From d576804a38dbeba79cb5022410d637a2156fd470 Mon Sep 17 00:00:00 2001
From: Bas Schoenmaeckers <b.schoenmaeckers@zandersgroup.com>
Date: Thu, 21 May 2026 08:34:07 +0200
Subject: [PATCH] Add float support to c-api

---
 crates/capi/src/floatobject.rs | 41 ++++++++++++++++++++++++++++++++++
 crates/capi/src/lib.rs         |  1 +
 2 files changed, 42 insertions(+)
 create mode 100644 crates/capi/src/floatobject.rs

diff --git a/crates/capi/src/floatobject.rs b/crates/capi/src/floatobject.rs
new file mode 100644
index 0000000000..f1bb078106
--- /dev/null
+++ b/crates/capi/src/floatobject.rs
@@ -0,0 +1,41 @@
+use crate::object::define_py_check;
+use crate::{PyObject, pystate::with_vm};
+use core::ffi::c_double;
+use rustpython_vm::builtins::PyFloat;
+
+define_py_check!(fn PyFloat_Check, types.float_type);
+define_py_check!(exact fn PyFloat_CheckExact, types.float_type);
+
+#[unsafe(no_mangle)]
+pub extern "C" fn PyFloat_FromDouble(value: c_double) -> *mut PyObject {
+    with_vm(|vm| vm.ctx.new_float(value))
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyFloat_AsDouble(obj: *mut PyObject) -> c_double {
+    with_vm(|vm| {
+        let obj_ref = unsafe { &*obj };
+        let float_obj = obj_ref
+            .to_owned()
+            .try_downcast::<PyFloat>(vm)
+            .or_else(|_| obj_ref.try_float(vm))?;
+
+        Ok(float_obj.to_f64())
+    })
+}
+
+#[cfg(false)]
+mod tests {
+    use core::f64::consts::PI;
+    use pyo3::prelude::*;
+    use pyo3::types::PyFloat;
+
+    #[test]
+    fn test_py_float() {
+        Python::attach(|py| {
+            let pi = PyFloat::new(py, PI);
+            assert!(pi.is_instance_of::<PyFloat>());
+            assert_eq!(pi.extract::<f64>().unwrap(), PI);
+        })
+    }
+}
diff --git a/crates/capi/src/lib.rs b/crates/capi/src/lib.rs
index baa4ddc6b7..6b2745d153 100644
--- a/crates/capi/src/lib.rs
+++ b/crates/capi/src/lib.rs
@@ -13,6 +13,7 @@ pub mod boolobject;
 pub mod bytesobject;
 pub mod ceval;
 pub mod dictobject;
+pub mod floatobject;
 pub mod import;
 pub mod longobject;
 pub mod object;