lean2/src/library/app_builder.cpp

307 lines
12 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 "util/scoped_map.h"
#include "util/name_map.h"
#include "kernel/instantiate.h"
#include "library/match.h"
#include "library/app_builder.h"
#include "library/kernel_bindings.h"
namespace lean {
struct app_builder::imp {
// For each declaration we associate the number of explicit arguments provided to
// it, and which of them are used to infer the implicit arguments.
struct decl_info {
unsigned m_nargs; // total number of explicit arguments
list<unsigned> m_used_idxs; // which ones are used to infer implicit arguments
decl_info(unsigned nargs, list<unsigned> const & used_idxs):
m_nargs(nargs), m_used_idxs(used_idxs) {}
decl_info() {}
};
struct cache_key {
name m_name;
list<expr> m_arg_types;
unsigned m_hash;
cache_key(name const & n, unsigned num_arg_types, expr const * arg_types):
m_name(n), m_arg_types(to_list(arg_types, arg_types + num_arg_types)) {
m_hash = m_name.hash();
for (unsigned i = 0; i < num_arg_types; i++)
m_hash = hash(m_hash, arg_types[i].hash());
}
};
struct cache_key_hash_fn {
unsigned operator()(cache_key const & e) const { return e.m_hash; }
};
struct cache_key_equal_fn {
bool operator()(cache_key const & e1, cache_key const & e2) const {
return
e1.m_name == e2.m_name &&
e1.m_arg_types == e2.m_arg_types;
}
};
// The cache stores a mapping (decl + type of explicit arguments ==> term t).
// If t is closed term, then we obtain the final application by using
// mk_app(t, explicit_args)
// If t contains free variables, then we obtain the final application by using
// instantiate(t, explicit_args)
typedef scoped_map<cache_key, expr, cache_key_hash_fn, cache_key_equal_fn> cache;
type_checker & m_tc;
whnf_match_plugin m_plugin;
name_map<decl_info> m_decl_info;
cache m_cache;
buffer<levels> m_levels;
imp(type_checker & tc):m_tc(tc), m_plugin(tc) {
m_levels.push_back(levels());
}
// Make sure m_levels contains at least nlvls metavariable universe levels
void ensure_levels(unsigned nlvls) {
while (m_levels.size() <= nlvls) {
level new_lvl = mk_idx_metauniv(m_levels.size() - 1);
levels new_lvls = append(m_levels.back(), levels(new_lvl));
m_levels.push_back(new_lvls);
}
}
// We say the given mask is simple if it is of the form (false*, true*).
// That is, a block of false followed by a blocked of true
static bool is_simple_mask(buffer<bool> & explicit_mask) {
bool found_true = false;
for (bool const & b : explicit_mask) {
if (b)
found_true = true;
else if (found_true)
return false;
}
return true;
}
void save_decl_info(declaration const & d, unsigned nargs, buffer<unsigned> const & used_idxs) {
if (!m_decl_info.contains(d.get_name())) {
m_decl_info.insert(d.get_name(), decl_info(nargs, to_list(used_idxs)));
}
}
optional<expr> mk_app_core(declaration const & d, unsigned nargs, expr const * args, bool use_cache) {
unsigned num_univs = d.get_num_univ_params();
ensure_levels(num_univs);
expr type = instantiate_type_univ_params(d, m_levels[num_univs]);
buffer<optional<level>> lsubst;
buffer<optional<expr>> esubst;
lsubst.resize(num_univs, none_level());
constraint_seq cs;
buffer<unsigned> used_idxs;
buffer<expr> used_types;
buffer<bool> explicit_mask;
buffer<expr> domain_types;
unsigned idx = 0;
while (is_pi(type)) {
explicit_mask.push_back(is_explicit(binding_info(type)));
esubst.push_back(none_expr());
domain_types.push_back(binding_domain(type));
// TODO(Leo): perhaps, we should cache the result of this while-loop.
// The result of this computation can be reused in future calls.
expr meta = mk_idx_metavar(idx, binding_domain(type));
idx++;
type = instantiate(binding_body(type), meta);
}
unsigned i = domain_types.size();
unsigned j = nargs;
while (i > 0) {
--i;
if (explicit_mask[i]) {
if (j == 0)
return none_expr();
--j;
expr arg_type = m_tc.infer(args[j], cs);
if (cs)
return none_expr();
bool assigned = false;
if (!match(domain_types[i], arg_type, lsubst, esubst,
nullptr, nullptr, &m_plugin, &assigned))
return none_expr();
if (assigned && use_cache) {
used_idxs.push_back(j);
used_types.push_back(arg_type);
}
esubst[i] = some_expr(args[j]);
} else {
if (!esubst[i])
return none_expr();
expr arg_type = m_tc.infer(*esubst[i], cs);
if (cs)
return none_expr();
if (!match(domain_types[i], arg_type, lsubst, esubst,
nullptr, nullptr, &m_plugin))
return none_expr();
}
}
bool has_unassigned_lvls = std::find(lsubst.begin(), lsubst.end(), none_level()) != lsubst.end();
if (j > 0 || has_unassigned_lvls)
return none_expr();
if (use_cache)
save_decl_info(d, nargs, used_idxs);
buffer<level> r_lvls;
for (optional<level> const & l : lsubst)
r_lvls.push_back(*l);
buffer<expr> r_args;
for (optional<expr> const & o : esubst)
r_args.push_back(*o);
lean_assert(explicit_mask.size() == r_args.size());
if (!use_cache) {
return some_expr(::lean::mk_app(mk_constant(d.get_name(), to_list(r_lvls)), r_args.size(), r_args.data()));
} else if (is_simple_mask(explicit_mask)) {
expr f = ::lean::mk_app(mk_constant(d.get_name(), to_list(r_lvls)), r_args.size() - nargs, r_args.data());
if (use_cache) {
cache_key k(d.get_name(), used_types.size(), used_types.data());
m_cache.insert(k, f);
}
return some_expr(::lean::mk_app(f, nargs, r_args.end() - nargs));
} else {
buffer<expr> imp_args;
buffer<expr> expl_args;
for (unsigned i = 0; i < explicit_mask.size(); i++) {
if (explicit_mask[i]) {
imp_args.push_back(mk_var(expl_args.size()));
expl_args.push_back(r_args[i]);
} else {
imp_args.push_back(r_args[i]);
}
}
expr f = ::lean::mk_app(mk_constant(d.get_name(), to_list(r_lvls)), imp_args.size(), imp_args.data());
if (use_cache) {
cache_key k(d.get_name(), used_types.size(), used_types.data());
m_cache.insert(k, f);
}
return some_expr(instantiate(f, expl_args.size(), expl_args.data()));
}
}
optional<expr> mk_app(declaration const & d, unsigned nargs, expr const * args, bool use_cache) {
if (use_cache) {
if (auto info = m_decl_info.find(d.get_name())) {
if (info->m_nargs != nargs)
return none_expr();
buffer<expr> arg_types;
constraint_seq cs;
for (unsigned idx : info->m_used_idxs) {
lean_assert(idx < nargs);
expr t = m_tc.infer(args[idx], cs);
if (cs)
return none_expr(); // constraint was generated
arg_types.push_back(t);
}
cache_key k(d.get_name(), arg_types.size(), arg_types.data());
auto it = m_cache.find(k);
if (it != m_cache.end()) {
if (closed(it->second))
return some_expr(::lean::mk_app(it->second, nargs, args));
else
return some_expr(instantiate(it->second, nargs, args));
} else {
return mk_app_core(d, nargs, args, use_cache);
}
}
}
return mk_app_core(d, nargs, args, use_cache);
}
void push() {
m_cache.push();
}
void pop() {
m_cache.pop();
}
};
app_builder::app_builder(type_checker & tc):m_ptr(new imp(tc)) {}
app_builder::~app_builder() {}
optional<expr> app_builder::mk_app(declaration const & d, unsigned nargs, expr const * args, bool use_cache) {
return m_ptr->mk_app(d, nargs, args, use_cache);
}
optional<expr> app_builder::mk_app(name const & n, unsigned nargs, expr const * args, bool use_cache) {
declaration const & d = m_ptr->m_tc.env().get(n);
return mk_app(d, nargs, args, use_cache);
}
optional<expr> app_builder::mk_app(name const & n, std::initializer_list<expr> const & args, bool use_cache) {
return mk_app(n, args.size(), args.begin(), use_cache);
}
optional<expr> app_builder::mk_app(name const & n, expr const & a1, bool use_cache) {
return mk_app(n, {a1}, use_cache);
}
optional<expr> app_builder::mk_app(name const & n, expr const & a1, expr const & a2, bool use_cache) {
return mk_app(n, {a1, a2}, use_cache);
}
optional<expr> app_builder::mk_app(name const & n, expr const & a1, expr const & a2, expr const & a3, bool use_cache) {
return mk_app(n, {a1, a2, a3}, use_cache);
}
void app_builder::push() { m_ptr->push(); }
void app_builder::pop() { m_ptr->pop(); }
struct lua_app_builder {
type_checker_ref m_tc;
app_builder m_builder;
lua_app_builder(type_checker_ref const & r):m_tc(r), m_builder(*r.get()) {}
};
typedef std::shared_ptr<lua_app_builder> app_builder_ref;
DECL_UDATA(app_builder_ref)
static int mk_app_builder(lua_State * L) {
return push_app_builder_ref(L, std::make_shared<lua_app_builder>(to_type_checker_ref(L, 1)));
}
static int app_builder_mk_app(lua_State * L) {
int nargs = lua_gettop(L);
buffer<expr> args;
app_builder & b = to_app_builder_ref(L, 1)->m_builder;
bool use_cache = true;
name n = to_name_ext(L, 2);
for (int i = 3; i <= nargs; i++) {
if (i < nargs || is_expr(L, i))
args.push_back(to_expr(L, i));
else
use_cache = lua_toboolean(L, i);
}
return push_optional_expr(L, b.mk_app(n, args.size(), args.data(), use_cache));
}
static int app_builder_push(lua_State * L) {
to_app_builder_ref(L, 1)->m_builder.push();
return 0;
}
static int app_builder_pop(lua_State * L) {
to_app_builder_ref(L, 1)->m_builder.pop();
return 0;
}
static const struct luaL_Reg app_builder_ref_m[] = {
{"__gc", app_builder_ref_gc},
{"mk_app", safe_function<app_builder_mk_app>},
{"push", safe_function<app_builder_push>},
{"pop", safe_function<app_builder_pop>},
{0, 0}
};
void open_app_builder(lua_State * L) {
luaL_newmetatable(L, app_builder_ref_mt);
lua_pushvalue(L, -1);
lua_setfield(L, -2, "__index");
setfuncs(L, app_builder_ref_m, 0);
SET_GLOBAL_FUN(mk_app_builder, "app_builder");
SET_GLOBAL_FUN(app_builder_ref_pred, "is_app_builder");
}
}