互通三件套
rust侧与python互通的三个库:
pyo3
pythonize
serde
pyo3
pyo3跟用Python C API写python扩展有点类似,核心是:
#[pymodule]
#[pyfunction]
两个注解。前者对应Py_InitModule,后者对应PyMethodDef。
下面是其它博客上一个python C API写扩展的例子:
//Python.h has all the required function definitions to manipulate the Python objects
#include <Python.h>//This is the function that is called from your python code
static PyObject* addList_add(PyObject* self, PyObject* args){PyObject * listObj;//The input arguments come as a tuple, we parse the args to get the various variables//In this case it's only one list variable, which will now be referenced by listObjif (! PyArg_ParseTuple( args, "O", &listObj ))return NULL;//length of the listlong length = PyList_Size(listObj);//iterate over all the elementsint i, sum =0;for (i = 0; i < length; i++) {//get an element out of the list - the element is also a python objectsPyObject* temp = PyList_GetItem(listObj, i);//we know that object represents an integer - so convert it into C longlong elem = PyInt_AsLong(temp);sum += elem;}//value returned back to python code - another python object//build value here converts the C long to a python integerreturn Py_BuildValue("i", sum);}//This is the docstring that corresponds to our 'add' function.
static char addList_docs[] =
"add( ): add all elements of the list\n";/* This table contains the relavent info mapping -<function-name in python module>, <actual-function>,<type-of-args the function expects>, <docstring associated with the function>*/
static PyMethodDef addList_funcs[] = {{"add", (PyCFunction)addList_add, METH_VARARGS, addList_docs},{NULL, NULL, 0, NULL}};/*addList is the module name, and this is the initialization block of the module.<desired module name>, <the-info-table>, <module's-docstring>*/
PyMODINIT_FUNC initaddList(void){Py_InitModule3("addList", addList_funcs,"Add all ze lists");}
下面是截取的开源库sqloxide的样例代码:
#[pyfunction]
#[pyo3(text_signature = "(sql, dialect)")]
fn parse_sql(py: Python, sql: String, dialect: String) -> PyResult<PyObject> {let chosen_dialect = dialect_from_str(dialect).unwrap_or_else(|| {println!("The dialect you chose was not recognized, falling back to 'generic'");Box::new(GenericDialect {})});let parse_result = Parser::parse_sql(&*chosen_dialect, &sql);...Ok(output.into())
}#[pymodule]
fn sqloxide(_py: Python, m: &Bound<'_, PyModule>) -> PyResult<()> {m.add_function(wrap_pyfunction!(parse_sql, m)?)?;m.add_function(wrap_pyfunction!(restore_ast, m)?)?;...Ok(())
}
pythonize
pythonnize完成rust数据结构到python数据结构的互转。本质上是一个序列化/反序列化器。序列化的结果是一个json结构,可用常见的json库解析。