2024-04-24 16:17:07 +08:00

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---
icon: dot
label: 'Create Modules'
order: 50
---
Modules are stored in `vm->_modules` and `vm->_lazy_modules`.
They are both dict-like objects.
### Lazy modules
A lazy module is a python source file.
It is compiled and executed when it is imported.
Use `[]` operator to add a lazy module.
```cpp
vm->_lazy_modules["test"] = "pi = 3.14";
```
```python
import test
print(test.pi) # 3.14
```
### Native modules
A native module is a module written in c++ or mixed c++/python.
Native modules are always compiled and executed when the VM is created.
To creata a native module, use `vm->new_module(Str name)`.
```cpp
PyObject* mod = vm->new_module("test");
mod->attr().set("pi", py_var(vm, 3.14));
vm->bind(mod, "add(a: int, b: int)",
[](VM* vm, ArgsView args){
int a = py_cast<int>(vm, args[0]);
int b = py_cast<int>(vm, args[1]);
return py_var(vm, a + b);
});
```
```python
import test
print(test.pi) # 3.14
print(test.add(1, 2)) # 3
```
### Module resolution order
When you do `import` a module, the VM will try to find it in the following order:
1. Search `vm->_modules`, if found, return it.
2. Search `vm->_lazy_modules`, if found, compile and execute it, then return it.
3. Try `vm->_import_handler`.
### Customized import handler
You can use `vm->_import_handler` to provide a custom import handler for the 3rd step.
### Import module via cpp
You can use `vm->py_import` to import a module.
This is equivalent to `import` in python.
Return the module object if success.