lean4-htt/src/library/metavar_context.cpp

233 lines
7.1 KiB
C++

/*
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "util/fresh_name.h"
#include "kernel/for_each_fn.h"
#include "library/metavar_util.h"
#include "library/metavar_context.h"
namespace lean {
static name * g_meta_prefix;
static expr * g_dummy_type;
name mk_meta_decl_name() {
return mk_tagged_fresh_name(*g_meta_prefix);
}
expr mk_meta_ref(name const & n) {
return mk_metavar(n, *g_dummy_type);
}
bool is_metavar_decl_ref(level const & u) {
return is_meta(u) && is_tagged_by(meta_id(u), *g_meta_prefix);
}
bool is_metavar_decl_ref(expr const & e) {
return is_metavar(e) && mlocal_type(e) == *g_dummy_type;
}
name get_metavar_decl_ref_suffix(level const & u) {
lean_assert(is_metavar_decl_ref(u));
return *get_tagged_name_suffix(meta_id(u), *g_meta_prefix);
}
name get_metavar_decl_ref_suffix(expr const & e) {
lean_assert(is_metavar_decl_ref(e));
if (auto r = get_tagged_name_suffix(mlocal_name(e), *g_meta_prefix))
return *r;
else
return mlocal_name(e);
}
level metavar_context::mk_univ_metavar_decl() {
return mk_meta_univ(mk_meta_decl_name());
}
expr metavar_context::mk_metavar_decl(local_context const & ctx, expr const & type) {
name n = mk_meta_decl_name();
m_decls.insert(n, metavar_decl(ctx, head_beta_reduce(type)));
return mk_meta_ref(n);
}
optional<metavar_decl> metavar_context::find_metavar_decl(expr const & e) const {
lean_assert(is_metavar_decl_ref(e));
if (auto r = m_decls.find(mlocal_name(e)))
return optional<metavar_decl>(*r);
else
return optional<metavar_decl>();
}
metavar_decl const & metavar_context::get_metavar_decl(expr const & e) const {
if (auto r = m_decls.find(mlocal_name(e)))
return *r;
else
throw exception("unknown metavariable");
}
optional<local_decl> metavar_context::find_local_decl(expr const & mvar, name const & n) const {
auto mdecl = find_metavar_decl(mvar);
if (!mdecl) return optional<local_decl>();
return mdecl->get_context().find_local_decl(n);
}
local_decl metavar_context::get_local_decl(expr const & mvar, name const & n) const {
return get_metavar_decl(mvar).get_context().get_local_decl(n);
}
expr metavar_context::get_local(expr const & mvar, name const & n) const {
return get_local_decl(mvar, n).mk_ref();
}
void metavar_context::assign(level const & u, level const & l) {
m_uassignment.insert(meta_id(u), l);
}
void metavar_context::assign(expr const & e, expr const & v) {
m_eassignment.insert(mlocal_name(e), v);
}
optional<level> metavar_context::get_assignment(level const & l) const {
lean_assert(is_metavar_decl_ref(l));
if (auto v = m_uassignment.find(meta_id(l)))
return some_level(*v);
else
return none_level();
}
optional<expr> metavar_context::get_assignment(expr const & e) const {
lean_assert(is_metavar_decl_ref(e));
if (auto v = m_eassignment.find(mlocal_name(e)))
return some_expr(*v);
else
return none_expr();
}
struct metavar_context::interface_impl {
metavar_context & m_ctx;
interface_impl(metavar_context const & ctx):m_ctx(const_cast<metavar_context&>(ctx)) {}
static bool is_mvar_core(level const & l) { return is_metavar_decl_ref(l); }
bool is_assigned(level const & l) const { return m_ctx.is_assigned(l); }
optional<level> get_assignment(level const & l) const { return m_ctx.get_assignment(l); }
void assign(level const & u, level const & v) { m_ctx.assign(u, v); }
static bool is_mvar_core(expr const & e) { return is_metavar_decl_ref(e); }
bool is_assigned(expr const & e) const { return m_ctx.is_assigned(e); }
optional<expr> get_assignment(expr const & e) const { return m_ctx.get_assignment(e); }
void assign(expr const & m, expr const & v) { m_ctx.assign(m, v); }
bool in_tmp_mode() const { return false; }
};
bool metavar_context::has_assigned(level const & l) const {
return ::lean::has_assigned(interface_impl(*this), l);
}
bool metavar_context::has_assigned(expr const & e) const {
return ::lean::has_assigned(interface_impl(*this), e);
}
level metavar_context::instantiate_mvars(level const & l) {
interface_impl impl(*this);
return ::lean::instantiate_mvars(impl, l);
}
expr metavar_context::instantiate_mvars(expr const & e, bool postpone_push_delayed) {
interface_impl impl(*this);
return ::lean::instantiate_mvars(impl, e, postpone_push_delayed);
}
void metavar_context::instantiate_mvars_at_type_of(expr const & m) {
metavar_decl d = get_metavar_decl(m);
expr type = d.get_type();
expr new_type = instantiate_mvars(type);
if (new_type != type) {
m_decls.insert(mlocal_name(m), metavar_decl(d.get_context(), new_type));
}
}
template<typename C>
static bool well_formed_metavar_occs(expr const & e, C const & ds, metavar_context const & ctx) {
bool ok = true;
for_each(e, [&](expr const & e, unsigned) {
if (!ok) return false;
if (!has_expr_metavar(e)) return false;
if (is_metavar_decl_ref(e)) {
if (auto d = ctx.find_metavar_decl(e)) {
if (!d->get_context().is_subset_of(ds)) {
/* invalid metavariable context */
ok = false;
return false;
}
} else {
/* undefined metavariable */
ok = false;
return false;
}
}
return true;
});
return ok;
}
bool metavar_context::well_formed(local_context const & ctx) const {
bool ok = true;
name_set visited;
ctx.for_each([&](local_decl const & d) {
if (!well_formed_metavar_occs(d.get_type(), visited, *this)) {
ok = false;
lean_unreachable();
}
if (auto v = d.get_value()) {
if (!well_formed_metavar_occs(*v, visited, *this)) {
ok = false;
lean_unreachable();
}
}
visited.insert(d.get_name());
});
return ok;
}
bool metavar_context::well_formed(local_context const & ctx, expr const & e) const {
return well_formed_metavar_occs(e, ctx, *this);
}
bool well_formed(local_context const & lctx, metavar_context const & mctx) {
if (!lctx.well_formed()) {
lean_unreachable();
return false;
}
if (!mctx.well_formed(lctx)) {
lean_unreachable();
return false;
}
return true;
}
bool well_formed(local_context const & lctx, metavar_context const & mctx, expr const & e) {
if (!lctx.well_formed(e)) {
lean_unreachable();
return false;
}
if (!mctx.well_formed(lctx, e)) {
lean_unreachable();
return false;
}
return true;
}
void initialize_metavar_context() {
g_meta_prefix = new name(name::mk_internal_unique_name());
g_dummy_type = new expr(mk_constant(name::mk_internal_unique_name()));
}
void finalize_metavar_context() {
delete g_meta_prefix;
delete g_dummy_type;
}
}