const = 0;
};
@ -46,7 +47,7 @@ template<typename F>
class simple_proof_builder : public proof_builder_cell {
F m_f;
public:
simple_proof_builder(F && f):m_f(std::forward<F>(f)) {}
simple_proof_builder(F && f):m_f(f) {}
virtual expr operator()(proof_map const & p, environment const & env, assignment const & a) const { return m_f(p, env, a); }
};

2
src/library/tactic/proof_state.cpp
View file

@ -38,7 +38,7 @@ proof_state to_proof_state(environment const & env, context const & ctx, expr co
[=](proof_map const & m, environment const &, assignment const &) -> expr {
expr p = find(m, g_main);
if (!p)
throw tactic_exception(sstream() << "failed to find proof for '" << g_main << "' goal");
throw exception(sstream() << "failed to find proof for '" << g_main << "' goal");
return fn(p);
});
return proof_state(goals(mk_pair(g_main, g)), metavar_env(), p);

164
src/library/tactic/tactic.cpp
View file

@ -5,41 +5,13 @@ Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <utility>
#include <chrono>
#include "util/interrupt.h"
#include "util/lazy_list_fn.h"
#include "library/tactic/tactic_exception.h"
#include "library/tactic/tactic.h"
namespace lean {
tactic_result::~tactic_result() {
}
void tactic_result::interrupt() {
m_interrupted = true;
}
void tactic_result::request_interrupt() {
{
std::lock_guard<std::mutex> lock(m_mutex);
interrupt();
}
::lean::request_interrupt();
}
proof_state_ref tactic_result::next(environment const & env, io_state const & s) {
try {
return next_core(env, s);
} catch (interrupted &) {
if (m_interrupted) {
// promote to tactic_exception if tactic is marked as interrupted
throw tactic_exception("interrupted");
} else {
// if tactic was not interrupted, then continue propagating interrupted exception
throw;
}
}
}
tactic_cell::~tactic_cell() {
}
tactic & tactic::operator=(tactic const & s) {
LEAN_COPY_REF(tactic, s);
}
@ -49,15 +21,13 @@ tactic & tactic::operator=(tactic && s) {
}
expr tactic::solve(environment const & env, io_state const & io, proof_state const & s) {
tactic_result_ref r = operator()(s);
proof_state_ref final = r->next(env, io);
if (!final)
throw tactic_exception("tactic did not produce any result");
if (!empty(final->get_goals()))
throw tactic_exception("tactic did not solve all goals");
assignment a(final->get_menv());
proof_state_seq r = operator()(env, io, s);
if (!r)
throw exception("tactic failed to solve input");
proof_state final = head(r);
assignment a(final.get_menv());
proof_map m;
return final->get_proof_builder()(m, env, a);
return final.get_proof_builder()(m, env, a);
}
expr tactic::solve(environment const & env, io_state const & io, context const & ctx, expr const & t) {
@ -65,20 +35,29 @@ expr tactic::solve(environment const & env, io_state const & io, context const &
return solve(env, io, s);
}
tactic id_tactic() { return mk_tactic([](environment const &, io_state const &, proof_state const & s) -> proof_state { return s; }); }
tactic id_tactic() {
return mk_tactic([](environment const &, io_state const &, proof_state const & s) -> proof_state_seq {
return proof_state_seq(s);
});
}
tactic fail_tactic() { return mk_tactic([](environment const &, io_state const &, proof_state const &) -> proof_state { throw tactic_exception("failed"); }); }
tactic fail_tactic() {
return mk_tactic([](environment const &, io_state const &, proof_state const &) -> proof_state_seq {
return proof_state_seq();
});
}
tactic now_tactic() {
return mk_tactic([](environment const &, io_state const &, proof_state const & s) -> proof_state {
return mk_tactic([](environment const &, io_state const &, proof_state const & s) -> proof_state_seq {
if (!empty(s.get_goals()))
throw tactic_exception("nowtac failed");
return s;
return proof_state_seq();
else
return proof_state_seq(s);
});
}
tactic assumption_tactic() {
return mk_tactic([](environment const &, io_state const &, proof_state const & s) -> proof_state {
return mk_tactic([](environment const &, io_state const &, proof_state const & s) -> proof_state_seq {
list<std::pair<name, expr>> proofs;
goals new_goals = map_goals(s, [&](name const & ng, goal const & g) -> goal {
expr const & c = g.get_conclusion();
@ -105,54 +84,69 @@ tactic assumption_tactic() {
}
return p(new_m, env, a);
});
return proof_state(s, new_goals, new_p);
return proof_state_seq(proof_state(s, new_goals, new_p));
});
}
class then_tactic : public tactic_cell {
tactic m_t1;
tactic m_t2;
public:
then_tactic(tactic const & t1, tactic const & t2):m_t1(t1), m_t2(t2) {}
tactic then(tactic t1, tactic t2) {
return mk_tactic([=](environment const & env, io_state const & io, proof_state const & s1) -> proof_state_seq {
tactic _t1(t1);
return map_append(_t1(env, io, s1), [=](proof_state const & s2) {
check_interrupted();
tactic _t2(t2);
return _t2(env, io, s2);
});
});
}
class result : public tactic_result {
tactic_result_ref m_r1;
proof_state_ref m_s1;
tactic m_t2;
tactic_result_ref m_r2;
protected:
virtual void interrupt() {
tactic_result::interrupt();
propagate_interrupt(m_r1);
propagate_interrupt(m_r2);
tactic orelse(tactic t1, tactic t2) {
return mk_tactic([=](environment const & env, io_state const & io, proof_state const & s) -> proof_state_seq {
tactic _t1(t1);
proof_state_seq r = _t1(env, io, s);
if (r) {
return r;
} else {
check_interrupted();
tactic _t2(t2);
return _t2(env, io, s);
}
});
}
public:
result(tactic_result_ref && r1, tactic const & t2):m_r1(std::move(r1)), m_t2(t2) {}
virtual proof_state_ref next_core(environment const & env, io_state const & s) {
if (m_r2) {
proof_state_ref s2 = m_r2->next(env, s);
if (s2)
return s2;
m_r2.release();
m_s1.release();
tactic try_for(tactic t, unsigned ms, unsigned check_ms) {
if (check_ms == 0)
check_ms = 1;
return mk_tactic([=](environment const & env, io_state const & io, proof_state const & s) -> proof_state_seq {
tactic _t(t);
proof_state_seq r;
std::atomic<bool> done(false);
interruptible_thread th([&]() {
try {
r = _t(env, io, s);
} catch (...) {
r = proof_state_seq();
}
lean_assert(!m_r2);
lean_assert(!m_s1);
proof_state_ref new_s1(m_r1->next(env, s));
if (!new_s1)
return proof_state_ref(); // done, m_r1 has no more solutions
m_s1.swap(new_s1);
tactic_result_ref r2 = m_t2(proof_state(*m_s1));
exclusive_update([&]() { m_r2.swap(r2); }); // must protect because interrupt() may be invoked from different thread
return m_r2->next(env, s);
done = true;
});
try {
auto start = std::chrono::steady_clock::now();
std::chrono::milliseconds d(ms);
std::chrono::milliseconds one(1);
while (!done) {
auto curr = std::chrono::steady_clock::now();
if (std::chrono::duration_cast<std::chrono::milliseconds>(curr - start) > d)
break;
check_interrupted();
std::this_thread::sleep_for(one);
}
};
virtual tactic_result_ref operator()(proof_state const & s) {
return tactic_result_ref(new result(m_t1(s), m_t2));
th.request_interrupt();
th.join();
return r;
} catch (...) {
th.request_interrupt();
th.join();
throw;
}
});
}
};
tactic then(tactic const & t1, tactic const & t2) { return tactic(new then_tactic(t1, t2)); }
}

63
src/library/tactic/tactic.h
View file

@ -6,41 +6,24 @@ Author: Leonardo de Moura
*/
#pragma once
#include <algorithm>
#include <utility>
#include <memory>
#include <mutex>
#include "util/interrupt.h"
#include "util/lazy_list.h"
#include "library/io_state.h"
#include "library/tactic/proof_state.h"
namespace lean {
typedef std::unique_ptr<proof_state> proof_state_ref;
class tactic_result;
typedef std::unique_ptr<tactic_result> tactic_result_ref;
class tactic_result {
std::mutex m_mutex;
std::atomic<bool> m_interrupted;
protected:
template<typename F>
void exclusive_update(F && f) {
std::lock_guard<std::mutex> lock(m_mutex);
f();
}
virtual void interrupt();
void propagate_interrupt(tactic_result_ref & r) { if (r) r->interrupt(); }
virtual proof_state_ref next_core(environment const & env, io_state const & s) = 0;
public:
tactic_result():m_interrupted(false) {}
void request_interrupt();
proof_state_ref next(environment const & env, io_state const & s);
virtual ~tactic_result();
};
typedef lazy_list<proof_state> proof_state_seq;
class tactic_cell {
void dealloc() { delete this; }
MK_LEAN_RC();
public:
virtual ~tactic_cell();
virtual tactic_result_ref operator()(proof_state const & s) = 0;
tactic_cell():m_rc(0) {}
virtual ~tactic_cell() {}
virtual proof_state_seq operator()(environment const & env, io_state const & io, proof_state const & s) = 0;
};
class tactic {
@ -55,7 +38,7 @@ public:
tactic & operator=(tactic const & s);
tactic & operator=(tactic && s);
tactic_result_ref operator()(proof_state const & s) { return m_ptr->operator()(s); }
proof_state_seq operator()(environment const & env, io_state const & io, proof_state const & s) { return m_ptr->operator()(env, io, s); }
expr solve(environment const & env, io_state const & io, proof_state const & s);
expr solve(environment const & env, io_state const & io, context const & ctx, expr const & t);
@ -66,29 +49,8 @@ class simple_tactic_cell : public tactic_cell {
F m_f;
public:
simple_tactic_cell(F && f):m_f(f) {}
class result : public tactic_result {
simple_tactic_cell * m_cell;
proof_state m_in;
public:
result(simple_tactic_cell * c, proof_state const & in):m_cell(c), m_in(in) {
lean_assert(m_cell);
m_cell->inc_ref();
}
virtual ~result() { if (m_cell) m_cell->dec_ref(); }
virtual proof_state_ref next_core(environment const & env, io_state const & io) {
if (m_cell) {
proof_state_ref r(new proof_state(m_cell->m_f(env, io, m_in)));
m_cell = nullptr;
return std::move(r);
} else {
return proof_state_ref();
}
}
};
virtual tactic_result_ref operator()(proof_state const & s) {
return tactic_result_ref(new result(this, s));
virtual proof_state_seq operator()(environment const & env, io_state const & io, proof_state const & s) {
return m_f(env, io, s);
}
};
@ -99,5 +61,8 @@ tactic id_tactic();
tactic fail_tactic();
tactic now_tactic();
tactic assumption_tactic();
tactic then(tactic const & t1, tactic const & t2);
tactic then(tactic t1, tactic t2);
tactic orelse(tactic t1, tactic t2);
tactic try_for(tactic t, unsigned ms, unsigned check_ms = g_small_sleep);
tactic repeat(tactic t1);
}

13
src/library/tactic/tactic_exception.h
View file

@ -7,12 +7,19 @@ Author: Leonardo de Moura
#pragma once
#include <string>
#include "util/exception.h"
#include "kernel/justification.h"
namespace lean {
/**
\brief Tactic and related components store the reason for
failure in justification objects.
*/
class tactic_exception : public exception {
justification m_justification;
public:
tactic_exception(char const * msg):exception(msg) {}
tactic_exception(std::string const & msg):exception(msg) {}
tactic_exception(sstream const & strm):exception(strm) {}
tactic_exception(justification const & j):m_justification(j) {}
virtual ~tactic_exception() {}
virtual char const * what() const noexcept { return "tactic exception"; }
justification const & get_justification() const { return m_justification; }
};
}

61
src/tests/library/tactic/tactic.cpp
View file

@ -4,7 +4,9 @@ Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <string>
#include "util/test.h"
#include "util/interrupt.h"
#include "kernel/builtin.h"
#include "library/all/all.h"
#include "library/tactic/goal.h"
@ -14,6 +16,38 @@ Author: Leonardo de Moura
#include "library/tactic/tactic_exception.h"
using namespace lean;
tactic loop_tactic() {
return mk_tactic([=](environment const &, io_state const &, proof_state const &) -> proof_state_seq {
while (true) {
check_interrupted();
}
return proof_state_seq();
});
}
tactic msg_tactic(std::string msg) {
return mk_tactic([=](environment const &, io_state const &, proof_state const & s) -> proof_state_seq {
std::cout << msg << "\n";
return proof_state_seq(s);
});
}
tactic set_tactic(std::atomic<bool> * flag) {
return mk_tactic([=](environment const &, io_state const &, proof_state const & s) -> proof_state_seq {
*flag = true;
return proof_state_seq(s);
});
}
static void check_failure(tactic t, environment const & env, io_state const & io, context const & ctx, expr const & ty) {
try {
t.solve(env, io, ctx, ty);
lean_unreachable();
} catch (exception & ex) {
std::cout << "expected error: " << ex.what() << "\n";
}
}
static void tst1() {
environment env;
io_state io(options(), mk_simple_formatter());
@ -30,12 +64,27 @@ static void tst1() {
tactic t = then(assumption_tactic(), now_tactic());
std::cout << "proof 1: " << t.solve(env, io, s) << "\n";
std::cout << "proof 2: " << t.solve(env, io, ctx, q) << "\n";
try {
now_tactic().solve(env, io, ctx, q);
lean_unreachable();
} catch (tactic_exception & ex) {
std::cout << "expected error: " << ex.what() << "\n";
}
check_failure(now_tactic(), env, io, ctx, q);
std::cout << "proof 2: " << orelse(fail_tactic(), t).solve(env, io, ctx, q) << "\n";
#ifndef __APPLE__
check_failure(try_for(loop_tactic(), 100), env, io, ctx, q);
std::cout << "proof 1: " << try_for(t, 10000).solve(env, io, s) << "\n";
check_failure(try_for(orelse(try_for(loop_tactic(), 10000),
msg_tactic(std::string("hello world"))),
100),
env, io, ctx, q);
std::atomic<bool> flag1(false);
check_failure(try_for(orelse(try_for(loop_tactic(), 10000),
set_tactic(&flag1)),
100),
env, io, ctx, q);
lean_assert(!flag1);
check_failure(orelse(try_for(try_for(loop_tactic(), 10000), 100),
set_tactic(&flag1)),
env, io, ctx, q);
lean_assert(flag1);
#endif
std::cout << "done\n";
}
int main() {