Working python interface

src/lib.rs

@@ -1,21 +1,29 @@
-use std::{ffi::CString, fs, path::Path};
-
-#[link(name = "python3.13")]
-extern "C" {
-    fn Py_Initialize();
-    fn PyRun_SimpleString(command: *const i8) -> i32;
-    fn Py_Finalize();
+pub enum FluxValue {
+    Int(i64),
+    Float(f64),
+    Str(String),
+    Null,
+    // later: List(Vec<FluxValue>), Dict(HashMap<String, FluxValue>)
 }
 
-pub fn run_py(path: &Path) {
-    let code = fs::read_to_string(path).expect("Failed to read python script");
+pub trait Serialize {
+    fn serialize(&self) -> FluxValue;
+}
 
-    unsafe {
-        Py_Initialize();
+pub trait Deserialize {
+    fn deserialize(v: FluxValue) -> Self;
+}
 
-        let code = CString::new(code.as_str()).unwrap();
-        PyRun_SimpleString(code.as_ptr());
+pub trait FluxModule {
+    fn init(&self);
+    fn end(&self);
+    fn call(&self, func: &str, args: Vec<&dyn Serialize>) -> FluxValue;
+}
+
+pub mod values;
+pub mod runtime;
+
+pub mod prelude {
+    pub use crate::{FluxModule, Serialize, Deserialize};
+}
 
-        Py_Finalize();
-    }
-}

src/main.rs

@@ -1,6 +1,8 @@
-use std::path::Path;
-use flux_rt::run_py;
+use flux_rt::{runtime::python::PythonModule, prelude::*};
 
 fn main() {
-    run_py(Path::new("bro.py"));
+    let bro = PythonModule("bro.py".to_string());
+    bro.init();
+
+    bro.call("hello", vec![]);
 }

src/runtime/mod.rs

@@ -0,0 +1 @@
+pub mod python;

src/runtime/python.rs

@@ -0,0 +1,113 @@
+use std::{ffi::{CString, c_char}, fs};
+
+    use crate::{FluxModule, FluxValue, Serialize};
+
+    #[link(name = "python3.13")]
+    extern "C" {
+        fn Py_Initialize();
+        fn Py_Finalize();
+
+        fn PyRun_SimpleString(command: *const i8) -> i32;
+
+        fn PyImport_AddModule(name: *const c_char) -> *mut PyObject;
+        fn PyModule_GetDict(module: *mut PyObject) -> *mut PyObject;
+        fn PyDict_GetItemString(dict: *mut PyObject, key: *const c_char) -> *mut PyObject;
+
+        fn PyObject_CallObject(callable: *mut PyObject, args: *mut PyObject) -> *mut PyObject;
+        fn Py_BuildValue(format: *const c_char, ...) -> *mut PyObject;
+
+        fn PyLong_AsLong(obj: *mut PyObject) -> i64;
+    }
+
+    #[repr(C)]
+    pub struct PyObject;
+
+    pub struct PythonModule(pub String);
+
+    impl FluxModule for PythonModule {
+        fn init(&self) {
+            let code = fs::read_to_string(&self.0).expect("Failed to read python script");
+            let code = CString::new(code.as_str()).unwrap();
+
+            unsafe {
+                Py_Initialize();
+                PyRun_SimpleString(code.as_ptr());
+            }
+        }
+
+        fn call(&self, func: &str, args: Vec<&dyn Serialize>) -> FluxValue {
+            use std::ffi::CString;
+
+            unsafe {
+                // 1. Get __main__ module dict
+                let main_str = CString::new("__main__").unwrap();
+                let module = PyImport_AddModule(main_str.as_ptr());
+                let dict = PyModule_GetDict(module);
+
+                // 2. Get function by name
+                let func_name = CString::new(func).unwrap();
+                let func_obj = PyDict_GetItemString(dict, func_name.as_ptr());
+
+                if func_obj.is_null() {
+                    panic!("Python function '{}' not found", func);
+                }
+
+                let mut fmt = String::from("(");
+                let values: Vec<FluxValue> = args.iter().map(|a| a.serialize()).collect();
+
+                for v in &values {
+                    match v {
+                        FluxValue::Int(_) => fmt.push('l'),   // long
+                        FluxValue::Float(_) => fmt.push('d'), // double
+                        FluxValue::Str(_) => fmt.push('s'),   // string
+                        FluxValue::Null => fmt.push('O'),  // PyObject*
+                    }
+                }
+                fmt.push(')');
+
+                let fmt_c = CString::new(fmt).unwrap();
+
+                // Call Py_BuildValue with the right arguments
+                let args_obj: *mut PyObject = match values.as_slice() {
+                    [FluxValue::Int(a), FluxValue::Int(b)] => {
+                        Py_BuildValue(fmt_c.as_ptr(), *a, *b)
+                    }
+                    [FluxValue::Float(a), FluxValue::Float(b)] => {
+                        Py_BuildValue(fmt_c.as_ptr(), *a, *b)
+                    }
+                    [FluxValue::Str(a), FluxValue::Str(b)] => {
+                        let a_c = CString::new(a.as_str()).unwrap();
+                        let b_c = CString::new(b.as_str()).unwrap();
+                        Py_BuildValue(fmt_c.as_ptr(), a_c.as_ptr(), b_c.as_ptr())
+                    }
+                    [FluxValue::Int(a)] => {
+                        Py_BuildValue(fmt_c.as_ptr(), *a)
+                    }
+                    [FluxValue::Float(a)] => {
+                        Py_BuildValue(fmt_c.as_ptr(), *a)
+                    }
+                    [FluxValue::Str(a)] => {
+                        let a_c = CString::new(a.as_str()).unwrap();
+                        Py_BuildValue(fmt_c.as_ptr(), a_c.as_ptr())
+                    }
+                    _ => std::ptr::null_mut(),
+                };
+
+                let result_obj = PyObject_CallObject(func_obj, args_obj);
+
+                if result_obj.is_null() {
+                    FluxValue::Null
+                } else {
+                    let value = PyLong_AsLong(result_obj);
+                    FluxValue::Int(value)
+                }
+            }
+        }
+
+
+        fn end(&self) {
+            unsafe {
+                Py_Finalize();
+            }
+        }
+    }

src/values.rs

@@ -0,0 +1,25 @@
+use crate::{Deserialize, FluxValue, Serialize};
+
+impl Serialize for i64 {
+    fn serialize(&self) -> FluxValue {
+        FluxValue::Int(*self)
+    }
+}
+impl Serialize for f64 {
+    fn serialize(&self) -> FluxValue {
+        FluxValue::Float(*self)
+    }
+}
+impl Serialize for &str {
+    fn serialize(&self) -> FluxValue {
+        FluxValue::Str(self.to_string())
+    }
+}
+impl Deserialize for i64 {
+    fn deserialize(v: FluxValue) -> Self {
+        match v {
+            FluxValue::Int(i) => i,
+            _ => panic!("Expected Int"),
+        }
+    }
+}