|
|
@@ -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));
|
|
|
+});
|
|
|
+```
|