#pragma once

#include "ceval.h"
#include "compiler.h"
#include "obj.h"
#include "repl.h"
#include "iter.h"
#include "base64.h"
#include "cffi.h"
#include "linalg.h"
#include "easing.h"
#include "requests.h"
#include "io.h"
#include "_generated.h"
#include "export.h"
#include "vm.h"
#include "re.h"
#include "random.h"

namespace pkpy {

inline CodeObject_ VM::compile(Str source, Str filename, CompileMode mode, bool unknown_global_scope) {
    Compiler compiler(this, source, filename, mode, unknown_global_scope);
    try{
        return compiler.compile();
    }catch(Exception& e){
#if DEBUG_FULL_EXCEPTION
        std::cerr << e.summary() << std::endl;
#endif
        _error(e);
        return nullptr;
    }
}


inline void init_builtins(VM* _vm) {
#define BIND_NUM_ARITH_OPT(name, op)                                                                    \
    _vm->bind##name(_vm->tp_int, [](VM* vm, PyObject* lhs, PyObject* rhs) {                             \
        if(is_int(rhs)){                                                                                \
            return VAR(_CAST(i64, lhs) op _CAST(i64, rhs));                                             \
        }else{                                                                                          \
            return VAR(_CAST(i64, lhs) op vm->num_to_float(rhs));                                       \
        }                                                                                               \
    });                                                                                                 \
    _vm->bind##name(_vm->tp_float, [](VM* vm, PyObject* lhs, PyObject* rhs) {                           \
        return VAR(_CAST(f64, lhs) op vm->num_to_float(rhs));                                           \
    });

    BIND_NUM_ARITH_OPT(__add__, +)
    BIND_NUM_ARITH_OPT(__sub__, -)
    BIND_NUM_ARITH_OPT(__mul__, *)

#undef BIND_NUM_ARITH_OPT

#define BIND_NUM_LOGICAL_OPT(name, op, is_eq)   \
    _vm->bind##name(_vm->tp_int, [](VM* vm, PyObject* lhs, PyObject* rhs) { \
        if(is_int(rhs))     return _CAST(i64, lhs) op _CAST(i64, rhs);      \
        if(is_float(rhs))   return _CAST(i64, lhs) op _CAST(f64, rhs);      \
        if constexpr(is_eq) return lhs op rhs;                              \
        vm->TypeError("unsupported operand type(s) for " #op );             \
        return false;                                                       \
    });                                                                     \
    _vm->bind##name(_vm->tp_float, [](VM* vm, PyObject* lhs, PyObject* rhs) {   \
        if(is_int(rhs))     return _CAST(f64, lhs) op _CAST(i64, rhs);          \
        if(is_float(rhs))   return _CAST(f64, lhs) op _CAST(f64, rhs);          \
        if constexpr(is_eq) return lhs op rhs;                                  \
        vm->TypeError("unsupported operand type(s) for " #op );                 \
        return false;                                                           \
    });

    BIND_NUM_LOGICAL_OPT(__lt__, <, false)
    BIND_NUM_LOGICAL_OPT(__le__, <=, false)
    BIND_NUM_LOGICAL_OPT(__gt__, >, false)
    BIND_NUM_LOGICAL_OPT(__ge__, >=, false)
    BIND_NUM_LOGICAL_OPT(__eq__, ==, true)

#undef BIND_NUM_ARITH_OPT
#undef BIND_NUM_LOGICAL_OPT

    _vm->bind_builtin_func<2>("super", [](VM* vm, ArgsView args) {
        vm->check_non_tagged_type(args[0], vm->tp_type);
        Type type = OBJ_GET(Type, args[0]);
        if(!vm->isinstance(args[1], type)){
            Str _0 = obj_type_name(vm, OBJ_GET(Type, vm->_t(args[1])));
            Str _1 = obj_type_name(vm, type);
            vm->TypeError("super(): " + _0.escape() + " is not an instance of " + _1.escape());
        }
        Type base = vm->_all_types[type].base;
        return vm->heap.gcnew(vm->tp_super, Super(args[1], base));
    });

    _vm->bind_builtin_func<2>("isinstance", [](VM* vm, ArgsView args) {
        vm->check_non_tagged_type(args[1], vm->tp_type);
        Type type = OBJ_GET(Type, args[1]);
        return VAR(vm->isinstance(args[0], type));
    });

    _vm->bind_builtin_func<0>("globals", [](VM* vm, ArgsView args) {
        PyObject* mod = vm->top_frame()->_module;
        return VAR(MappingProxy(mod));
    });

    _vm->bind_builtin_func<1>("id", [](VM* vm, ArgsView args) {
        PyObject* obj = args[0];
        if(is_tagged(obj)) return vm->None;
        return VAR_T(VoidP, obj);
    });

    _vm->bind_builtin_func<1>("staticmethod", [](VM* vm, ArgsView args) {
        return args[0];
    });

    _vm->bind_builtin_func<1>("__import__", [](VM* vm, ArgsView args) {
        return vm->py_import(CAST(Str&, args[0]));
    });

    _vm->bind_builtin_func<2>("divmod", [](VM* vm, ArgsView args) {
        i64 lhs = CAST(i64, args[0]);
        i64 rhs = CAST(i64, args[1]);
        return VAR(Tuple({VAR(lhs/rhs), VAR(lhs%rhs)}));
    });

    _vm->bind_builtin_func<1>("eval", [](VM* vm, ArgsView args) {
        CodeObject_ code = vm->compile(CAST(Str&, args[0]), "<eval>", EVAL_MODE, true);
        FrameId frame = vm->top_frame();
        return vm->_exec(code.get(), frame->_module, frame->_callable, frame->_locals);
    });

    _vm->bind_builtin_func<1>("exec", [](VM* vm, ArgsView args) {
        CodeObject_ code = vm->compile(CAST(Str&, args[0]), "<exec>", EXEC_MODE, true);
        FrameId frame = vm->top_frame();
        vm->_exec(code.get(), frame->_module, frame->_callable, frame->_locals);
        return vm->None;
    });

    _vm->bind_builtin_func<-1>("exit", [](VM* vm, ArgsView args) {
        if(args.size() == 0) std::exit(0);
        else if(args.size() == 1) std::exit(CAST(int, args[0]));
        else vm->TypeError("exit() takes at most 1 argument");
        return vm->None;
    });

    _vm->bind_builtin_func<1>("repr", CPP_LAMBDA(vm->py_repr(args[0])));

    _vm->bind_builtin_func<1>("len", [](VM* vm, ArgsView args){
        const PyTypeInfo* ti = vm->_inst_type_info(args[0]);
        if(ti->m__len__) return VAR(ti->m__len__(vm, args[0]));
        return vm->call_method(args[0], __len__);
    });

    _vm->bind_builtin_func<1>("hash", [](VM* vm, ArgsView args){
        i64 value = vm->py_hash(args[0]);
        if(((value << 2) >> 2) != value) value >>= 2;
        return VAR(value);
    });

    _vm->bind_builtin_func<1>("chr", [](VM* vm, ArgsView args) {
        i64 i = CAST(i64, args[0]);
        if (i < 0 || i > 128) vm->ValueError("chr() arg not in range(128)");
        return VAR(std::string(1, (char)i));
    });

    _vm->bind_builtin_func<1>("ord", [](VM* vm, ArgsView args) {
        const Str& s = CAST(Str&, args[0]);
        if (s.length()!=1) vm->TypeError("ord() expected an ASCII character");
        return VAR((i64)(s[0]));
    });

    _vm->bind_builtin_func<2>("hasattr", [](VM* vm, ArgsView args) {
        return VAR(vm->getattr(args[0], CAST(Str&, args[1]), false) != nullptr);
    });

    _vm->bind_builtin_func<3>("setattr", [](VM* vm, ArgsView args) {
        vm->setattr(args[0], CAST(Str&, args[1]), args[2]);
        return vm->None;
    });

    _vm->bind_builtin_func<2>("getattr", [](VM* vm, ArgsView args) {
        const Str& name = CAST(Str&, args[1]);
        return vm->getattr(args[0], name);
    });

    _vm->bind_builtin_func<1>("hex", [](VM* vm, ArgsView args) {
        std::stringstream ss;
        ss << std::hex << CAST(i64, args[0]);
        return VAR("0x" + ss.str());
    });

    _vm->bind_builtin_func<1>("iter", [](VM* vm, ArgsView args) {
        return vm->py_iter(args[0]);
    });

    _vm->bind_builtin_func<1>("next", [](VM* vm, ArgsView args) {
        return vm->py_next(args[0]);
    });

    _vm->bind_builtin_func<1>("dir", [](VM* vm, ArgsView args) {
        std::set<StrName> names;
        if(!is_tagged(args[0]) && args[0]->is_attr_valid()){
            std::vector<StrName> keys = args[0]->attr().keys();
            names.insert(keys.begin(), keys.end());
        }
        const NameDict& t_attr = vm->_t(args[0])->attr();
        std::vector<StrName> keys = t_attr.keys();
        names.insert(keys.begin(), keys.end());
        List ret;
        for (StrName name : names) ret.push_back(VAR(name.sv()));
        return VAR(std::move(ret));
    });

    _vm->bind__repr__(_vm->tp_object, [](VM* vm, PyObject* obj) {
        if(is_tagged(obj)) FATAL_ERROR();
        std::stringstream ss;
        ss << "<" << OBJ_NAME(vm->_t(obj)) << " object at 0x";
        ss << std::hex << reinterpret_cast<intptr_t>(obj) << ">";
        return VAR(ss.str());
    });

    _vm->bind__eq__(_vm->tp_object, [](VM* vm, PyObject* lhs, PyObject* rhs) { return lhs == rhs; });
    _vm->bind__hash__(_vm->tp_object, [](VM* vm, PyObject* obj) { return BITS(obj); });

    _vm->bind_constructor<2>("type", CPP_LAMBDA(vm->_t(args[1])));

    _vm->bind_constructor<-1>("range", [](VM* vm, ArgsView args) {
        args._begin += 1;   // skip cls
        Range r;
        switch (args.size()) {
            case 1: r.stop = CAST(i64, args[0]); break;
            case 2: r.start = CAST(i64, args[0]); r.stop = CAST(i64, args[1]); break;
            case 3: r.start = CAST(i64, args[0]); r.stop = CAST(i64, args[1]); r.step = CAST(i64, args[2]); break;
            default: vm->TypeError("expected 1-3 arguments, but got " + std::to_string(args.size()));
        }
        return VAR(r);
    });

    _vm->bind__iter__(_vm->tp_range, [](VM* vm, PyObject* obj) { return VAR_T(RangeIter, OBJ_GET(Range, obj)); });
    _vm->bind__repr__(_vm->_type("NoneType"), [](VM* vm, PyObject* obj) { return VAR("None"); });
    _vm->bind__json__(_vm->_type("NoneType"), [](VM* vm, PyObject* obj) { return VAR("null"); });

    _vm->bind__truediv__(_vm->tp_float, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        f64 value = CAST_F(rhs);
        return VAR(_CAST(f64, lhs) / value);
    });

    _vm->bind__truediv__(_vm->tp_int, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        f64 value = CAST_F(rhs);
        return VAR(_CAST(i64, lhs) / value);
    });

    auto py_number_pow = [](VM* vm, PyObject* lhs_, PyObject* rhs_) {
        if(is_both_int(lhs_, rhs_)){
            i64 lhs = _CAST(i64, lhs_);
            i64 rhs = _CAST(i64, rhs_);
            bool flag = false;
            if(rhs < 0) {flag = true; rhs = -rhs;}
            i64 ret = 1;
            while(rhs){
                if(rhs & 1) ret *= lhs;
                lhs *= lhs;
                rhs >>= 1;
            }
            if(flag) return VAR((f64)(1.0 / ret));
            return VAR(ret);
        }else{
            return VAR((f64)std::pow(CAST_F(lhs_), CAST_F(rhs_)));
        }
    };

    _vm->bind__pow__(_vm->tp_int, py_number_pow);
    _vm->bind__pow__(_vm->tp_float, py_number_pow);

    /************ int ************/
    _vm->bind_constructor<2>("int", [](VM* vm, ArgsView args) {
        if (is_type(args[1], vm->tp_float)) return VAR((i64)CAST(f64, args[1]));
        if (is_type(args[1], vm->tp_int)) return args[1];
        if (is_type(args[1], vm->tp_bool)) return VAR(_CAST(bool, args[1]) ? 1 : 0);
        if (is_type(args[1], vm->tp_str)) {
            const Str& s = CAST(Str&, args[1]);
            try{
                size_t parsed = 0;
                i64 val = Number::stoi(s.str(), &parsed, 10);
                if(parsed != s.length()) throw std::invalid_argument("<?>");
                return VAR(val);
            }catch(std::invalid_argument&){
                vm->ValueError("invalid literal for int(): " + s.escape());
            }
        }
        vm->TypeError("int() argument must be a int, float, bool or str");
        return vm->None;
    });

    _vm->bind__floordiv__(_vm->tp_int, [](VM* vm, PyObject* lhs_, PyObject* rhs_) {
        i64 rhs = CAST(i64, rhs_);
        return VAR(_CAST(i64, lhs_) / rhs);
    });

    _vm->bind__mod__(_vm->tp_int, [](VM* vm, PyObject* lhs_, PyObject* rhs_) {
        i64 rhs = CAST(i64, rhs_);
        return VAR(_CAST(i64, lhs_) % rhs);
    });

    _vm->bind__repr__(_vm->tp_int, [](VM* vm, PyObject* obj) { return VAR(std::to_string(_CAST(i64, obj))); });
    _vm->bind__json__(_vm->tp_int, [](VM* vm, PyObject* obj) { return VAR(std::to_string(_CAST(i64, obj))); });

    _vm->bind__neg__(_vm->tp_int, [](VM* vm, PyObject* obj) { return VAR(-_CAST(i64, obj)); });

    _vm->bind__hash__(_vm->tp_int, [](VM* vm, PyObject* obj) { return _CAST(i64, obj); });

#define INT_BITWISE_OP(name, op) \
    _vm->bind##name(_vm->tp_int, [](VM* vm, PyObject* lhs, PyObject* rhs) { \
        return VAR(_CAST(i64, lhs) op CAST(i64, rhs)); \
    });

    INT_BITWISE_OP(__lshift__, <<)
    INT_BITWISE_OP(__rshift__, >>)
    INT_BITWISE_OP(__and__, &)
    INT_BITWISE_OP(__or__, |)
    INT_BITWISE_OP(__xor__, ^)

#undef INT_BITWISE_OP

    /************ float ************/
    _vm->bind_constructor<2>("float", [](VM* vm, ArgsView args) {
        if (is_type(args[1], vm->tp_int)) return VAR((f64)CAST(i64, args[1]));
        if (is_type(args[1], vm->tp_float)) return args[1];
        if (is_type(args[1], vm->tp_bool)) return VAR(_CAST(bool, args[1]) ? 1.0 : 0.0);
        if (is_type(args[1], vm->tp_str)) {
            const Str& s = CAST(Str&, args[1]);
            if(s == "inf") return VAR(INFINITY);
            if(s == "-inf") return VAR(-INFINITY);
            try{
                f64 val = Number::stof(s.str());
                return VAR(val);
            }catch(std::invalid_argument&){
                vm->ValueError("invalid literal for float(): " + s.escape());
            }
        }
        vm->TypeError("float() argument must be a int, float, bool or str");
        return vm->None;
    });

    _vm->bind__hash__(_vm->tp_float, [](VM* vm, PyObject* obj) {
        f64 val = _CAST(f64, obj);
        return (i64)std::hash<f64>()(val);
    });

    _vm->bind__neg__(_vm->tp_float, [](VM* vm, PyObject* obj) { return VAR(-_CAST(f64, obj)); });

    _vm->bind__repr__(_vm->tp_float, [](VM* vm, PyObject* obj) {
        f64 val = _CAST(f64, obj);
        if(std::isinf(val) || std::isnan(val)) return VAR(std::to_string(val));
        std::stringstream ss;
        ss << std::setprecision(std::numeric_limits<f64>::max_digits10-2) << val;
        std::string s = ss.str();
        if(std::all_of(s.begin()+1, s.end(), isdigit)) s += ".0";
        return VAR(s);
    });
    _vm->bind__json__(_vm->tp_float, [](VM* vm, PyObject* obj) {
        f64 val = _CAST(f64, obj);
        if(std::isinf(val) || std::isnan(val)) vm->ValueError("cannot jsonify 'nan' or 'inf'");
        return VAR(std::to_string(val));
    });

    /************ str ************/
    _vm->bind_constructor<2>("str", CPP_LAMBDA(vm->py_str(args[1])));

    _vm->bind__hash__(_vm->tp_str, [](VM* vm, PyObject* obj) {
        return (i64)_CAST(Str&, obj).hash();
    });

    _vm->bind__add__(_vm->tp_str, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return VAR(_CAST(Str&, lhs) + CAST(Str&, rhs));
    });
    _vm->bind__len__(_vm->tp_str, [](VM* vm, PyObject* obj) {
        return (i64)_CAST(Str&, obj).u8_length();
    });
    _vm->bind__mul__(_vm->tp_str, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        const Str& self = _CAST(Str&, lhs);
        i64 n = CAST(i64, rhs);
        std::stringstream ss;
        for(i64 i = 0; i < n; i++) ss << self.sv();
        return VAR(ss.str());
    });
    _vm->bind__contains__(_vm->tp_str, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        const Str& self = _CAST(Str&, lhs);
        const Str& other = CAST(Str&, rhs);
        return self.index(other) != -1;
    });
    _vm->bind__str__(_vm->tp_str, [](VM* vm, PyObject* obj) { return obj; });
    _vm->bind__iter__(_vm->tp_str, [](VM* vm, PyObject* obj) { return VAR_T(StringIter, obj); });
    _vm->bind__repr__(_vm->tp_str, [](VM* vm, PyObject* obj) {
        const Str& self = _CAST(Str&, obj);
        return VAR(self.escape(true));
    });
    _vm->bind__json__(_vm->tp_str, [](VM* vm, PyObject* obj) {
        const Str& self = _CAST(Str&, obj);
        return VAR(self.escape(false));
    });
    _vm->bind__eq__(_vm->tp_str, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        if(!is_non_tagged_type(rhs, vm->tp_str)) return false;
        return _CAST(Str&, lhs) == _CAST(Str&, rhs);
    });
    _vm->bind__gt__(_vm->tp_str, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return _CAST(Str&, lhs) > CAST(Str&, rhs);
    });
    _vm->bind__lt__(_vm->tp_str, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return _CAST(Str&, lhs) < CAST(Str&, rhs);
    });
    _vm->bind__ge__(_vm->tp_str, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return _CAST(Str&, lhs) >= CAST(Str&, rhs);
    });
    _vm->bind__le__(_vm->tp_str, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return _CAST(Str&, lhs) <= CAST(Str&, rhs);
    });

    _vm->bind__getitem__(_vm->tp_str, [](VM* vm, PyObject* obj, PyObject* index) {
        const Str& self = _CAST(Str&, obj);
        if(is_non_tagged_type(index, vm->tp_slice)){
            const Slice& s = _CAST(Slice&, index);
            int start, stop, step;
            vm->parse_int_slice(s, self.u8_length(), start, stop, step);
            return VAR(self.u8_slice(start, stop, step));
        }
        int i = CAST(int, index);
        i = vm->normalized_index(i, self.u8_length());
        return VAR(self.u8_getitem(i));
    });

    _vm->bind_method<-1>("str", "replace", [](VM* vm, ArgsView args) {
        if(args.size() != 1+2 && args.size() != 1+3) vm->TypeError("replace() takes 2 or 3 arguments");
        const Str& self = _CAST(Str&, args[0]);
        const Str& old = CAST(Str&, args[1]);
        const Str& new_ = CAST(Str&, args[2]);
        int count = args.size()==1+3 ? CAST(int, args[3]) : -1;
        return VAR(self.replace(old, new_, count));
    });

    _vm->bind_method<1>("str", "index", [](VM* vm, ArgsView args) {
        const Str& self = _CAST(Str&, args[0]);
        const Str& sub = CAST(Str&, args[1]);
        int index = self.index(sub);
        if(index == -1) vm->ValueError("substring not found");
        return VAR(index);
    });

    _vm->bind_method<1>("str", "startswith", [](VM* vm, ArgsView args) {
        const Str& self = _CAST(Str&, args[0]);
        const Str& prefix = CAST(Str&, args[1]);
        return VAR(self.index(prefix) == 0);
    });

    _vm->bind_method<1>("str", "endswith", [](VM* vm, ArgsView args) {
        const Str& self = _CAST(Str&, args[0]);
        const Str& suffix = CAST(Str&, args[1]);
        int offset = self.length() - suffix.length();
        if(offset < 0) return vm->False;
        bool ok = memcmp(self.data+offset, suffix.data, suffix.length()) == 0;
        return VAR(ok);
    });

    _vm->bind_method<0>("str", "encode", [](VM* vm, ArgsView args) {
        const Str& self = _CAST(Str&, args[0]);
        std::vector<char> buffer(self.length());
        memcpy(buffer.data(), self.data, self.length());
        return VAR(Bytes(std::move(buffer)));
    });

    _vm->bind_method<1>("str", "join", [](VM* vm, ArgsView args) {
        auto _lock = vm->heap.gc_scope_lock();
        const Str& self = _CAST(Str&, args[0]);
        FastStrStream ss;
        PyObject* it = vm->py_iter(args[1]);     // strong ref
        PyObject* obj = vm->py_next(it);
        while(obj != vm->StopIteration){
            if(!ss.empty()) ss << self;
            ss << CAST(Str&, obj);
            obj = vm->py_next(it);
        }
        return VAR(ss.str());
    });

    _vm->bind_method<0>("str", "to_c_str", [](VM* vm, ArgsView args){
        const Str& self = _CAST(Str&, args[0]);
        return VAR(self.c_str_dup());
    });

    _vm->bind_func<1>("str", "from_c_str", [](VM* vm, ArgsView args){
        char* p = CAST(char*, args[0]);
        return VAR(Str(p));
    });

    _vm->bind_method<0>("str", "lower", [](VM* vm, ArgsView args) {
        const Str& self = _CAST(Str&, args[0]);
        return VAR(self.lower());
    });

    _vm->bind_method<0>("str", "upper", [](VM* vm, ArgsView args) {
        const Str& self = _CAST(Str&, args[0]);
        return VAR(self.upper());
    });

    /************ list ************/
    _vm->bind_constructor<2>("list", [](VM* vm, ArgsView args) {
        return vm->py_list(args[1]);
    });

    _vm->bind__contains__(_vm->tp_list, [](VM* vm, PyObject* obj, PyObject* item) {
        List& self = _CAST(List&, obj);
        for(PyObject* i: self) if(vm->py_equals(i, item)) return true;
        return false;
    });

    _vm->bind_method<1>("list", "count", [](VM* vm, ArgsView args) {
        List& self = _CAST(List&, args[0]);
        int count = 0;
        for(PyObject* i: self) if(vm->py_equals(i, args[1])) count++;
        return VAR(count);
    });

    _vm->bind__eq__(_vm->tp_list, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        List& a = _CAST(List&, lhs);
        List& b = _CAST(List&, rhs);
        if(a.size() != b.size()) return false;
        for(int i=0; i<a.size(); i++){
            if(!vm->py_equals(a[i], b[i])) return false;
        }
        return true;
    });

    _vm->bind_method<1>("list", "index", [](VM* vm, ArgsView args) {
        List& self = _CAST(List&, args[0]);
        PyObject* obj = args[1];
        for(int i=0; i<self.size(); i++){
            if(vm->py_equals(self[i], obj)) return VAR(i);
        }
        vm->ValueError(_CAST(Str&, vm->py_repr(obj)) + " is not in list");
        return vm->None;
    });

    _vm->bind_method<1>("list", "remove", [](VM* vm, ArgsView args) {
        List& self = _CAST(List&, args[0]);
        PyObject* obj = args[1];
        for(int i=0; i<self.size(); i++){
            if(vm->py_equals(self[i], obj)){
                self.erase(i);
                return vm->None;
            }
        }
        vm->ValueError(_CAST(Str&, vm->py_repr(obj)) + " is not in list");
        return vm->None;
    });

    _vm->bind_method<-1>("list", "pop", [](VM* vm, ArgsView args) {
        List& self = _CAST(List&, args[0]);
        if(args.size() == 1+0){
            if(self.empty()) vm->IndexError("pop from empty list");
            return self.popx_back();
        }
        if(args.size() == 1+1){
            int index = CAST(int, args[1]);
            index = vm->normalized_index(index, self.size());
            PyObject* ret = self[index];
            self.erase(index);
            return ret;
        }
        vm->TypeError("pop() takes at most 1 argument");
        return vm->None;
    });

    _vm->bind_method<1>("list", "append", [](VM* vm, ArgsView args) {
        List& self = _CAST(List&, args[0]);
        self.push_back(args[1]);
        return vm->None;
    });

    _vm->bind_method<1>("list", "extend", [](VM* vm, ArgsView args) {
        auto _lock = vm->heap.gc_scope_lock();
        List& self = _CAST(List&, args[0]);
        PyObject* it = vm->py_iter(args[1]);     // strong ref
        PyObject* obj = vm->py_next(it);
        while(obj != vm->StopIteration){
            self.push_back(obj);
            obj = vm->py_next(it);
        }
        return vm->None;
    });

    _vm->bind_method<0>("list", "reverse", [](VM* vm, ArgsView args) {
        List& self = _CAST(List&, args[0]);
        std::reverse(self.begin(), self.end());
        return vm->None;
    });

    _vm->bind__mul__(_vm->tp_list, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        const List& self = _CAST(List&, lhs);
        int n = CAST(int, rhs);
        List result;
        result.reserve(self.size() * n);
        for(int i = 0; i < n; i++) result.extend(self);
        return VAR(std::move(result));
    });

    _vm->bind_method<2>("list", "insert", [](VM* vm, ArgsView args) {
        List& self = _CAST(List&, args[0]);
        int index = CAST(int, args[1]);
        if(index < 0) index += self.size();
        if(index < 0) index = 0;
        if(index > self.size()) index = self.size();
        self.insert(index, args[2]);
        return vm->None;
    });

    _vm->bind_method<0>("list", "clear", [](VM* vm, ArgsView args) {
        _CAST(List&, args[0]).clear();
        return vm->None;
    });

    _vm->bind_method<0>("list", "copy", CPP_LAMBDA(VAR(_CAST(List, args[0]))));

    _vm->bind__hash__(_vm->tp_list, [](VM* vm, PyObject* obj) {
        vm->TypeError("unhashable type: 'list'");
        return (i64)0;
    });

    _vm->bind__add__(_vm->tp_list, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        const List& self = _CAST(List&, lhs);
        const List& other = CAST(List&, rhs);
        List new_list(self);    // copy construct
        new_list.extend(other);
        return VAR(std::move(new_list));
    });

    _vm->bind__len__(_vm->tp_list, [](VM* vm, PyObject* obj) {
        return (i64)_CAST(List&, obj).size();
    });
    _vm->bind__iter__(_vm->tp_list, [](VM* vm, PyObject* obj) {
        List& self = _CAST(List&, obj);
        return VAR_T(ArrayIter, obj, self.begin(), self.end());
    });
    _vm->bind__getitem__(_vm->tp_list, PyArrayGetItem<List>);
    _vm->bind__setitem__(_vm->tp_list, [](VM* vm, PyObject* obj, PyObject* index, PyObject* value){
        List& self = _CAST(List&, obj);
        int i = CAST(int, index);
        i = vm->normalized_index(i, self.size());
        self[i] = value;
    });
    _vm->bind__delitem__(_vm->tp_list, [](VM* vm, PyObject* obj, PyObject* index){
        List& self = _CAST(List&, obj);
        int i = CAST(int, index);
        i = vm->normalized_index(i, self.size());
        self.erase(i);
    });

    /************ tuple ************/
    _vm->bind_constructor<2>("tuple", [](VM* vm, ArgsView args) {
        List list = CAST(List, vm->py_list(args[1]));
        return VAR(Tuple(std::move(list)));
    });

    _vm->bind__contains__(_vm->tp_tuple, [](VM* vm, PyObject* obj, PyObject* item) {
        Tuple& self = _CAST(Tuple&, obj);
        for(PyObject* i: self) if(vm->py_equals(i, item)) return true;
        return false;
    });

    _vm->bind_method<1>("tuple", "count", [](VM* vm, ArgsView args) {
        Tuple& self = _CAST(Tuple&, args[0]);
        int count = 0;
        for(PyObject* i: self) if(vm->py_equals(i, args[1])) count++;
        return VAR(count);
    });

    _vm->bind__eq__(_vm->tp_tuple, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        const Tuple& self = _CAST(Tuple&, lhs);
        const Tuple& other = CAST(Tuple&, rhs);
        if(self.size() != other.size()) return false;
        for(int i = 0; i < self.size(); i++) {
            if(!vm->py_equals(self[i], other[i])) return false;
        }
        return true;
    });

    _vm->bind__hash__(_vm->tp_tuple, [](VM* vm, PyObject* obj) {
        i64 x = 1000003;
        const Tuple& items = CAST(Tuple&, obj);
        for (int i=0; i<items.size(); i++) {
            i64 y = vm->py_hash(items[i]);
            // recommended by Github Copilot
            x = x ^ (y + 0x9e3779b9 + (x << 6) + (x >> 2));
        }
        return x;
    });

    _vm->bind__iter__(_vm->tp_tuple, [](VM* vm, PyObject* obj) {
        Tuple& self = _CAST(Tuple&, obj);
        return VAR_T(ArrayIter, obj, self.begin(), self.end());
    });
    _vm->bind__getitem__(_vm->tp_tuple, PyArrayGetItem<Tuple>);
    _vm->bind__len__(_vm->tp_tuple, [](VM* vm, PyObject* obj) {
        return (i64)_CAST(Tuple&, obj).size();
    });

    /************ bool ************/
    _vm->bind_constructor<2>("bool", CPP_LAMBDA(VAR(vm->py_bool(args[1]))));
    _vm->bind__hash__(_vm->tp_bool, [](VM* vm, PyObject* obj) {
        return (i64)_CAST(bool, obj);
    });
    _vm->bind__repr__(_vm->tp_bool, [](VM* vm, PyObject* self) {
        bool val = _CAST(bool, self);
        return VAR(val ? "True" : "False");
    });
    _vm->bind__json__(_vm->tp_bool, [](VM* vm, PyObject* self) {
        bool val = _CAST(bool, self);
        return VAR(val ? "true" : "false");
    });

    _vm->bind__and__(_vm->tp_bool, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return VAR(_CAST(bool, lhs) && CAST(bool, rhs));
    });
    _vm->bind__or__(_vm->tp_bool, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return VAR(_CAST(bool, lhs) || CAST(bool, rhs));
    });
    _vm->bind__xor__(_vm->tp_bool, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return VAR(_CAST(bool, lhs) != CAST(bool, rhs));
    });
    _vm->bind__eq__(_vm->tp_bool, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return _CAST(bool, lhs) == CAST(bool, rhs);
    });
    _vm->bind__repr__(_vm->_type("ellipsis"), [](VM* vm, PyObject* self) {
        return VAR("Ellipsis");
    });

    /************ bytes ************/
    _vm->bind_constructor<2>("bytes", [](VM* vm, ArgsView args){
        List& list = CAST(List&, args[1]);
        std::vector<char> buffer(list.size());
        for(int i=0; i<list.size(); i++){
            i64 b = CAST(i64, list[i]);
            if(b<0 || b>255) vm->ValueError("byte must be in range[0, 256)");
            buffer[i] = (char)b;
        }
        return VAR(Bytes(std::move(buffer)));
    });

    _vm->bind__getitem__(_vm->tp_bytes, [](VM* vm, PyObject* obj, PyObject* index) {
        const Bytes& self = _CAST(Bytes&, obj);
        int i = CAST(int, index);
        i = vm->normalized_index(i, self.size());
        return VAR(self[i]);
    });

    _vm->bind__hash__(_vm->tp_bytes, [](VM* vm, PyObject* obj) {
        const Bytes& self = _CAST(Bytes&, obj);
        return (i64)std::hash<std::string>()(self.str());
    });

    _vm->bind__repr__(_vm->tp_bytes, [](VM* vm, PyObject* obj) {
        const Bytes& self = _CAST(Bytes&, obj);
        std::stringstream ss;
        ss << "b'";
        for(int i=0; i<self.size(); i++){
            ss << "\\x" << std::hex << std::setw(2) << std::setfill('0') << self[i];
        }
        ss << "'";
        return VAR(ss.str());
    });
    _vm->bind__len__(_vm->tp_bytes, [](VM* vm, PyObject* obj) {
        return (i64)_CAST(Bytes&, obj).size();
    });

    _vm->bind_method<0>("bytes", "decode", [](VM* vm, ArgsView args) {
        const Bytes& self = _CAST(Bytes&, args[0]);
        // TODO: check encoding is utf-8
        return VAR(Str(self.str()));
    });

    _vm->bind_method<0>("bytes", "to_char_array", [](VM* vm, ArgsView args) {
        const Bytes& self = _CAST(Bytes&, args[0]);
        void* buffer = malloc(self.size());
        memcpy(buffer, self.data(), self.size());
        return VAR_T(VoidP, buffer);
    });

    _vm->bind_func<2>("bytes", "from_char_array", [](VM* vm, ArgsView args) {
        const VoidP& data = _CAST(VoidP&, args[0]);
        int size = CAST(int, args[1]);
        std::vector<char> buffer(size);
        memcpy(buffer.data(), data.ptr, size);
        return VAR(Bytes(std::move(buffer)));
    });

    _vm->bind__eq__(_vm->tp_bytes, [](VM* vm, PyObject* lhs, PyObject* rhs) {
        return _CAST(Bytes&, lhs) == _CAST(Bytes&, rhs);
    });
    /************ slice ************/
    _vm->bind_constructor<4>("slice", [](VM* vm, ArgsView args) {
        return VAR(Slice(args[1], args[2], args[3]));
    });

    _vm->bind__repr__(_vm->tp_slice, [](VM* vm, PyObject* obj) {
        const Slice& self = _CAST(Slice&, obj);
        std::stringstream ss;
        ss << "slice(";
        ss << CAST(Str, vm->py_repr(self.start)) << ", ";
        ss << CAST(Str, vm->py_repr(self.stop)) << ", ";
        ss << CAST(Str, vm->py_repr(self.step)) << ")";
        return VAR(ss.str());
    });

    /************ mappingproxy ************/
    _vm->bind_method<0>("mappingproxy", "keys", [](VM* vm, ArgsView args) {
        MappingProxy& self = _CAST(MappingProxy&, args[0]);
        List keys;
        for(StrName name : self.attr().keys()) keys.push_back(VAR(name.sv()));
        return VAR(std::move(keys));
    });

    _vm->bind_method<0>("mappingproxy", "values", [](VM* vm, ArgsView args) {
        MappingProxy& self = _CAST(MappingProxy&, args[0]);
        List values;
        for(auto& item : self.attr().items()) values.push_back(item.second);
        return VAR(std::move(values));
    });

    _vm->bind_method<0>("mappingproxy", "items", [](VM* vm, ArgsView args) {
        MappingProxy& self = _CAST(MappingProxy&, args[0]);
        List items;
        for(auto& item : self.attr().items()){
            PyObject* t = VAR(Tuple({VAR(item.first.sv()), item.second}));
            items.push_back(std::move(t));
        }
        return VAR(std::move(items));
    });

    _vm->bind__len__(_vm->tp_mappingproxy, [](VM* vm, PyObject* obj) {
        return (i64)_CAST(MappingProxy&, obj).attr().size();
    });

    _vm->bind__getitem__(_vm->tp_mappingproxy, [](VM* vm, PyObject* obj, PyObject* index) {
        MappingProxy& self = _CAST(MappingProxy&, obj);
        StrName key = CAST(Str&, index);
        PyObject* ret = self.attr().try_get(key);
        if(ret == nullptr) vm->AttributeError(key.sv());
        return ret;
    });

    _vm->bind__repr__(_vm->tp_mappingproxy, [](VM* vm, PyObject* obj) {
        MappingProxy& self = _CAST(MappingProxy&, obj);
        std::stringstream ss;
        ss << "mappingproxy({";
        bool first = true;
        for(auto& item : self.attr().items()){
            if(!first) ss << ", ";
            first = false;
            ss << item.first.escape() << ": " << CAST(Str, vm->py_repr(item.second));
        }
        ss << "})";
        return VAR(ss.str());
    });

    _vm->bind__contains__(_vm->tp_mappingproxy, [](VM* vm, PyObject* obj, PyObject* key) {
        MappingProxy& self = _CAST(MappingProxy&, obj);
        return self.attr().contains(CAST(Str&, key));
    });

    /************ dict ************/
    _vm->bind_constructor<-1>("dict", [](VM* vm, ArgsView args){
        return VAR(Dict(vm));
    });

    _vm->bind_method<-1>("dict", "__init__", [](VM* vm, ArgsView args){
        if(args.size() == 1+0) return vm->None;
        if(args.size() == 1+1){
            auto _lock = vm->heap.gc_scope_lock();
            Dict& self = _CAST(Dict&, args[0]);
            List& list = CAST(List&, args[1]);
            for(PyObject* item : list){
                Tuple& t = CAST(Tuple&, item);
                if(t.size() != 2){
                    vm->ValueError("dict() takes an iterable of tuples (key, value)");
                    return vm->None;
                }
                self.set(t[0], t[1]);
            }
            return vm->None;
        }
        vm->TypeError("dict() takes at most 1 argument");
        return vm->None;
    });

    _vm->bind__len__(_vm->tp_dict, [](VM* vm, PyObject* obj) {
        return (i64)_CAST(Dict&, obj).size();
    });

    _vm->bind__getitem__(_vm->tp_dict, [](VM* vm, PyObject* obj, PyObject* index) {
        Dict& self = _CAST(Dict&, obj);
        PyObject* ret = self.try_get(index);
        if(ret == nullptr) vm->KeyError(index);
        return ret;
    });

    _vm->bind__setitem__(_vm->tp_dict, [](VM* vm, PyObject* obj, PyObject* key, PyObject* value) {
        Dict& self = _CAST(Dict&, obj);
        self.set(key, value);
    });

    _vm->bind__delitem__(_vm->tp_dict, [](VM* vm, PyObject* obj, PyObject* key) {
        Dict& self = _CAST(Dict&, obj);
        if(!self.contains(key)) vm->KeyError(key);
        self.erase(key);
    });

    _vm->bind_method<1>("dict", "pop", [](VM* vm, ArgsView args) {
        Dict& self = _CAST(Dict&, args[0]);
        PyObject* value = self.try_get(args[1]);
        if(value == nullptr) vm->KeyError(args[1]);
        self.erase(args[1]);
        return value;
    });

    _vm->bind__contains__(_vm->tp_dict, [](VM* vm, PyObject* obj, PyObject* key) {
        Dict& self = _CAST(Dict&, obj);
        return self.contains(key);
    });

    _vm->bind_method<-1>("dict", "get", [](VM* vm, ArgsView args) {
        Dict& self = _CAST(Dict&, args[0]);
        if(args.size() == 1+1){
            PyObject* ret = self.try_get(args[1]);
            if(ret != nullptr) return ret;
            return vm->None;
        }else if(args.size() == 1+2){
            PyObject* ret = self.try_get(args[1]);
            if(ret != nullptr) return ret;
            return args[2];
        }
        vm->TypeError("get() takes at most 2 arguments");
        return vm->None;
    });

    _vm->bind_method<0>("dict", "keys", [](VM* vm, ArgsView args) {
        Dict& self = _CAST(Dict&, args[0]);
        List keys;
        for(auto& item : self.items()) keys.push_back(item.first);
        return VAR(std::move(keys));
    });

    _vm->bind_method<0>("dict", "values", [](VM* vm, ArgsView args) {
        Dict& self = _CAST(Dict&, args[0]);
        List values;
        for(auto& item : self.items()) values.push_back(item.second);
        return VAR(std::move(values));
    });

    _vm->bind_method<0>("dict", "items", [](VM* vm, ArgsView args) {
        Dict& self = _CAST(Dict&, args[0]);
        List items;
        for(auto& item : self.items()){
            PyObject* t = VAR(Tuple({item.first, item.second}));
            items.push_back(std::move(t));
        }
        return VAR(std::move(items));
    });

    _vm->bind_method<1>("dict", "update", [](VM* vm, ArgsView args) {
        Dict& self = _CAST(Dict&, args[0]);
        const Dict& other = CAST(Dict&, args[1]);
        self.update(other);
        return vm->None;
    });

    _vm->bind_method<0>("dict", "copy", [](VM* vm, ArgsView args) {
        const Dict& self = _CAST(Dict&, args[0]);
        return VAR(self);
    });

    _vm->bind_method<0>("dict", "clear", [](VM* vm, ArgsView args) {
        Dict& self = _CAST(Dict&, args[0]);
        self.clear();
        return vm->None;
    });

    _vm->bind__repr__(_vm->tp_dict, [](VM* vm, PyObject* obj) {
        Dict& self = _CAST(Dict&, obj);
        std::stringstream ss;
        ss << "{";
        bool first = true;
        for(auto& item : self.items()){
            if(!first) ss << ", ";
            first = false;
            Str key = CAST(Str&, vm->py_repr(item.first));
            Str value = CAST(Str&, vm->py_repr(item.second));
            ss << key << ": " << value;
        }
        ss << "}";
        return VAR(ss.str());
    });

    _vm->bind__json__(_vm->tp_dict, [](VM* vm, PyObject* obj) {
        Dict& self = _CAST(Dict&, obj);
        std::stringstream ss;
        ss << "{";
        bool first = true;
        for(auto& item : self.items()){
            if(!first) ss << ", ";
            first = false;
            Str key = CAST(Str&, item.first).escape(false);
            Str value = CAST(Str&, vm->py_json(item.second));
            ss << key << ": " << value;
        }
        ss << "}";
        return VAR(ss.str());
    });

    _vm->bind__eq__(_vm->tp_dict, [](VM* vm, PyObject* a, PyObject* b) {
        Dict& self = _CAST(Dict&, a);
        if(!is_non_tagged_type(b, vm->tp_dict)) return false;
        Dict& other = _CAST(Dict&, b);
        if(self.size() != other.size()) return false;
        for(auto& item : self.items()){
            PyObject* value = other.try_get(item.first);
            if(value == nullptr) return false;
            if(!vm->py_equals(item.second, value)) return false;
        }
        return true;
    });
    /************ property ************/
    _vm->bind_constructor<-1>("property", [](VM* vm, ArgsView args) {
        if(args.size() == 1+1){
            return VAR(Property(args[1], vm->None));
        }else if(args.size() == 1+2){
            return VAR(Property(args[1], args[2]));
        }
        vm->TypeError("property() takes at most 2 arguments");
        return vm->None;
    });

    RangeIter::register_class(_vm, _vm->builtins);
    ArrayIter::register_class(_vm, _vm->builtins);
    StringIter::register_class(_vm, _vm->builtins);
    Generator::register_class(_vm, _vm->builtins);
}

inline void add_module_time(VM* vm){
    PyObject* mod = vm->new_module("time");
    vm->bind_func<0>(mod, "time", [](VM* vm, ArgsView args) {
        auto now = std::chrono::system_clock::now();
        return VAR(std::chrono::duration_cast<std::chrono::milliseconds>(now.time_since_epoch()).count() / 1000.0);
    });

    vm->bind_func<1>(mod, "sleep", [](VM* vm, ArgsView args) {
        f64 seconds = CAST_F(args[0]);
        auto begin = std::chrono::system_clock::now();
        while(true){
            auto now = std::chrono::system_clock::now();
            f64 elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - begin).count() / 1000.0;
            if(elapsed >= seconds) break;
        }
        return vm->None;
    });

    vm->bind_func<0>(mod, "localtime", [](VM* vm, ArgsView args) {
        auto now = std::chrono::system_clock::now();
        std::time_t t = std::chrono::system_clock::to_time_t(now);
        std::tm* tm = std::localtime(&t);
        Dict d(vm);
        d.set(VAR("tm_year"), VAR(tm->tm_year + 1900));
        d.set(VAR("tm_mon"), VAR(tm->tm_mon + 1));
        d.set(VAR("tm_mday"), VAR(tm->tm_mday));
        d.set(VAR("tm_hour"), VAR(tm->tm_hour));
        d.set(VAR("tm_min"), VAR(tm->tm_min));
        d.set(VAR("tm_sec"), VAR(tm->tm_sec + 1));
        d.set(VAR("tm_wday"), VAR((tm->tm_wday + 6) % 7));
        d.set(VAR("tm_yday"), VAR(tm->tm_yday + 1));
        d.set(VAR("tm_isdst"), VAR(tm->tm_isdst));
        return VAR(std::move(d));
    });
}

struct PyREPL{
    PY_CLASS(PyREPL, sys, _repl)

    REPL* repl;

    PyREPL(VM* vm){ repl = new REPL(vm); }
    ~PyREPL(){ delete repl; }

    PyREPL(const PyREPL&) = delete;
    PyREPL& operator=(const PyREPL&) = delete;

    PyREPL(PyREPL&& other) noexcept{
        repl = other.repl;
        other.repl = nullptr;
    }

    struct TempOut{
        PrintFunc backup;
        VM* vm;
        TempOut(VM* vm, PrintFunc f){
            this->vm = vm;
            this->backup = vm->_stdout;
            vm->_stdout = f;
        }
        ~TempOut(){
            vm->_stdout = backup;
        }
        TempOut(const TempOut&) = delete;
        TempOut& operator=(const TempOut&) = delete;
        TempOut(TempOut&&) = delete;
        TempOut& operator=(TempOut&&) = delete;
    };

    static void _register(VM* vm, PyObject* mod, PyObject* type){
        vm->bind_constructor<1>(type, [](VM* vm, ArgsView args){
            return VAR_T(PyREPL, vm);
        });

        vm->bind_method<1>(type, "input", [](VM* vm, ArgsView args){
            PyREPL& self = _CAST(PyREPL&, args[0]);
            const Str& s = CAST(Str&, args[1]);
            static std::stringstream ss_out;
            ss_out.str("");
            TempOut _(vm, [](VM* vm, const Str& s){ ss_out << s; });
            bool ok = self.repl->input(s.str());
            return VAR(Tuple({VAR(ok), VAR(ss_out.str())}));
        });
    }
};

inline void add_module_sys(VM* vm){
    PyObject* mod = vm->new_module("sys");
    PyREPL::register_class(vm, mod);
    vm->setattr(mod, "version", VAR(PK_VERSION));

    PyObject* stdout_ = vm->heap.gcnew<DummyInstance>(vm->tp_object, {});
    PyObject* stderr_ = vm->heap.gcnew<DummyInstance>(vm->tp_object, {});
    PyObject* stdin_ = vm->heap.gcnew<DummyInstance>(vm->tp_object, {});
    vm->setattr(mod, "stdout", stdout_);
    vm->setattr(mod, "stderr", stderr_);
    vm->setattr(mod, "stdin", stdin_);

    vm->bind_func<1>(stdout_, "write", [](VM* vm, ArgsView args) {
        vm->_stdout(vm, CAST(Str&, args[0]));
        return vm->None;
    });

    vm->bind_func<1>(stderr_, "write", [](VM* vm, ArgsView args) {
        vm->_stderr(vm, CAST(Str&, args[0]));
        return vm->None;
    });
}

inline void add_module_json(VM* vm){
    PyObject* mod = vm->new_module("json");
    vm->bind_func<1>(mod, "loads", [](VM* vm, ArgsView args) {
        const Str& expr = CAST(Str&, args[0]);
        CodeObject_ code = vm->compile(expr, "<json>", JSON_MODE);
        return vm->_exec(code, vm->top_frame()->_module);
    });

    vm->bind_func<1>(mod, "dumps", [](VM* vm, ArgsView args) {
        return vm->py_json(args[0]);
    });
}


// https://docs.python.org/3.5/library/math.html
inline void add_module_math(VM* vm){
    PyObject* mod = vm->new_module("math");
    mod->attr().set("pi", VAR(3.1415926535897932384));
    mod->attr().set("e" , VAR(2.7182818284590452354));
    mod->attr().set("inf", VAR(std::numeric_limits<double>::infinity()));
    mod->attr().set("nan", VAR(std::numeric_limits<double>::quiet_NaN()));

    vm->bind_func<1>(mod, "ceil", CPP_LAMBDA(VAR((i64)std::ceil(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "fabs", CPP_LAMBDA(VAR(std::fabs(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "floor", CPP_LAMBDA(VAR((i64)std::floor(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "fsum", [](VM* vm, ArgsView args) {
        List& list = CAST(List&, args[0]);
        double sum = 0;
        double c = 0;
        for(PyObject* arg : list){
            double x = CAST_F(arg);
            double y = x - c;
            double t = sum + y;
            c = (t - sum) - y;
            sum = t;
        }
        return VAR(sum);
    });
    vm->bind_func<2>(mod, "gcd", [](VM* vm, ArgsView args) {
        i64 a = CAST(i64, args[0]);
        i64 b = CAST(i64, args[1]);
        if(a < 0) a = -a;
        if(b < 0) b = -b;
        while(b != 0){
            i64 t = b;
            b = a % b;
            a = t;
        }
        return VAR(a);
    });

    vm->bind_func<1>(mod, "isfinite", CPP_LAMBDA(VAR(std::isfinite(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "isinf", CPP_LAMBDA(VAR(std::isinf(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "isnan", CPP_LAMBDA(VAR(std::isnan(CAST_F(args[0])))));

    vm->bind_func<1>(mod, "exp", CPP_LAMBDA(VAR(std::exp(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "log", CPP_LAMBDA(VAR(std::log(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "log2", CPP_LAMBDA(VAR(std::log2(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "log10", CPP_LAMBDA(VAR(std::log10(CAST_F(args[0])))));

    vm->bind_func<2>(mod, "pow", CPP_LAMBDA(VAR(std::pow(CAST_F(args[0]), CAST_F(args[1])))));
    vm->bind_func<1>(mod, "sqrt", CPP_LAMBDA(VAR(std::sqrt(CAST_F(args[0])))));

    vm->bind_func<1>(mod, "acos", CPP_LAMBDA(VAR(std::acos(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "asin", CPP_LAMBDA(VAR(std::asin(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "atan", CPP_LAMBDA(VAR(std::atan(CAST_F(args[0])))));
    vm->bind_func<2>(mod, "atan2", CPP_LAMBDA(VAR(std::atan2(CAST_F(args[0]), CAST_F(args[1])))));

    vm->bind_func<1>(mod, "cos", CPP_LAMBDA(VAR(std::cos(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "sin", CPP_LAMBDA(VAR(std::sin(CAST_F(args[0])))));
    vm->bind_func<1>(mod, "tan", CPP_LAMBDA(VAR(std::tan(CAST_F(args[0])))));
    
    vm->bind_func<1>(mod, "degrees", CPP_LAMBDA(VAR(CAST_F(args[0]) * 180 / 3.1415926535897932384)));
    vm->bind_func<1>(mod, "radians", CPP_LAMBDA(VAR(CAST_F(args[0]) * 3.1415926535897932384 / 180)));

    vm->bind_func<1>(mod, "modf", [](VM* vm, ArgsView args) {
        f64 i;
        f64 f = std::modf(CAST_F(args[0]), &i);
        return VAR(Tuple({VAR(f), VAR(i)}));
    });
}

inline void add_module_traceback(VM* vm){
    PyObject* mod = vm->new_module("traceback");
    vm->bind_func<0>(mod, "print_exc", [](VM* vm, ArgsView args) {
        if(vm->_last_exception==nullptr) vm->ValueError("no exception");
        Exception& e = CAST(Exception&, vm->_last_exception);
        vm->_stdout(vm, e.summary());
        return vm->None;
    });

    vm->bind_func<0>(mod, "format_exc", [](VM* vm, ArgsView args) {
        if(vm->_last_exception==nullptr) vm->ValueError("no exception");
        Exception& e = CAST(Exception&, vm->_last_exception);
        return VAR(e.summary());
    });
}

inline void add_module_dis(VM* vm){
    PyObject* mod = vm->new_module("dis");
    vm->bind_func<1>(mod, "dis", [](VM* vm, ArgsView args) {
        if(is_type(args[0], vm->tp_str)){
            const Str& source = CAST(Str, args[0]);
            CodeObject_ code = vm->compile(source, "<dis>", EXEC_MODE);
            vm->_stdout(vm, vm->disassemble(code));
            return vm->None;
        }
        PyObject* f = args[0];
        if(is_type(f, vm->tp_bound_method)) f = CAST(BoundMethod, args[0]).func;
        CodeObject_ code = CAST(Function&, f).decl->code;
        vm->_stdout(vm, vm->disassemble(code));
        return vm->None;
    });
}

inline void add_module_gc(VM* vm){
    PyObject* mod = vm->new_module("gc");
    vm->bind_func<0>(mod, "collect", CPP_LAMBDA(VAR(vm->heap.collect())));
}

inline void VM::post_init(){
    init_builtins(this);
#if !DEBUG_NO_BUILTIN_MODULES
    add_module_sys(this);
    add_module_traceback(this);
    add_module_time(this);
    add_module_json(this);
    add_module_math(this);
    add_module_re(this);
    add_module_dis(this);
    add_module_c(this);
    add_module_gc(this);
    add_module_random(this);
    add_module_base64(this);

    for(const char* name: {"this", "functools", "collections", "heapq", "bisect"}){
        _lazy_modules[name] = kPythonLibs[name];
    }

    CodeObject_ code = compile(kPythonLibs["builtins"], "<builtins>", EXEC_MODE);
    this->_exec(code, this->builtins);
    code = compile(kPythonLibs["_set"], "<set>", EXEC_MODE);
    this->_exec(code, this->builtins);

    // property is defined in builtins.py so we need to add it after builtins is loaded
    _t(tp_object)->attr().set("__class__", property(CPP_LAMBDA(vm->_t(args[0]))));
    _t(tp_type)->attr().set("__base__", property([](VM* vm, ArgsView args){
        const PyTypeInfo& info = vm->_all_types[OBJ_GET(Type, args[0])];
        return info.base.index == -1 ? vm->None : vm->_all_types[info.base].obj;
    }));
    _t(tp_type)->attr().set("__name__", property([](VM* vm, ArgsView args){
        const PyTypeInfo& info = vm->_all_types[OBJ_GET(Type, args[0])];
        return VAR(info.name);
    }));

    _t(tp_bound_method)->attr().set("__self__", property([](VM* vm, ArgsView args){
        return CAST(BoundMethod&, args[0]).self;
    }));
    _t(tp_bound_method)->attr().set("__func__", property([](VM* vm, ArgsView args){
        return CAST(BoundMethod&, args[0]).func;
    }));

    bind__eq__(tp_bound_method, [](VM* vm, PyObject* lhs, PyObject* rhs){
        if(!is_non_tagged_type(rhs, vm->tp_bound_method)) return false;
        return _CAST(BoundMethod&, lhs) == _CAST(BoundMethod&, rhs);
    });
    _t(tp_slice)->attr().set("start", property([](VM* vm, ArgsView args){
        return CAST(Slice&, args[0]).start;
    }));
    _t(tp_slice)->attr().set("stop", property([](VM* vm, ArgsView args){
        return CAST(Slice&, args[0]).stop;
    }));
    _t(tp_slice)->attr().set("step", property([](VM* vm, ArgsView args){
        return CAST(Slice&, args[0]).step;
    }));

    _t(tp_object)->attr().set("__dict__", property([](VM* vm, ArgsView args){
        if(is_tagged(args[0]) || !args[0]->is_attr_valid()) vm->AttributeError("'__dict__'");
        return VAR(MappingProxy(args[0]));
    }));

    if(enable_os){
        add_module_io(this);
        add_module_os(this);
        add_module_requests(this);
        _import_handler = _default_import_handler;
    }

    add_module_linalg(this);
    add_module_easing(this);
#endif
}

}   // namespace pkpy

/*************************GLOBAL NAMESPACE*************************/
extern "C" {
    PK_LEGACY_EXPORT
    void pkpy_free(void* p){
        free(p);
    }

    PK_LEGACY_EXPORT
    void pkpy_vm_exec(pkpy::VM* vm, const char* source){
        vm->exec(source, "main.py", pkpy::EXEC_MODE);
    }

    PK_LEGACY_EXPORT
    void pkpy_vm_exec_2(pkpy::VM* vm, const char* source, const char* filename, int mode, const char* module){
        pkpy::PyObject* mod;
        if(module == nullptr) mod = vm->_main;
        else{
            mod = vm->_modules.try_get(module);
            if(mod == nullptr) return;
        }
        vm->exec(source, filename, (pkpy::CompileMode)mode, mod);
    }

    PK_LEGACY_EXPORT
    pkpy::REPL* pkpy_new_repl(pkpy::VM* vm){
        pkpy::REPL* p = new pkpy::REPL(vm);
        return p;
    }

    PK_LEGACY_EXPORT
    bool pkpy_repl_input(pkpy::REPL* r, const char* line){
        return r->input(line);
    }

    PK_LEGACY_EXPORT
    void pkpy_vm_add_module(pkpy::VM* vm, const char* name, const char* source){
        vm->_lazy_modules[name] = source;
    }

    PK_LEGACY_EXPORT
    pkpy::VM* pkpy_new_vm(bool enable_os=true){
        pkpy::VM* p = new pkpy::VM(enable_os);
        return p;
    }

    PK_LEGACY_EXPORT
    void pkpy_delete_vm(pkpy::VM* vm){
        delete vm;
    }

    PK_LEGACY_EXPORT
    void pkpy_delete_repl(pkpy::REPL* repl){
        delete repl;
    }

    PK_LEGACY_EXPORT
    void pkpy_vm_gc_on_delete(pkpy::VM* vm, void (*f)(pkpy::VM *, pkpy::PyObject *)){
        vm->heap._gc_on_delete = f;
    }
}