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https://github.com/pocketpy/pocketpy
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@ -1,5 +1,5 @@
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---
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icon: package
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icon: package-dependencies
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label: box2d
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---
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@ -1,5 +1,5 @@
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---
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icon: package
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icon: package-dependencies
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label: os
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---
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@ -10,12 +10,14 @@ Some python objects have an instance dict, a.k.a, `__dict__` in cpython.
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You can use `obj->attr()` to manipulate the instance dict of an object.
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```cpp
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VM* vm = new VM();
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// get the `builtin` module
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PyObject* builtins = vm->builtins;
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// get `dict` type
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PyObject* dict = builtins->attr("dict");
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// set `pi = 3.14`
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builtins->attr().set("pi", VAR(3.14));
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builtins->attr().set("pi", py_var(vm, 3.14));
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```
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However, you cannot call `attr` on an object which does not have an instance dict.
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@ -23,7 +25,7 @@ For example, the `int` object.
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```cpp
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// create a `int` object
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PyObject* obj = VAR(1);
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PyObject* obj = py_var(vm, 1);
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// THIS IS WRONG!! WILL LEAD TO A SEGFAULT!!
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PyObject* add = obj->attr("__add__");
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```
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@ -33,7 +35,7 @@ To determine whether an object has instance dict or not, you can use this snippe
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```cpp
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// 1. call `is_tagged` to check the object supports `->` operator
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// 2. call `is_attr_valid` to check the existence of instance dict
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PyObject* obj = VAR(1);
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PyObject* obj = py_var(vm, 1);
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bool ok = !is_tagged(obj) && obj->is_attr_valid(); // false
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```
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@ -51,16 +53,16 @@ or throw an `AttributeError` depending on the value of `throw_err`.
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```cpp
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// create a `int` object
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PyObject* obj = VAR(1);
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PyObject* obj = py_var(vm, 1);
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// get its `__add__` method, which is a `bound_method` object
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PyObject* add = vm->getattr(obj, "__add__");
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// call it (equivalent to `1 + 2`)
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PyObject* ret = vm->call(add, VAR(2));
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PyObject* ret = vm->call(add, py_var(vm, 2););
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// get the result
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int result = CAST(int, ret);
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int result = py_cast<int>(vm, ret);
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std::cout << result << std::endl; // 3
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```
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@ -34,12 +34,14 @@ PyObject* obj = vm->call(tp); // this is a `dict`
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And set a key-value pair,
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```cpp
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vm->call_method(obj, "__setitem__", VAR("a"), VAR(5));
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PyObject* _0 = py_var(vm, "a");
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PyObject* _1 = py_var(vm, 5);
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vm->call_method(obj, "__setitem__", _0, _1);
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```
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And get the value,
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```cpp
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PyObject* ret = vm->call_method(obj, "__getitem__", VAR("a"));
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std::cout << CAST(i64, ret) << std::endl;
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PyObject* ret = vm->call_method(obj, "__getitem__", _0);
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std::cout << py_cast<int>(vm, i64);
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```
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@ -11,13 +11,13 @@ In pkpy, any python object is represented by a `PyObject*`.
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A set of overloaded function `PyObject* py_var(VM* vm, ...)` were implemented to
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create a `PyObject*` from a supported C type.
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In order to make it less verbose, we usually use macro `VAR(...)`, which is just a wrapper of `py_var`.
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For example, create a python `int` object from a C `i64` type:
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Assume we have a `VM* vm` instance.
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You can create a python `int` object from a C `i64` type:
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```cpp
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i64 i = 2;
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PyObject* obj = VAR(i);
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PyObject* obj = py_var(vm, i);
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```
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Each python type has a corresponding C type, for example, `int` in python is `i64` in C.
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@ -26,7 +26,7 @@ For strings, we have defined
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a set of overloaded version including `const char*`, `std::string`, `std::string_view`, `Str`, etc.
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```cpp
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PyObject* obj = VAR("abc"); // create a python str object
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PyObject* obj = py_var(vm, "abc"); // create a python str object
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```
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A more complex example is to create a python `list`.
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@ -35,50 +35,49 @@ In the following code, we create a `list` equals to `[0, 1, 2, 3]`.
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```cpp
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List list;
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for (i64 i = 0; i < 4; i++) {
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list.push_back(VAR(i));
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list.push_back(py_var(vm, i));
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}
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obj = VAR(std::move(list)); // create a python list object
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obj = py_var(vm, std::move(list)); // create a python list object
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```
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Please note that `std::move` is used here to avoid unnecessary copy.
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Most types have both a rvalue and a lvalue version of `VAR` function.
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Most types have both a rvalue and a lvalue version of `py_var` function.
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### Access internal C type of `PyObject*`
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A set of template function `T py_cast<T>(VM* vm, PyObject* obj)` were implemented
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for each supported C type. We usually use macro `CAST(T, ...)` to make it less verbose.
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A set of template function `T py_cast<T>(VM* vm, PyObject* obj)` were implemented.
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```cpp
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i64 i = 2;
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PyObject* obj = VAR(i);
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PyObject* obj = py_var(vm, i);
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// cast a PyObject* to C i64
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i64 j = CAST(i64, obj);
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i64 j = py_cast<i64>(vm, obj);
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```
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The `CAST` function will check the type of `obj` before casting.
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The `py_cast` function will check the type of `obj` before casting.
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If the type is not matched, a `TypeError` will be thrown.
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However, this type check has a cost. If you are sure about the type of `obj`,
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you can use the underscore version `_CAST` to skip the type check.
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you can use the underscore version `_py_cast` to skip the type check.
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```cpp
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// cast a PyObject* to C i64 (unsafe but faster)
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i64 j = _CAST(i64, obj);
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i64 j = _py_cast<i64>(vm, obj);
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```
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For complex objects like `list`, we can use reference cast to avoid unnecessary copy.
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```cpp
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PyObject* obj = VAR(List());
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PyObject* obj = py_var(vm, List());
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// reference cast (no copy)
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List& list = CAST(List&, obj);
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List& list = py_cast<List&>(vm, obj);
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```
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### Check type of `PyObject*`
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Each `PyObject*` has a `Type` field to indicate its type.
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Each `PyObject*` has a `Type type` field to indicate its type.
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`Type` is just an integer which is the global index in `vm->_all_types`.
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`VM` class has a set of predefined `Type` constants for quick access.
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@ -86,7 +85,7 @@ They are prefixed by `tp_`. For example, `tp_object`(object),
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`tp_int`(int), `tp_str`(str), `tp_list`(list), etc.
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Types are divided into **tagged type** and **non-tagged type**.
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+ `int` and `float` are tagged type.
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+ `int` (small) and `float` are tagged type.
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+ Other types are non-tagged type.
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To determine whether a `PyObject*` is of a specific type,
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@ -99,7 +98,7 @@ you can use the following functions:
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+ `bool is_non_tagged_type(PyObject* obj, Type type)`
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```cpp
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PyObject* obj = VAR(1);
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PyObject* obj = py_var(vm, 1);
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bool ok = is_type(obj, vm->tp_int); // true
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ok = is_int(obj); // true
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@ -28,17 +28,18 @@ A native module is a module written in c++ or mixed c++/python.
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Native modules are always compiled and executed when the VM is created.
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To creata a native module,
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use `vm->new_module(...)`.
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use `vm->new_module(Str name)`.
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```cpp
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PyObject* mod = vm->new_module("test");
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mod->attr().set("pi", VAR(3.14));
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mod->attr().set("pi", py_var(vm, 3.14));
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vm->bind_func<2>(mod, "add", [](VM* vm, ArgsView args){
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i64 a = CAST(i64, args[0]);
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i64 b = CAST(i64, args[1]);
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return VAR(a + b);
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});
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vm->bind(mod, "add(a: int, b: int)",
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[](VM* vm, ArgsView args){
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int a = py_cast<int>(vm, args[0]);
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int b = py_cast<int>(vm, args[1]);
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return py_var(vm, a + b);
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});
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```
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```python
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