This commit is contained in:
BLUELOVETH 2023-05-29 14:27:54 +08:00
parent 59c6252503
commit b9e2a9450c
2 changed files with 80 additions and 6 deletions

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@ -0,0 +1,80 @@
---
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(...)`.
```cpp
PyObject* mod = vm->new_module("test");
mod->attr().set("pi", VAR(3.14));
vm->bind_func<2>(mod, "add", [](VM* vm, ArgsView args){
i64 a = CAST(i64, args[0]);
i64 b = CAST(i64, args[1]);
return VAR(a + b);
});
```
```python
import test
print(test.pi) # 3.14
print(test.add(1, 2)) # 3
```
### Module resolution
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. Search `vm->_path` and try to load it from file system.
### Filesystem hook
You can use `set_read_file_cwd` to provide a custom filesystem hook, which is used for `import` (3rd step).
The default implementation is:
```cpp
set_read_file_cwd([](const Str& name){
std::filesystem::path path(name.sv());
bool exists = std::filesystem::exists(path);
if(!exists) return Bytes();
std::string cname = name.str();
FILE* fp = fopen(cname.c_str(), "rb");
if(!fp) return Bytes();
fseek(fp, 0, SEEK_END);
std::vector<char> buffer(ftell(fp));
fseek(fp, 0, SEEK_SET);
fread(buffer.data(), 1, buffer.size(), fp);
fclose(fp);
return Bytes(std::move(buffer));
});
```

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@ -67,12 +67,6 @@ struct Vector2 {
Vector2& other = CAST(Vector2&, args[1]); Vector2& other = CAST(Vector2&, args[1]);
return VAR(self.x == other.x && self.y == other.y); return VAR(self.x == other.x && self.y == other.y);
}); });
vm->bind_method<1>(type, "__ne__", [](VM* vm, ArgsView args){
Vector2& self = CAST(Vector2&, args[0]);
Vector2& other = CAST(Vector2&, args[1]);
return VAR(self.x != other.x || self.y != other.y);
});
} }
}; };