1.5 KiB
| icon | label | order |
|---|---|---|
| code | Bind native function | 60 |
In VM class, there are 4 methods to bind native function.
VM::bind_func<ARGC>VM::bind_builtin_func<ARGC>VM::bind_method<ARGC>VM::bind_static_method<ARGC>
They are all template methods, the template argument is a int number, indicating the argument count. For variadic arguments, use -1. For methods, ARGC do not include self.
!!!
Native functions do not support keyword arguments.
!!!
PkPy uses a universal C function pointer for native functions:
typedef PyObject* (*NativeFuncC)(VM*, ArgsView);
The first argument is the pointer of VM instance.
The second argument is a view of an array. You can use [] operator to get the element. If you have specified ARGC other than -1, the interpreter will ensure args.size() == ARGC. No need to do size check.
The return value is a PyObject*, which should not be nullptr. If there is no return value, return vm->None.
This is an example of binding the input() function to the builtins module.
VM* vm = pkpy_new_vm(true);
vm->bind_builtin_func<0>("input", [](VM* vm, ArgsView args){
static std::string line;
std::getline(std::cin, line);
return VAR(line);
});
// vvv function name
vm->bind_builtin_func<2>("add", [](VM* vm, ArgsView args){
// ^ argument count
i64 lhs = CAST(i64, args[0]);
i64 rhs = CAST(i64, args[1]);
return VAR(lhs + rhs);
});