lean4-htt/src/frontends/lean/structure_instance.cpp

106 lines
4.4 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 <string>
#include "util/sstream.h"
#include "library/kernel_serializer.h"
#include "frontends/lean/parser.h"
#include "frontends/lean/tokens.h"
namespace lean {
static name * g_structure_instance_name = nullptr;
static std::string * g_structure_instance_opcode = nullptr;
[[ noreturn ]] static void throw_se_ex() { throw exception("unexpected occurrence of 'structure instance' expression"); }
/*
We encode a 'structure instance' expression using a macro.
This is a trick to avoid creating a new kind of expression.
'Structure instance' expressions are temporary objects used by the elaborator.
Example: Given
structure point (A B : Type) := (x : A) (y : B)
the structure instance
{ point, x := 10, y := 20 }
is compiled into
point.mk 10 20
*/
class structure_instance_macro_cell : public macro_definition_cell {
name m_struct;
list<name> m_fields;
public:
structure_instance_macro_cell(name const & s, list<name> const & fs):
m_struct(s), m_fields(fs) {}
virtual name get_name() const { return *g_structure_instance_name; }
virtual expr check_type(expr const &, abstract_type_context &, bool) const { throw_se_ex(); }
virtual optional<expr> expand(expr const &, abstract_type_context &) const { throw_se_ex(); }
virtual void write(serializer & s) const {
s << *g_structure_instance_opcode << m_struct;
write_list(s, m_fields);
}
name const & get_struct() const { return m_struct; }
list<name> const & get_field_names() const { return m_fields; }
};
static expr mk_structure_instance_core(name const & s, list<name> const & fs, unsigned num, expr const * args) {
lean_assert(num == length(fs) || num == length(fs) + 1);
macro_definition def(new structure_instance_macro_cell(s, fs));
return mk_macro(def, num, args);
}
expr mk_structure_instance(name const & s, buffer<name> const & fns, buffer<expr> const & fvs) {
lean_assert(fns.size() == fvs.size());
return mk_structure_instance_core(s, to_list(fns), fvs.size(), fvs.data());
}
expr mk_structure_instance(expr const & src, buffer<name> const & fns, buffer<expr> const & fvs) {
buffer<expr> aux;
aux.append(fvs);
aux.push_back(src);
return mk_structure_instance_core(name(), to_list(fns), aux.size(), aux.data());
}
bool is_structure_instance(expr const & e) {
return is_macro(e) && macro_def(e).get_name() == *g_structure_instance_name;
}
void get_structure_instance_info(expr const & e,
name & struct_name,
optional<expr> & source,
buffer<name> & field_names,
buffer<expr> & field_values) {
lean_assert(is_structure_instance(e));
struct_name = static_cast<structure_instance_macro_cell const*>(macro_def(e).raw())->get_struct();
list<name> const & fns = static_cast<structure_instance_macro_cell const*>(macro_def(e).raw())->get_field_names();
to_buffer(fns, field_names);
unsigned num_fields = field_names.size();
lean_assert(macro_num_args(e) == num_fields || macro_num_args(e) == num_fields+1);
if (num_fields < macro_num_args(e))
source = macro_arg(e, num_fields);
for (unsigned i = 0; i < num_fields; i++)
field_values.push_back(macro_arg(e, i));
}
void initialize_structure_instance() {
g_structure_instance_name = new name("structure instance");
g_structure_instance_opcode = new std::string("STI");
register_macro_deserializer(*g_structure_instance_opcode,
[](deserializer & d, unsigned num, expr const * args) {
list<name> fns;
name s;
d >> s;
fns = read_list<name>(d);
unsigned len = length(fns);
if (num != len + 1 && num != len)
throw corrupted_stream_exception();
return mk_structure_instance_core(s, fns, num, args);
});
}
void finalize_structure_instance() {
delete g_structure_instance_opcode;
delete g_structure_instance_name;
}
}