drop py_class

2017-05-16 23:43:39 -07:00 · 2017-05-16 23:43:39 -07:00 · c9aefd7e5f
parent 34e4d956f1
commit c9aefd7e5f
26 changed files with 618 additions and 4229 deletions
--- a/Cargo.toml
+++ b/Cargo.toml
@ -7,7 +7,6 @@ readme = "README.md"
 keywords = [
    "pyo3",
    "python",
-    "cpython",
 ]
 homepage = "https://github.com/pyo3/pyo3"
 repository = "https://github.com/pyo3/pyo3.git"
--- a/5
+++ b/5
@ -23,10 +23,7 @@ CARGO_FLAGS := --features "$(FEATURES)" --no-default-features

 default: test

-src/py_class/py_class_impl.rs: src/py_class/py_class_impl.py
-	PY=3 python $< >$@
-
-build: src/py_class/py_class_impl.rs
+build:
 	cargo build $(CARGO_FLAGS)

 test: build
--- a/pyo3cls/src/py_class.rs
+++ b/pyo3cls/src/py_class.rs
@ -5,16 +5,36 @@ use quote::{Tokens, ToTokens};


 pub fn build_py_class(ast: &mut syn::DeriveInput) -> Tokens {
-    if let syn::Body::Enum(_) = ast.body {
-        panic!("#[py_class] can only be used with structs")
-    }
+    let base = syn::Ident::from("pyo3::PyObject");

    let mut tokens = Tokens::new();
+
+    match ast.body {
+        syn::Body::Struct(syn::VariantData::Struct(ref mut data)) => {
+            impl_storage(&ast.ident, &base, data).to_tokens(&mut tokens);
+
+            let tt = quote! {
+                struct Test {
+                    _unsafe_inner: PyObject
+                }
+            };
+            let t = syn::parse_item(tt.as_str()).unwrap();
+            match t.node {
+                syn::ItemKind::Struct(syn::VariantData::Struct(fields), _) => {
+                    data.clear();
+                    data.extend(fields);
+                }
+                _ => panic!("something is worng"),
+            }
+        },
+        _ =>
+            panic!("#[class] can only be used with notmal structs"),
+    }
+
    impl_to_py_object(&ast.ident).to_tokens(&mut tokens);
    impl_from_py_object(&ast.ident).to_tokens(&mut tokens);
    impl_python_object(&ast.ident).to_tokens(&mut tokens);
    impl_checked_downcast(&ast.ident).to_tokens(&mut tokens);
-    impl_class_init(&ast.ident).to_tokens(&mut tokens);

    let dummy_const = syn::Ident::new(format!("_IMPL_PYO3_CLS_{}", ast.ident));
    quote! {
@ -23,13 +43,140 @@ pub fn build_py_class(ast: &mut syn::DeriveInput) -> Tokens {
        const #dummy_const: () = {
            extern crate pyo3;
            use std;
-            use pyo3::ffi;
+            use pyo3::class::BaseObject;
+            use pyo3::{ffi, Python, PyObject, PyType, PyResult, PyModule};

            #tokens
        };
    }
 }

+fn impl_storage(cls: &syn::Ident, base: &syn::Ident, fields: &Vec<syn::Field>) -> Tokens {
+    let names: Vec<syn::Ident> = fields.iter()
+        .map(|f| f.ident.as_ref().unwrap().clone()).collect();
+    let values: Vec<syn::Ident> = fields.iter()
+        .map(|f| f.ident.as_ref().unwrap().clone()).collect();
+    //let types: Vec<syn::Ty> = fields.iter().map(|f| f.ty.clone()).collect();
+
+    let mut accessors = Tokens::new();
+    for field in fields.iter() {
+        let name = &field.ident.as_ref().unwrap();
+        let name_mut = syn::Ident::from(format!("{}_mut", name.as_ref()));
+        let ty = &field.ty;
+
+        let accessor = quote!{
+            impl #cls {
+                fn #name<'a>(&'a self, py: Python<'a>) -> &'a #ty {
+                    unsafe {
+                        let ptr = (self._unsafe_inner.as_ptr() as *const u8)
+                            .offset(base_offset() as isize) as *const Storage;
+                        &(*ptr).#name
+                    }
+                }
+                fn #name_mut<'a>(&'a self, py: Python<'a>) -> &'a mut #ty {
+                    unsafe {
+                        let ptr = (self._unsafe_inner.as_ptr() as *const u8)
+                            .offset(base_offset() as isize) as *mut Storage;
+                        &mut (*ptr).#name
+                    }
+                }
+            }
+        };
+        accessor.to_tokens(&mut accessors);
+    }
+
+    quote! {
+        struct Storage {
+            #(#fields),*
+        }
+
+        impl #cls {
+            fn create_instance(py: Python, #(#fields),*) -> PyResult<#cls> {
+                let obj = try!(unsafe {
+                    <#cls as BaseObject>::alloc(
+                        py, &py.get_type::<#cls>(),
+                        Storage { #(#names: #values),*})});
+
+                return Ok(#cls { _unsafe_inner: obj });
+            }
+        }
+
+        #accessors
+
+        impl pyo3::PythonObjectWithTypeObject for #cls {
+            #[inline]
+            fn type_object(py: Python) -> PyType {
+                unsafe { #cls::initialized(py, None) }
+            }
+        }
+
+        impl pyo3::class::PyTypeObject for #cls {
+
+            fn add_to_module(py: Python, module: &PyModule) -> PyResult<()> {
+                let ty = unsafe { #cls::initialized(py, module.name(py).ok()) };
+                module.add(py, stringify!(#cls), ty)
+            }
+
+            #[inline]
+            unsafe fn type_obj() -> &'static mut ffi::PyTypeObject {
+                static mut TYPE_OBJECT: ffi::PyTypeObject = ffi::PyTypeObject_INIT;
+                &mut TYPE_OBJECT
+            }
+
+            unsafe fn initialized(py: Python, module_name: Option<&str>) -> PyType {
+                let mut ty = #cls::type_obj();
+
+                if (ty.tp_flags & ffi::Py_TPFLAGS_READY) != 0 {
+                    PyType::from_type_ptr(py, ty)
+                } else {
+                    // automatically initialize the class on-demand
+                    pyo3::class::typeob::initialize_type::<#cls>(
+                        py, module_name, ty).expect(
+                        concat!("An error occurred while initializing class ",
+                                stringify!(#cls)));
+                    PyType::from_type_ptr(py, ty)
+                }
+            }
+        }
+
+        #[inline]
+        fn base_offset() -> usize {
+            let align = std::mem::align_of::<Storage>();
+            let bs = <#base as BaseObject>::size();
+
+            // round base_size up to next multiple of align
+            (bs + align - 1) / align * align
+        }
+
+        impl BaseObject for #cls {
+            type Type = Storage;
+
+            #[inline]
+            fn size() -> usize {
+                base_offset() + std::mem::size_of::<Self::Type>()
+            }
+
+            unsafe fn alloc(py: Python, ty: &PyType, value: Self::Type) -> PyResult<PyObject>
+            {
+                let obj = try!(<#base as BaseObject>::alloc(py, ty, ()));
+
+                let ptr = (obj.as_ptr() as *mut u8)
+                    .offset(base_offset() as isize) as *mut Self::Type;
+                std::ptr::write(ptr, value);
+
+                Ok(obj)
+            }
+
+            unsafe fn dealloc(py: Python, obj: *mut ffi::PyObject) {
+                let ptr = (obj as *mut u8).offset(base_offset() as isize) as *mut Self::Type;
+                std::ptr::drop_in_place(ptr);
+
+                <#base as BaseObject>::dealloc(py, obj)
+            }
+        }
+    }
+}
+
 fn impl_to_py_object(cls: &syn::Ident) -> Tokens {
    quote! {
        /// Identity conversion: allows using existing `PyObject` instances where
@ -130,13 +277,3 @@ fn impl_checked_downcast(cls: &syn::Ident) -> Tokens {
        }
    }
 }
-
-fn impl_class_init(cls: &syn::Ident) -> Tokens {
-    quote! {
-        impl pyo3::class::typeob::PyClassInit for #cls {
-            fn init() -> bool {
-                true
-            }
-        }
-    }
-}
--- a/pyo3cls/src/py_method.rs
+++ b/pyo3cls/src/py_method.rs
@ -220,8 +220,8 @@ fn impl_wrap(cls: &Box<syn::Ty>, name: &syn::Ident, args: Vec<Arg>) -> Tokens {
        {
            const LOCATION: &'static str = concat!(
                stringify!(#cls), ".", stringify!(#name), "()");
-            pyo3::_detail::handle_callback(
-                LOCATION, pyo3::_detail::PyObjectCallbackConverter, |py|
+            pyo3::callback::handle_callback(
+                LOCATION, pyo3::callback::PyObjectCallbackConverter, |py|
                {
                    let args: pyo3::PyTuple =
                        pyo3::PyObject::from_borrowed_ptr(py, args).unchecked_cast_into();
@ -248,8 +248,8 @@ fn impl_wrap_getter(cls: &Box<syn::Ty>, name: &syn::Ident, _args: Vec<Arg>) -> T
        {
            const LOCATION: &'static str = concat!(
                stringify!(#cls), ".getter_", stringify!(#name), "()");
-            pyo3::_detail::handle_callback(
-                LOCATION, pyo3::_detail::PyObjectCallbackConverter, |py|
+            pyo3::callback::handle_callback(
+                LOCATION, pyo3::callback::PyObjectCallbackConverter, |py|
                {
                    let slf = pyo3::PyObject::from_borrowed_ptr(
                        py, slf).unchecked_cast_into::<#cls>();
@ -270,8 +270,8 @@ fn impl_wrap_setter(cls: &Box<syn::Ty>, name: &syn::Ident, _args: Vec<Arg>) -> T
        {
            const LOCATION: &'static str = concat!(
                stringify!(#cls), ".setter", stringify!(#name), "()");
-            pyo3::_detail::handle_callback(
-                LOCATION, pyo3::py_class::slots::UnitCallbackConverter, |py|
+            pyo3::callback::handle_callback(
+                LOCATION, pyo3::callback::UnitCallbackConverter, |py|
                {
                    let slf = pyo3::PyObject::from_borrowed_ptr(py, slf)
                        .unchecked_cast_into::<#cls>();
--- a/src/callback.rs
+++ b/src/callback.rs
@ -0,0 +1,242 @@
+/// Utilities for a Python callable object that invokes a Rust function.
+
+use std::os::raw::c_int;
+use std::{any, mem, ptr, isize, io, marker, panic};
+
+use libc;
+use python::{Python, PythonObject};
+use objects::exc;
+use conversion::ToPyObject;
+use ffi::{self, Py_hash_t};
+use err::{PyErr, PyResult};
+
+
+pub trait CallbackConverter<S> {
+    type R;
+
+    fn convert(S, Python) -> Self::R;
+    fn error_value() -> Self::R;
+}
+
+pub struct PyObjectCallbackConverter;
+
+impl <S> CallbackConverter<S> for PyObjectCallbackConverter
+    where S: ToPyObject
+{
+    type R = *mut ffi::PyObject;
+
+    fn convert(val: S, py: Python) -> *mut ffi::PyObject {
+        val.into_py_object(py).into_object().steal_ptr()
+    }
+
+    #[inline]
+    fn error_value() -> *mut ffi::PyObject {
+        ptr::null_mut()
+    }
+}
+
+pub struct PythonObjectCallbackConverter<T>(pub marker::PhantomData<T>);
+
+impl <T, S> CallbackConverter<S> for PythonObjectCallbackConverter<T>
+    where T: PythonObject,
+          S: ToPyObject
+{
+    type R = *mut ffi::PyObject;
+
+    fn convert(val: S, py: Python) -> *mut ffi::PyObject {
+        val.into_py_object(py).into_object().steal_ptr()
+    }
+
+    #[inline]
+    fn error_value() -> *mut ffi::PyObject {
+        ptr::null_mut()
+    }
+}
+
+pub struct BoolConverter;
+
+impl CallbackConverter<bool> for BoolConverter {
+    type R = c_int;
+
+    #[inline]
+    fn convert(val: bool, _py: Python) -> c_int {
+        val as c_int
+    }
+
+    #[inline]
+    fn error_value() -> c_int {
+        -1
+    }
+}
+
+pub struct LenResultConverter;
+
+impl CallbackConverter<usize> for LenResultConverter {
+    type R = isize;
+
+    fn convert(val: usize, py: Python) -> isize {
+        if val <= (isize::MAX as usize) {
+            val as isize
+        } else {
+            PyErr::new_lazy_init(py.get_type::<exc::OverflowError>(), None).restore(py);
+            -1
+        }
+    }
+
+    #[inline]
+    fn error_value() -> isize {
+        -1
+    }
+}
+
+
+pub struct UnitCallbackConverter;
+
+impl CallbackConverter<()> for UnitCallbackConverter {
+    type R = c_int;
+
+    #[inline]
+    fn convert(_: (), _: Python) -> c_int {
+        0
+    }
+
+    #[inline]
+    fn error_value() -> c_int {
+        -1
+    }
+}
+
+pub struct VoidCallbackConverter;
+
+impl CallbackConverter<()> for VoidCallbackConverter {
+    type R = ();
+
+    #[inline]
+    fn convert(_: (), _: Python) -> () {
+        ()
+    }
+
+    #[inline]
+    fn error_value() -> () {
+        ()
+    }
+}
+
+pub struct IterNextResultConverter;
+
+impl <T> CallbackConverter<Option<T>>
+    for IterNextResultConverter
+    where T: ToPyObject
+{
+    type R = *mut ffi::PyObject;
+
+    fn convert(val: Option<T>, py: Python) -> *mut ffi::PyObject {
+        match val {
+            Some(val) => val.into_py_object(py).into_object().steal_ptr(),
+            None => unsafe {
+                ffi::PyErr_SetNone(ffi::PyExc_StopIteration);
+                ptr::null_mut()
+            }
+        }
+    }
+
+    #[inline]
+    fn error_value() -> *mut ffi::PyObject {
+        ptr::null_mut()
+    }
+}
+
+pub trait WrappingCastTo<T> {
+    fn wrapping_cast(self) -> T;
+}
+
+macro_rules! wrapping_cast {
+    ($from:ty, $to:ty) => {
+        impl WrappingCastTo<$to> for $from {
+            #[inline]
+            fn wrapping_cast(self) -> $to {
+                self as $to
+            }
+        }
+    }
+}
+wrapping_cast!(u8, Py_hash_t);
+wrapping_cast!(u16, Py_hash_t);
+wrapping_cast!(u32, Py_hash_t);
+wrapping_cast!(usize, Py_hash_t);
+wrapping_cast!(u64, Py_hash_t);
+wrapping_cast!(i8, Py_hash_t);
+wrapping_cast!(i16, Py_hash_t);
+wrapping_cast!(i32, Py_hash_t);
+wrapping_cast!(isize, Py_hash_t);
+wrapping_cast!(i64, Py_hash_t);
+
+pub struct HashConverter;
+
+impl <T> CallbackConverter<T> for HashConverter
+    where T: WrappingCastTo<Py_hash_t>
+{
+    type R = Py_hash_t;
+
+    #[inline]
+    fn convert(val: T, _py: Python) -> Py_hash_t {
+        let hash = val.wrapping_cast();
+        if hash == -1 {
+            -2
+        } else {
+            hash
+        }
+    }
+
+    #[inline]
+    fn error_value() -> Py_hash_t {
+        -1
+    }
+}
+
+
+pub unsafe fn handle_callback<F, T, C>(location: &str, _c: C, f: F) -> C::R
+    where F: FnOnce(Python) -> PyResult<T>,
+          F: panic::UnwindSafe,
+          C: CallbackConverter<T>
+{
+    let guard = AbortOnDrop(location);
+    let ret = panic::catch_unwind(|| {
+        let py = Python::assume_gil_acquired();
+        match f(py) {
+            Ok(val) => {
+                C::convert(val, py)
+            }
+            Err(e) => {
+                e.restore(py);
+                C::error_value()
+            }
+        }
+    });
+    let ret = match ret {
+        Ok(r) => r,
+        Err(ref err) => {
+            handle_panic(Python::assume_gil_acquired(), err);
+            C::error_value()
+        }
+    };
+    mem::forget(guard);
+    ret
+}
+
+fn handle_panic(_py: Python, _panic: &any::Any) {
+    let msg = cstr!("Rust panic");
+    unsafe {
+        ffi::PyErr_SetString(ffi::PyExc_SystemError, msg.as_ptr());
+    }
+}
+
+pub struct AbortOnDrop<'a>(pub &'a str);
+
+impl <'a> Drop for AbortOnDrop<'a> {
+    fn drop(&mut self) {
+        use std::io::Write;
+        let _ = writeln!(&mut io::stderr(), "Cannot unwind out of {}", self.0);
+        unsafe { libc::abort() }
+    }
+}
--- a/src/class/async.rs
+++ b/src/class/async.rs
@ -10,7 +10,7 @@ use ffi;
 use err::PyResult;
 use python::{Python, PythonObject};
 use objects::PyObject;
-use function::PyObjectCallbackConverter;
+use callback::PyObjectCallbackConverter;
 use class::NO_METHODS;


--- a/src/class/basic.rs
+++ b/src/class/basic.rs
@ -11,10 +11,9 @@ use ::{CompareOp, Py_hash_t};
 use ffi;
 use err::{PyErr, PyResult};
 use python::{Python, PythonObject, PyDrop};
-use conversion::ToPyObject;
 use objects::{exc, PyObject};
-use py_class::slots::{HashConverter, UnitCallbackConverter};
-use function::{handle_callback, PyObjectCallbackConverter};
+use conversion::ToPyObject;
+use callback::{handle_callback, PyObjectCallbackConverter, HashConverter, UnitCallbackConverter};
 use class::{NO_METHODS, NO_PY_METHODS};

 // __new__
--- a/src/class/buffer.rs
+++ b/src/class/buffer.rs
@ -11,8 +11,7 @@ use ffi;
 use err::PyResult;
 use python::{Python, PythonObject};
 use objects::PyObject;
-use py_class::slots::UnitCallbackConverter;
-use function::handle_callback;
+use callback::{handle_callback, UnitCallbackConverter};
 use class::NO_METHODS;


--- a/src/class/descr.rs
+++ b/src/class/descr.rs
@ -12,8 +12,7 @@ use err::{PyErr, PyResult};
 use python::{Python, PythonObject};
 use objects::{exc, PyObject};
 use class::{NO_METHODS, NO_PY_METHODS};
-use function::PyObjectCallbackConverter;
-use py_class::slots::UnitCallbackConverter;
+use callback::{PyObjectCallbackConverter, UnitCallbackConverter};

 /// Descriptor interface
 pub trait PyDescrProtocol {
--- a/src/class/gc.rs
+++ b/src/class/gc.rs
@ -9,7 +9,7 @@ use std::os::raw::{c_int, c_void};
 use ffi;
 use python::{Python, PythonObject, PyDrop, ToPythonPointer};
 use objects::PyObject;
-use function::AbortOnDrop;
+use callback::AbortOnDrop;
 use class::NO_METHODS;

 pub struct PyTraverseError(c_int);
--- a/src/class/macros.rs
+++ b/src/class/macros.rs
@ -11,7 +11,7 @@ macro_rules! py_unary_func {
            where T: $trait + PythonObject
        {
            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(LOCATION, $conv, |py| {
+            $crate::callback::handle_callback(LOCATION, $conv, |py| {
                let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<T>();
                let ret = slf.$f(py);
                $crate::PyDrop::release_ref(slf, py);
@ -31,7 +31,7 @@ macro_rules! py_unary_func {
            where T: $trait + PythonObject
        {
            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(LOCATION, $conv, |py| {
+            $crate::callback::handle_callback(LOCATION, $conv, |py| {
                let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<T>();
                let ret = slf.$f(py);
                $crate::PyDrop::release_ref(slf, py);
@ -52,7 +52,7 @@ macro_rules! py_binary_func {
            where T: $trait + PythonObject
        {
            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(LOCATION, $conv, |py| {
+            $crate::callback::handle_callback(LOCATION, $conv, |py| {
                let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<T>();
                let arg = $crate::PyObject::from_borrowed_ptr(py, arg);
                let ret = slf.$f(py, &arg);
@ -78,7 +78,7 @@ macro_rules! py_ternary_func {
            where T: $trait + PythonObject
        {
            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(LOCATION, $conv, |py| {
+            $crate::callback::handle_callback(LOCATION, $conv, |py| {
                let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<T>();
                let arg1 = $crate::PyObject::from_borrowed_ptr(py, arg1);
                let arg2 = $crate::PyObject::from_borrowed_ptr(py, arg2);
@ -102,7 +102,7 @@ macro_rules! py_ssizearg_func {
            where T: $trait + PythonObject
        {
            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(LOCATION, $conv, |py| {
+            $crate::callback::handle_callback(LOCATION, $conv, |py| {
                let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<T>();
                let ret = slf.$f(py, arg as isize);
                $crate::PyDrop::release_ref(slf, py);
@ -123,7 +123,7 @@ macro_rules! py_objobj_proc {
            where T: $trait + PythonObject
        {
            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(LOCATION, $conv, |py| {
+            $crate::callback::handle_callback(LOCATION, $conv, |py| {
                let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<T>();
                let arg = PyObject::from_borrowed_ptr(py, arg);
                let ret = slf.$f(py, &arg);
@ -148,7 +148,7 @@ macro_rules! py_ternary_slot {
            where T: $trait + PythonObject
        {
            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
+            $crate::callback::handle_callback(
                LOCATION, $conv, |py|
                {
                    let slf = $crate::PyObject::from_borrowed_ptr(
--- a/src/class/mapping.rs
+++ b/src/class/mapping.rs
@ -9,8 +9,8 @@ use ffi;
 use err::{PyErr, PyResult};
 use python::{Python, PythonObject, PyDrop};
 use objects::{exc, PyObject};
-use py_class::slots::{LenResultConverter, UnitCallbackConverter};
-use function::{handle_callback, PyObjectCallbackConverter};
+use callback::{handle_callback, PyObjectCallbackConverter,
+               LenResultConverter, UnitCallbackConverter};
 use class::NO_METHODS;


--- a/src/class/mod.rs
+++ b/src/class/mod.rs
@ -1,5 +1,8 @@
 // Copyright (c) 2017-present PyO3 Project and Contributors

+use std::mem;
+use std::os::raw::c_void;
+
 #[macro_use] mod macros;

 pub mod async;
@ -23,9 +26,77 @@ pub use self::number::PyNumberProtocol;
 pub use self::mapping::PyMappingProtocol;
 pub use self::sequence::PySequenceProtocol;

+pub use self::typeob::PyTypeObject;
 pub use self::gc::{PyVisit, PyGCProtocol, PyTraverseError};
 pub use self::methods::{PyMethodDef, PyMethodDefType, PyMethodType,
                        PyGetterDef, PySetterDef};

 pub static NO_METHODS: &'static [&'static str] = &[];
 pub static NO_PY_METHODS: &'static [PyMethodDefType] = &[];
+
+use ffi;
+use err::{self, PyResult};
+use objects::{PyObject, PyType};
+use python::{Python, PythonObject};
+
+
+#[derive(Debug)]
+pub enum CompareOp {
+    Lt = ffi::Py_LT as isize,
+    Le = ffi::Py_LE as isize,
+    Eq = ffi::Py_EQ as isize,
+    Ne = ffi::Py_NE as isize,
+    Gt = ffi::Py_GT as isize,
+    Ge = ffi::Py_GE as isize
+}
+
+
+/// A PythonObject that is usable as a base type for #[class]
+pub trait BaseObject : PythonObject {
+    /// Gets the size of the object, in bytes.
+    fn size() -> usize;
+
+    type Type;
+
+    /// Allocates a new object (usually by calling ty->tp_alloc),
+    /// and initializes it using init_val.
+    /// `ty` must be derived from the Self type, and the resulting object
+    /// must be of type `ty`.
+    unsafe fn alloc(py: Python, ty: &PyType, val: Self::Type) -> PyResult<PyObject>;
+
+    /// Calls the rust destructor for the object and frees the memory
+    /// (usually by calling ptr->ob_type->tp_free).
+    /// This function is used as tp_dealloc implementation.
+    unsafe fn dealloc(py: Python, obj: *mut ffi::PyObject);
+}
+
+
+impl BaseObject for PyObject {
+    #[inline]
+    fn size() -> usize {
+        mem::size_of::<ffi::PyObject>()
+    }
+
+    type Type = ();
+
+    unsafe fn alloc(py: Python, ty: &PyType, _init_val: ()) -> PyResult<PyObject> {
+        let ptr = ffi::PyType_GenericAlloc(ty.as_type_ptr(), 0);
+        err::result_from_owned_ptr(py, ptr)
+    }
+
+    unsafe fn dealloc(_py: Python, obj: *mut ffi::PyObject) {
+        // Unfortunately, there is no PyType_GenericFree, so
+        // we have to manually un-do the work of PyType_GenericAlloc:
+        let ty = ffi::Py_TYPE(obj);
+        if ffi::PyType_IS_GC(ty) != 0 {
+            ffi::PyObject_GC_Del(obj as *mut c_void);
+        } else {
+            ffi::PyObject_Free(obj as *mut c_void);
+        }
+        // For heap types, PyType_GenericAlloc calls INCREF on the type objects,
+        // so we need to call DECREF here:
+        if ffi::PyType_HasFeature(ty, ffi::Py_TPFLAGS_HEAPTYPE) != 0 {
+            ffi::Py_DECREF(ty as *mut ffi::PyObject);
+        }
+    }
+}
--- a/src/class/number.rs
+++ b/src/class/number.rs
@ -9,8 +9,7 @@ use ffi;
 use err::PyResult;
 use python::{Python, PythonObject};
 use objects::PyObject;
-use function::PyObjectCallbackConverter;
-use py_class::slots::BoolConverter;
+use callback::{BoolConverter, PyObjectCallbackConverter};
 use class::{NO_METHODS, NO_PY_METHODS};
 use class::basic::{PyObjectProtocol, PyObjectProtocolImpl};

--- a/src/class/sequence.rs
+++ b/src/class/sequence.rs
@ -9,8 +9,8 @@ use ffi;
 use err::{PyErr, PyResult};
 use python::{Python, PythonObject, PyDrop};
 use objects::{exc, PyObject};
-use py_class::slots::{LenResultConverter, UnitCallbackConverter, BoolConverter};
-use function::{handle_callback, PyObjectCallbackConverter};
+use callback::{handle_callback, PyObjectCallbackConverter,
+               LenResultConverter, UnitCallbackConverter, BoolConverter};
 use class::NO_METHODS;


--- a/src/class/typeob.rs
+++ b/src/class/typeob.rs
@ -4,38 +4,26 @@ use std::mem;
 use std::ffi::CString;
 use std::collections::HashMap;

-use ::{ffi, class, py_class, PyErr, Python, PyResult, PythonObject};
-use objects::PyType;
-use function::AbortOnDrop;
-use class::PyMethodDefType;
+use ::{ffi, class, PyErr, Python, PyResult, PythonObject};
+use objects::{PyType, PyModule};
+use callback::AbortOnDrop;
+use class::{BaseObject, PyMethodDefType};


-pub trait PyClassInit {
+pub trait PyTypeObject : BaseObject + PythonObject {

-    fn init() -> bool;
+    fn add_to_module(py: Python, module: &PyModule) -> PyResult<()>;

-    fn type_object() -> &'static mut ffi::PyTypeObject;
+    unsafe fn type_obj() -> &'static mut ffi::PyTypeObject;

-    fn build_type(py: Python,
-                  module_name: Option<&str>,
-                  type_object: &mut ffi::PyTypeObject) -> PyResult<PyType>;
+    unsafe fn initialized(py: Python, module_name: Option<&str>) -> PyType;

 }

-impl<T> PyClassInit for T
-    where T: PythonObject + py_class::BaseObject {
-
-    default fn init() -> bool { false }
-
-    default fn type_object() -> &'static mut ffi::PyTypeObject {
-        static mut TYPE_OBJECT: ffi::PyTypeObject = ffi::PyTypeObject_INIT;
-        unsafe {
-            &mut TYPE_OBJECT
-        }
-    }
-
-    default fn build_type(py: Python, module_name: Option<&str>,
-                          type_object: &mut ffi::PyTypeObject) -> PyResult<PyType> {
+pub fn initialize_type<T>(py: Python, module_name: Option<&str>,
+                          type_object: &mut ffi::PyTypeObject) -> PyResult<PyType>
+    where T: BaseObject + PythonObject
+{
    // type name
    let name = match module_name {
        Some(module_name) => CString::new(
@ -54,7 +42,7 @@ impl<T> PyClassInit for T
    <T as class::gc::PyGCProtocolImpl>::update_type_object(type_object);

    // type size
-        type_object.tp_basicsize = <T as py_class::BaseObject>::size() as ffi::Py_ssize_t;
+    type_object.tp_basicsize = <T as BaseObject>::size() as ffi::Py_ssize_t;

    // descriptor protocol
    type_object.tp_descr_get = class::descr::get_descrfunc::<T>();
@ -137,11 +125,9 @@ impl<T> PyClassInit for T
            Err(PyErr::fetch(py))
        }
    }
-    }
 }

-pub unsafe extern "C" fn tp_dealloc_callback<T>(obj: *mut ffi::PyObject)
-    where T: py_class::BaseObject
+unsafe extern "C" fn tp_dealloc_callback<T>(obj: *mut ffi::PyObject) where T: BaseObject
 {
    let guard = AbortOnDrop("Cannot unwind out of tp_dealloc");
    let py = Python::assume_gil_acquired();
--- a/src/err.rs
+++ b/src/err.rs
@ -100,7 +100,7 @@ macro_rules! py_exception {
            #[inline]
            fn type_object(py: $crate::Python) -> $crate::PyType {
                unsafe {
-                    static mut type_object: *mut $crate::_detail::ffi::PyTypeObject = 0 as *mut $crate::_detail::ffi::PyTypeObject;
+                    static mut type_object: *mut $crate::ffi::PyTypeObject = 0 as *mut $crate::ffi::PyTypeObject;

                    if type_object.is_null() {
                        type_object = $crate::PyErr::new_type(
--- a/src/function.rs
+++ b/src/function.rs
@ -16,30 +16,27 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.

-use libc;
-use std::{mem, ptr, io, any, marker};
-use std::panic;
-use python::{Python, PythonObject};
+use std::ptr;
+use python::Python;
 use objects::PyObject;
-use conversion::ToPyObject;
 use ffi;
-use err::{self, PyResult};
+use err;

 #[macro_export]
 #[doc(hidden)]
 macro_rules! py_method_def {
    ($name: expr, $flags: expr, $wrap: expr) => {{
-        static mut METHOD_DEF: $crate::_detail::ffi::PyMethodDef = $crate::_detail::ffi::PyMethodDef {
+        static mut METHOD_DEF: $crate::ffi::PyMethodDef = $crate::ffi::PyMethodDef {
            //ml_name: bytes!(stringify!($name), "\0"),
-            ml_name: 0 as *const $crate::_detail::libc::c_char,
+            ml_name: 0 as *const $crate::c_char,
            ml_meth: None,
-            ml_flags: $crate::_detail::ffi::METH_VARARGS | $crate::_detail::ffi::METH_KEYWORDS | $flags,
-            ml_doc: 0 as *const $crate::_detail::libc::c_char
+            ml_flags: $crate::ffi::METH_VARARGS | $crate:::METH_KEYWORDS | $flags,
+            ml_doc: 0 as *const $crate::c_char
        };
        METHOD_DEF.ml_name = concat!($name, "\0").as_ptr() as *const _;
        METHOD_DEF.ml_meth = Some(
-            ::std::mem::transmute::<$crate::_detail::ffi::PyCFunctionWithKeywords,
-                                  $crate::_detail::ffi::PyCFunction>($wrap)
+            ::std::mem::transmute::<$crate::ffi::PyCFunctionWithKeywords,
+                                  $crate::ffi::PyCFunction>($wrap)
        );
        &mut METHOD_DEF
    }}
@ -112,13 +109,13 @@ macro_rules! py_fn_impl {
    // Form 1: reference existing function
    { $py:expr, $f:ident [ $( { $pname:ident : $ptype:ty = $detail:tt } )* ] } => {{
        unsafe extern "C" fn wrap(
-            _slf: *mut $crate::_detail::ffi::PyObject,
-            args: *mut $crate::_detail::ffi::PyObject,
-            kwargs: *mut $crate::_detail::ffi::PyObject)
-        -> *mut $crate::_detail::ffi::PyObject
+            _slf: *mut $crate::ffi::PyObject,
+            args: *mut $crate::ffi::PyObject,
+            kwargs: *mut $crate::ffi::PyObject)
+        -> *mut $crate::ffi::PyObject
        {
-            $crate::_detail::handle_callback(
-                stringify!($f), $crate::_detail::PyObjectCallbackConverter,
+            $crate::callback::handle_callback(
+                stringify!($f), $crate::callback::PyObjectCallbackConverter,
                |py| {
                    py_argparse_raw!(py, Some(stringify!($f)), args, kwargs,
                        [ $( { $pname : $ptype = $detail } )* ]
@ -128,7 +125,7 @@ macro_rules! py_fn_impl {
                })
        }
        unsafe {
-            $crate::_detail::py_fn_impl($py,
+            $crate::function::py_fn_impl($py,
                py_method_def!(stringify!($f), 0, wrap))
        }
    }};
@ -139,97 +136,8 @@ macro_rules! py_fn_impl {
    }}
 }

+
+#[allow(dead_code)]
 pub unsafe fn py_fn_impl(py: Python, method_def: *mut ffi::PyMethodDef) -> PyObject {
    err::from_owned_ptr_or_panic(py, ffi::PyCFunction_New(method_def, ptr::null_mut()))
 }
-
-pub trait CallbackConverter<S> {
-    type R;
-
-    fn convert(S, Python) -> Self::R;
-    fn error_value() -> Self::R;
-}
-
-pub struct PyObjectCallbackConverter;
-
-impl <S> CallbackConverter<S> for PyObjectCallbackConverter
-    where S: ToPyObject
-{
-    type R = *mut ffi::PyObject;
-
-    fn convert(val: S, py: Python) -> *mut ffi::PyObject {
-        val.into_py_object(py).into_object().steal_ptr()
-    }
-
-    #[inline]
-    fn error_value() -> *mut ffi::PyObject {
-        ptr::null_mut()
-    }
-}
-
-pub struct PythonObjectCallbackConverter<T>(pub marker::PhantomData<T>);
-
-impl <T, S> CallbackConverter<S> for PythonObjectCallbackConverter<T>
-    where T: PythonObject,
-          S: ToPyObject
-{
-    type R = *mut ffi::PyObject;
-
-    fn convert(val: S, py: Python) -> *mut ffi::PyObject {
-        val.into_py_object(py).into_object().steal_ptr()
-    }
-
-    #[inline]
-    fn error_value() -> *mut ffi::PyObject {
-        ptr::null_mut()
-    }
-}
-
-pub unsafe fn handle_callback<F, T, C>(location: &str, _c: C, f: F) -> C::R
-    where F: FnOnce(Python) -> PyResult<T>,
-          F: panic::UnwindSafe,
-          C: CallbackConverter<T>
-{
-    let guard = AbortOnDrop(location);
-    let ret = panic::catch_unwind(|| {
-        let py = Python::assume_gil_acquired();
-        match f(py) {
-            Ok(val) => {
-                C::convert(val, py)
-            }
-            Err(e) => {
-                e.restore(py);
-                C::error_value()
-            }
-        }
-    });
-    let ret = match ret {
-        Ok(r) => r,
-        Err(ref err) => {
-            handle_panic(Python::assume_gil_acquired(), err);
-            C::error_value()
-        }
-    };
-    mem::forget(guard);
-    ret
-}
-
-fn handle_panic(_py: Python, _panic: &any::Any) {
-    let msg = cstr!("Rust panic");
-    unsafe {
-        ffi::PyErr_SetString(ffi::PyExc_SystemError, msg.as_ptr());
-    }
-}
-
-pub struct AbortOnDrop<'a>(pub &'a str);
-
-impl <'a> Drop for AbortOnDrop<'a> {
-    fn drop(&mut self) {
-        use std::io::Write;
-        let _ = writeln!(&mut io::stderr(), "Cannot unwind out of {}", self.0);
-        unsafe { libc::abort() }
-    }
-}
-
-// Tests for this file are in tests/test_function.rs
-
--- a/src/lib.rs
+++ b/src/lib.rs
@ -96,7 +96,7 @@ pub use objects::*;
 pub use python::{Python, PythonObject, PythonObjectWithCheckedDowncast, PythonObjectDowncastError, PythonObjectWithTypeObject, PyClone, PyDrop};
 pub use pythonrun::{GILGuard, GILProtected, prepare_freethreaded_python};
 pub use conversion::{FromPyObject, RefFromPyObject, ToPyObject, ToPyTuple};
-pub use py_class::{CompareOp};
+pub use class::{CompareOp};
 pub use objectprotocol::{ObjectProtocol};

 #[allow(non_camel_case_types)]
@ -142,7 +142,7 @@ macro_rules! py_impl_to_py_object_for_python_object {

            #[inline]
            fn with_borrowed_ptr<F, R>(&self, _py: $crate::Python, f: F) -> R
-                where F: FnOnce(*mut $crate::_detail::ffi::PyObject) -> R
+                where F: FnOnce(*mut $crate::ffi::PyObject) -> R
            {
                f($crate::PythonObject::as_object(self).as_ptr())
            }
@ -170,7 +170,6 @@ macro_rules! py_impl_from_py_object_for_python_object {
    }
 }

-pub mod py_class;
 mod python;
 mod err;
 mod conversion;
@ -182,24 +181,11 @@ mod function;
 pub mod buffer;
 pub mod class;
 pub use class::*;
+pub mod callback;

 // re-export for simplicity
 pub use std::os::raw::*;

-/// Private re-exports for macros. Do not use.
-#[doc(hidden)]
-pub mod _detail {
-    pub mod ffi {
-        pub use ::ffi::*;
-    }
-    pub mod libc {
-        pub use std::os::raw::{c_char, c_void, c_int};
-    }
-    pub use err::{from_owned_ptr_or_panic, result_from_owned_ptr};
-    pub use function::{handle_callback, py_fn_impl, AbortOnDrop,
-                       PyObjectCallbackConverter, PythonObjectCallbackConverter};
-}
-
 /// Expands to an `extern "C"` function that allows Python to load
 /// the rust code as a Python extension module.
 ///
@ -264,7 +250,7 @@ macro_rules! py_module_init {
            fn init($py_id: $crate::Python, $m_id: &$crate::PyModule) -> $crate::PyResult<()> {
                $body
            }
-            static mut MODULE_DEF: $crate::ffi::PyModuleDef = $crate::_detail::ffi::PyModuleDef_INIT;
+            static mut MODULE_DEF: $crate::ffi::PyModuleDef = $crate::ffi::PyModuleDef_INIT;
            // We can't convert &'static str to *const c_char within a static initializer,
            // so we'll do it here in the module initialization:
            MODULE_DEF.m_name = concat!(stringify!($name), "\0").as_ptr() as *const _;
@ -278,7 +264,7 @@ pub unsafe fn py_module_init_impl(
    def: *mut ffi::PyModuleDef,
    init: fn(Python, &PyModule) -> PyResult<()>) -> *mut ffi::PyObject
 {
-    let guard = function::AbortOnDrop("py_module_init");
+    let guard = callback::AbortOnDrop("py_module_init");
    let py = Python::assume_gil_acquired();
    ffi::PyEval_InitThreads();
    let module = ffi::PyModule_Create(def);
--- a/src/objects/module.rs
+++ b/src/objects/module.rs
@ -23,7 +23,7 @@ use python::{Python, PythonObject};
 use objectprotocol::ObjectProtocol;
 use conversion::{ToPyObject, ToPyTuple};
 use objects::{PyObject, PyDict, exc};
-use py_class::PythonObjectFromPyClassMacro;
+use class::PyTypeObject;
 use err::{self, PyResult, PyErr};
 use std::ffi::{CStr, CString};

@ -107,11 +107,11 @@ impl PyModule {

    /// Adds a new extension type to the module.
    ///
-    /// This is a convenience function that initializes the `py_class!()`,
+    /// This is a convenience function that initializes the `class`,
    /// sets `new_type.__module__` to this module's name,
    /// and adds the type to this module.
    pub fn add_class<'p, T>(&self, py: Python<'p>) -> PyResult<()>
-        where T: PythonObjectFromPyClassMacro
+        where T: PyTypeObject
    {
        T::add_to_module(py, self)
    }
--- a/src/py_class/members.rs
+++ b/src/py_class/members.rs
@ -1,194 +0,0 @@
-// Copyright (c) 2016 Daniel Grunwald
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-use std::marker;
-use python::{Python, PythonObject};
-use conversion::ToPyObject;
-use objects::PyObject;
-use err::{self, PyResult};
-use ffi;
-
-/// Represents something that can be added as a member to a Python class/type.
-///
-/// T: type of rust class used for instances of the Python class/type.
-pub trait TypeMember<T> where T: PythonObject {
-    /// Convert the type member into a python object
-    /// that can be stored in the type dict.
-    ///
-    /// Because the member may expect `self` values to be of type `T`,
-    /// `ty` must be T::type_object() or a derived class.
-    /// (otherwise the behavior is undefined)
-    unsafe fn into_descriptor(self, py: Python, ty: *mut ffi::PyTypeObject) -> PyResult<PyObject>;
-}
-
-impl <T, S> TypeMember<T> for S where T: PythonObject, S: ToPyObject {
-    #[inline]
-    unsafe fn into_descriptor(self, py: Python, _ty: *mut ffi::PyTypeObject) -> PyResult<PyObject> {
-        Ok(self.into_py_object(py).into_object())
-    }
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_init_members {
-    ($class:ident, $py:ident, $type_object: ident, { }) => {{}};
-    ($class:ident, $py:ident, $type_object: ident, { $( $name:ident = $init:expr; )+ }) => {{
-        let dict = $crate::PyDict::new($py);
-        $( {
-            // keep $init out of unsafe block; it might contain user code
-            let init = $init;
-            let descriptor = try!(unsafe {
-                $crate::py_class::members::TypeMember::<$class>::into_descriptor(init, $py, &mut $type_object)
-            });
-            try!(dict.set_item($py, stringify!($name), descriptor));
-        })*
-        unsafe {
-            assert!($type_object.tp_dict.is_null());
-            $type_object.tp_dict = $crate::PythonObject::into_object(dict).steal_ptr();
-        }
-    }};
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_instance_method {
-    ($py:ident, $class:ident :: $f:ident [ $( { $pname:ident : $ptype:ty = $detail:tt } )* ]) => {{
-        unsafe extern "C" fn wrap_instance_method(
-            slf: *mut $crate::_detail::ffi::PyObject,
-            args: *mut $crate::_detail::ffi::PyObject,
-            kwargs: *mut $crate::_detail::ffi::PyObject)
-        -> *mut $crate::_detail::ffi::PyObject
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $crate::_detail::PyObjectCallbackConverter,
-                |py| {
-                    py_argparse_raw!(py, Some(LOCATION), args, kwargs,
-                        [ $( { $pname : $ptype = $detail } )* ]
-                        {
-                            let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                            let ret = slf.$f(py $(, $pname )* );
-                            $crate::PyDrop::release_ref(slf, py);
-                            ret
-                        })
-                })
-        }
-        unsafe {
-            let method_def = py_method_def!(stringify!($f), 0, wrap_instance_method);
-            $crate::py_class::members::create_instance_method_descriptor::<$class>(method_def)
-        }
-    }}
-}
-
-pub struct InstanceMethodDescriptor<T>(*mut ffi::PyMethodDef, marker::PhantomData<fn(&T)>);
-
-#[inline]
-pub unsafe fn create_instance_method_descriptor<T>(method_def: *mut ffi::PyMethodDef)
-  -> InstanceMethodDescriptor<T>
-{
-    InstanceMethodDescriptor(method_def, marker::PhantomData)
-}
-
-impl <T> TypeMember<T> for InstanceMethodDescriptor<T> where T: PythonObject {
-    #[inline]
-    unsafe fn into_descriptor(self, py: Python, ty: *mut ffi::PyTypeObject) -> PyResult<PyObject> {
-        err::result_from_owned_ptr(py, ffi::PyDescr_NewMethod(ty, self.0))
-    }
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_class_method {
-    ($py:ident, $class:ident :: $f:ident [ $( { $pname:ident : $ptype:ty = $detail:tt } )* ]) => {{
-        unsafe extern "C" fn wrap_class_method(
-            cls: *mut $crate::_detail::ffi::PyObject,
-            args: *mut $crate::_detail::ffi::PyObject,
-            kwargs: *mut $crate::_detail::ffi::PyObject)
-        -> *mut $crate::_detail::ffi::PyObject
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $crate::_detail::PyObjectCallbackConverter,
-                |py| {
-                    py_argparse_raw!(py, Some(LOCATION), args, kwargs,
-                        [ $( { $pname : $ptype = $detail } )* ]
-                        {
-                            let cls = $crate::PyObject::from_borrowed_ptr(py, cls).unchecked_cast_into::<$crate::PyType>();
-                            let ret = $class::$f(&cls, py $(, $pname )* );
-                            $crate::PyDrop::release_ref(cls, py);
-                            ret
-                        })
-                })
-        }
-        unsafe {
-            let method_def = py_method_def!(stringify!($f),
-                $crate::_detail::ffi::METH_CLASS,
-                wrap_class_method);
-            $crate::py_class::members::create_class_method_descriptor(method_def)
-        }
-    }}
-}
-
-pub struct ClassMethodDescriptor(*mut ffi::PyMethodDef);
-
-#[inline]
-pub unsafe fn create_class_method_descriptor(method_def: *mut ffi::PyMethodDef)
-  -> ClassMethodDescriptor
-{
-    ClassMethodDescriptor(method_def)
-}
-
-impl <T> TypeMember<T> for ClassMethodDescriptor where T: PythonObject {
-    #[inline]
-    unsafe fn into_descriptor(self, py: Python, ty: *mut ffi::PyTypeObject) -> PyResult<PyObject> {
-        err::result_from_owned_ptr(py, ffi::PyDescr_NewClassMethod(ty, self.0))
-    }
-}
-
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_static_method {
-    ($py:ident, $class:ident :: $f:ident [ $( { $pname:ident : $ptype:ty = $detail:tt } )* ]) => {{
-        unsafe extern "C" fn wrap_static_method(
-            _slf: *mut $crate::_detail::ffi::PyObject,
-            args: *mut $crate::_detail::ffi::PyObject,
-            kwargs: *mut $crate::_detail::ffi::PyObject)
-        -> *mut $crate::_detail::ffi::PyObject
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $crate::_detail::PyObjectCallbackConverter,
-                |py| {
-                    py_argparse_raw!(py, Some(LOCATION), args, kwargs,
-                        [ $( { $pname : $ptype = $detail } )* ]
-                        {
-                            $class::$f(py $(, $pname )* )
-                        })
-                })
-        }
-        unsafe {
-            let method_def = py_method_def!(stringify!($f),
-                $crate::_detail::ffi::METH_STATIC,
-                wrap_static_method);
-            $crate::_detail::py_fn_impl($py, method_def)
-        }
-    }}
-}
-
-
--- a/src/py_class/mod.rs
+++ b/src/py_class/mod.rs
@ -1,148 +0,0 @@
-// Copyright (c) 2016 Daniel Grunwald
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-mod py_class;
-mod py_class_impl;
-#[doc(hidden)] pub mod slots;
-#[doc(hidden)] pub mod members;
-
-use std::os::raw::c_void;
-use std::{mem, ptr};
-use python::{self, Python, PythonObject};
-use objects::{PyObject, PyType, PyModule};
-use err::{self, PyResult};
-use ffi;
-
-// TODO: consider moving CompareOp to a different module, so that it isn't exported via two paths
-#[derive(Debug)]
-pub enum CompareOp {
-    Lt = ffi::Py_LT as isize,
-    Le = ffi::Py_LE as isize,
-    Eq = ffi::Py_EQ as isize,
-    Ne = ffi::Py_NE as isize,
-    Gt = ffi::Py_GT as isize,
-    Ge = ffi::Py_GE as isize
-}
-
-/// Trait implemented by the types produced by the `py_class!()` macro.
-///
-/// This is an unstable implementation detail; do not implement manually!
-pub trait PythonObjectFromPyClassMacro : python::PythonObjectWithTypeObject {
-    /// Initializes the class.
-    ///
-    /// module_name: the name of the parent module into which the class will be placed.
-    fn initialize(py: Python, module_name: Option<&str>) -> PyResult<PyType>;
-
-    /// Initializes the class and adds it to the module.
-    fn add_to_module(py: Python, module: &PyModule) -> PyResult<()>;
-}
-
-#[inline]
-#[doc(hidden)]
-pub fn data_offset<T>(base_size: usize) -> usize {
-    let align = mem::align_of::<T>();
-    // round base_size up to next multiple of align
-    (base_size + align - 1) / align * align
-}
-
-#[inline]
-#[doc(hidden)]
-pub fn data_new_size<T>(base_size: usize) -> usize {
-    data_offset::<T>(base_size) + mem::size_of::<T>()
-}
-
-#[inline]
-#[doc(hidden)]
-pub unsafe fn data_get<'a, T>(_py: Python<'a>, obj: &'a PyObject, offset: usize) -> &'a T {
-    let ptr = (obj.as_ptr() as *const u8).offset(offset as isize) as *const T;
-    &*ptr
-}
-
-#[inline]
-#[doc(hidden)]
-pub unsafe fn data_init<'a, T>(_py: Python<'a>, obj: &'a PyObject, offset: usize, value: T)
-    where T: Send + 'static
-{
-    let ptr = (obj.as_ptr() as *mut u8).offset(offset as isize) as *mut T;
-    ptr::write(ptr, value)
-}
-
-#[inline]
-#[doc(hidden)]
-pub unsafe fn data_drop<'a, T>(_py: Python<'a>, obj: *mut ffi::PyObject, offset: usize) {
-    let ptr = (obj as *mut u8).offset(offset as isize) as *mut T;
-    ptr::drop_in_place(ptr)
-}
-
-#[inline]
-#[doc(hidden)]
-pub fn is_ready(_py: Python, ty: &ffi::PyTypeObject) -> bool {
-    (ty.tp_flags & ffi::Py_TPFLAGS_READY) != 0
-}
-
-/// A PythonObject that is usable as a base type with the `py_class!()` macro.
-pub trait BaseObject : PythonObject {
-    /// Gets the size of the object, in bytes.
-    fn size() -> usize;
-
-    type InitType;
-
-    /// Allocates a new object (usually by calling ty->tp_alloc),
-    /// and initializes it using init_val.
-    /// `ty` must be derived from the Self type, and the resulting object
-    /// must be of type `ty`.
-    unsafe fn alloc(py: Python, ty: &PyType, init_val: Self::InitType) -> PyResult<PyObject>;
-
-    /// Calls the rust destructor for the object and frees the memory
-    /// (usually by calling ptr->ob_type->tp_free).
-    /// This function is used as tp_dealloc implementation.
-    unsafe fn dealloc(py: Python, obj: *mut ffi::PyObject);
-}
-
-impl BaseObject for PyObject {
-    #[inline]
-    fn size() -> usize {
-        mem::size_of::<ffi::PyObject>()
-    }
-
-    type InitType = ();
-
-    unsafe fn alloc(py: Python, ty: &PyType, _init_val: ()) -> PyResult<PyObject> {
-        let ptr = ffi::PyType_GenericAlloc(ty.as_type_ptr(), 0);
-        //println!("BaseObject::alloc({:?}) = {:?}", ty.as_type_ptr(), ptr);
-        err::result_from_owned_ptr(py, ptr)
-    }
-
-    unsafe fn dealloc(_py: Python, obj: *mut ffi::PyObject) {
-        //println!("BaseObject::dealloc({:?})", ptr);
-        // Unfortunately, there is no PyType_GenericFree, so
-        // we have to manually un-do the work of PyType_GenericAlloc:
-        let ty = ffi::Py_TYPE(obj);
-        if ffi::PyType_IS_GC(ty) != 0 {
-            ffi::PyObject_GC_Del(obj as *mut c_void);
-        } else {
-            ffi::PyObject_Free(obj as *mut c_void);
-        }
-        // For heap types, PyType_GenericAlloc calls INCREF on the type objects,
-        // so we need to call DECREF here:
-        if ffi::PyType_HasFeature(ty, ffi::Py_TPFLAGS_HEAPTYPE) != 0 {
-            ffi::Py_DECREF(ty as *mut ffi::PyObject);
-        }
-    }
-}
-
--- a/src/py_class/py_class.rs
+++ b/src/py_class/py_class.rs
@ -1,480 +0,0 @@
-// Copyright (c) 2016 Daniel Grunwald
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-/**
-Defines new python extension class.
-A `py_class!` macro invocation generates code that declares a new Python class.
-Additionally, it generates a Rust struct of the same name, which allows accessing
-instances of that Python class from Rust.
-
-# Syntax
-`py_class!(pub class MyType |py| { ... })`
-
-* `pub` makes the generated Rust struct visible outside the current module. It has no effect on the visibility from Python.
-* `MyType` is the name of the Python class.
-* `py` is an identifier that will be made available as a variable of type `Python`
-in all function bodies.
-* `{ ... }` is the class body, described in more detail below.
-
-# Example
-```
-#[macro_use] extern crate pyo3;
-use pyo3::{Python, PyResult, PyDict};
-
-py_class!(class MyType |py| {
-    data number: i32;
-    def __new__(_cls, arg: i32) -> PyResult<MyType> {
-        MyType::create_instance(py, arg)
-    }
-    def half(&self) -> PyResult<i32> {
-        println!("half() was called with self={:?}", self.number(py));
-        Ok(self.number(py) / 2)
-    }
-});
-
-fn main() {
-    let gil = Python::acquire_gil();
-    let py = gil.python();
-    let dict = PyDict::new(py);
-    dict.set_item(py, "MyType", py.get_type::<MyType>()).unwrap();
-    py.run("assert MyType(42).half() == 21", None, Some(&dict)).unwrap();
-}
-```
-
-# Generated Rust type
-
-The above example generates the following Rust type:
-
-```ignore
-struct MyType { ... }
-
-impl ToPythonObject for MyType { ... }
-impl PythonObject for MyType { ... }
-impl PythonObjectWithCheckedDowncast for MyType { ... }
-impl PythonObjectWithTypeObject for MyType { ... }
-impl PythonObjectFromPyClassMacro for MyType { ... }
-
-impl MyType {
-    fn create_instance(py: Python, number: i32) -> PyResult<MyType> { ... }
-
-    // data accessors
-    fn number<'a>(&'a self, py: Python<'a>) -> &'a i32 { ... }
-
-    // functions callable from python
-    pub fn __new__(_cls: &PyType, py: Python, arg: i32) -> PyResult<MyType> {
-        MyType::create_instance(py, arg)
-    }
-
-    pub fn half(&self, py: Python) -> PyResult<i32> {
-        println!("half() was called with self={:?}", self.number(py));
-        Ok(self.number(py) / 2)
-    }
-}
-```
-
-* The generated type implements a number of traits from the `pyo3` crate.
-* The inherent `create_instance` method can create new Python objects
-  given the values for the data fields.
-* Private accessors functions are created for the data fields.
-* All functions callable from Python are also exposed as public Rust functions.
-* To convert from `MyType` to `PyObject`, use `as_object()` or `into_object()` (from the `PythonObject` trait).
-* To convert `PyObject` to `MyType`, use `obj.cast_as::<MyType>(py)` or `obj.cast_into::<MyType>(py)`.
-
-# py_class body
-The body of a `py_class!` supports the following definitions:
-
-## Data declarations
-`data data_name: data_type;`
-
-Declares a data field within the Python class.
-Used to store Rust data directly in the Python object instance.
-
-Because Python code can pass all Python objects to other threads,
-`data_type` must be `Send + 'static`.
-
-Because Python object instances can be freely shared (Python has no concept of "ownership"),
-data fields cannot be declared as `mut`.
-If mutability is required, you have to use interior mutability (`Cell` or `RefCell`).
-
-If data members are used to store references to other Python objects, make sure
-to read the section "Garbage Collector Integration".
-
-Data declarations are not accessible from Python.
-On the Rust side, data is accessed through the automatically generated accessor functions:
-```ignore
-impl MyType {
-    fn data_name<'a>(&'a self, py: Python<'a>) -> &'a data_type { ... }
-}
-```
-
-## Instance methods
-`def method_name(&self, parameter-list) -> PyResult<...> { ... }`
-
-Declares an instance method callable from Python.
-
-* Because Python objects are potentially shared, the self parameter must always
-  be a shared reference (`&self`).
-* For details on `parameter-list`, see the documentation of `py_argparse!()`.
-* The return type must be `PyResult<T>` for some `T` that implements `ToPyObject`.
-
-## Class methods
-`@classmethod def method_name(cls, parameter-list) -> PyResult<...> { ... }`
-
-Declares a class method callable from Python.
-
-* The first parameter is the type object of the class on which the method is called.
-  This may be the type object of a derived class.
-* The first parameter implicitly has type `&PyType`. This type must not be explicitly specified.
-* For details on `parameter-list`, see the documentation of `py_argparse!()`.
-* The return type must be `PyResult<T>` for some `T` that implements `ToPyObject`.
-
-## Static methods
-`@staticmethod def method_name(parameter-list) -> PyResult<...> { ... }`
-
-Declares a static method callable from Python.
-
-* For details on `parameter-list`, see the documentation of `py_argparse!()`.
-* The return type must be `PyResult<T>` for some `T` that implements `ToPyObject`.
-
-## __new__
-`def __new__(cls, parameter-list) -> PyResult<...> { ... }`
-
-Declares a constructor method callable from Python.
-
-* If no `__new__` method is declared, object instances can only be created from Rust (via `MyType::create_instance`),
-  but not from Python.
-* The first parameter is the type object of the class to create.
-  This may be the type object of a derived class declared in Python.
-* The first parameter implicitly has type `&PyType`. This type must not be explicitly specified.
-* For details on `parameter-list`, see the documentation of `py_argparse!()`.
-* The return type must be `PyResult<T>` for some `T` that implements `ToPyObject`.
-  Usually, `T` will be `MyType`.
-
-## Garbage Collector Integration
-
-If your type owns references to other python objects, you will need to
-integrate with Python's garbage collector so that the GC is aware of
-those references.
-To do this, implement the special member functions `__traverse__` and `__clear__`.
-These correspond to the slots `tp_traverse` and `tp_clear` in the Python C API.
-
-`__traverse__` must call `visit.call()` for each reference to another python object.
-
-`__clear__` must clear out any mutable references to other python objects
-(thus breaking reference cycles). Immutable references do not have to be cleared,
-as every cycle must contain at least one mutable reference.
-
-Example:
-
-```
-#[macro_use] extern crate pyo3;
-use std::{mem, cell};
-use pyo3::{PyObject, PyDrop};
-
-py_class!(class ClassWithGCSupport |py| {
-    data obj: cell::RefCell<Option<PyObject>>;
-
-    def __traverse__(&self, visit) {
-        if let Some(ref obj) = *self.obj(py).borrow() {
-            try!(visit.call(obj))
-        }
-        Ok(())
-    }
-
-    def __clear__(&self) {
-        let old_obj = mem::replace(&mut *self.obj(py).borrow_mut(), None);
-        // Release reference only after the mutable borrow has expired,
-        // see Caution note below.
-        old_obj.release_ref(py);
-    }
-});
-# fn main() {}
-```
-
-Caution: `__traverse__` may be called by the garbage collector:
-
-  * during any python operation that takes a `Python` token as argument
-  * indirectly from the `PyObject` (or derived type) `Drop` implementation
-  * if your code releases the GIL, at any time by other threads.
-
-If you are using `RefCell<PyObject>`, you must not perform any of the above
-operations while your code holds a mutable borrow, or you may cause the borrow
-in `__traverse__` to panic.
-
-This is why the example above uses the `mem::replace`/`release_ref` dance:
-`release_ref` (or the implicit `Drop`) can only be called safely in a separate
-statement, after the mutable borrow on the `RefCell` has expired.
-
-Note that this restriction applies not only to `__clear__`, but to all methods
-that use `RefCell::borrow_mut`.
-
-## Iterator Types
-
-Iterators can be defined using the Python special methods `__iter__` and `__next__`:
-
-  * `def __iter__(&self) -> PyResult<impl ToPyObject>`
-  * `def __next__(&self) -> PyResult<Option<impl ToPyObject>>`
-
-    Returning `Ok(None)` from `__next__` indicates that that there are no further items.
-
-Example:
-
-```
-#[macro_use] extern crate pyo3;
-use std::cell::RefCell;
-use pyo3::{PyObject, PyClone, PyResult};
-
-py_class!(class MyIterator |py| {
-    data iter: RefCell<Box<Iterator<Item=PyObject> + Send>>;
-
-    def __iter__(&self) -> PyResult<Self> {
-        Ok(self.clone_ref(py))
-    }
-
-    def __next__(&self) -> PyResult<Option<PyObject>> {
-        Ok(self.iter(py).borrow_mut().next())
-    }
-});
-# fn main() {}
-```
-
-## String Conversions
-
-  * `def __repr__(&self) -> PyResult<impl ToPyObject<ObjectType=PyString>>`
-  * `def __str__(&self) -> PyResult<impl ToPyObject<ObjectType=PyString>>`
-
-    Possible return types for `__str__` and `__repr__` are `PyResult<String>` or `PyResult<PyString>`.
-
-    In Python 2.7, Unicode strings returned by `__str__` and `__repr__` will be converted to byte strings
-    by the Python runtime, which results in an exception if the string contains non-ASCII characters.
-
-  * `def __bytes__(&self) -> PyResult<PyBytes>`
-
-    On Python 3.x, provides the conversion to `bytes`.
-    On Python 2.7, `__bytes__` is allowed but has no effect.
-
-  * `def __unicode__(&self) -> PyResult<PyUnicode>`
-
-    On Python 2.7, provides the conversion to `unicode`.
-    On Python 3.x, `__unicode__` is allowed but has no effect.
-
-  * `def __format__(&self, format_spec: &str) -> PyResult<impl ToPyObject<ObjectType=PyString>>`
-
-    Special method that is used by the `format()` builtin and the `str.format()` method.
-    Possible return types are `PyResult<String>` or `PyResult<PyString>`.
-
-## Comparison operators
-
-  * `def __richcmp__(&self, other: impl FromPyObject, op: CompareOp) -> PyResult<impl ToPyObject>`
-
-    Overloads Python comparison operations (`==`, `!=`, `<`, `<=`, `>`, and `>=`).
-    The `op` argument indicates the comparison operation being performed.
-    The return type will normally be `PyResult<bool>`, but any Python object can be returned.
-
-    If `other` is not of the type specified in the signature, the generated code will
-    automatically `return NotImplemented`.
-
-  * `def __hash__(&self) -> PyResult<impl PrimInt>`
-
-    Objects that compare equal must have the same hash value.
-    The return type must be `PyResult<T>` where `T` is one of Rust's primitive integer types.
-
-## Emulating Container Types
-
-  * `def __len__(&self) -> PyResult<usize>`
-
-    Called by the built-in Python function `len()`.
-
-  * `def __length_hint__(&self) -> PyResult<usize>`
-
-    Should return an estimated length for the object.
-    This method is purely an optimization and is never required for correctness.
-
-    `__length_hint__` is new in Python 3.4; older versions will ignore the method.
-
-  * `def __getitem__(&self, key: impl FromPyObject) -> PyResult<impl ToPyObject>`
-
-    Called by the Python subscript operator `self[key]`.
-
-  * `def __setitem__(&self, key: impl FromPyObject, value: impl FromPyObject) -> PyResult<()>`
-
-    Called by Python `self[key] = value`.
-
-  * `def __delitem__(&self, key: impl FromPyObject) -> PyResult<()>`
-
-    Called by Python `del self[key]`.
-
-  * `def __reversed__(&self) -> PyResult<impl ToPyObject>`
-
-    Called by the `reversed()` built-in.
-    It should return a new iterator object that iterates over all the objects in the container in reverse order.
-
-  * `def __contains__(&self, item: impl FromPyObject) -> PyResult<bool>`
-
-    Called by Python `item in self`.
-    For mapping types, this should consider the keys of the mapping rather than the values
-    or the key-item pairs.
-
-    If extraction of the `item` parameter fails with `TypeError`,
-    `__contains__` will return `Ok(false)`.
-
-## Arithmetic methods
-
-  * `def __add__(lhs, rhs) -> PyResult<impl ToPyObject>`
-  * `def __sub__(lhs, rhs) -> PyResult<impl ToPyObject>`
-  * `def __mul__(lhs, rhs) -> PyResult<impl ToPyObject>`
-  * `def __lshift__(lhs, rhs) -> PyResult<impl ToPyObject>`
-  * `def __rshift__(lhs, rhs) -> PyResult<impl ToPyObject>`
-  * `def __and__(lhs, rhs) -> PyResult<impl ToPyObject>`
-  * `def __xor__(lhs, rhs) -> PyResult<impl ToPyObject>`
-  * `def __or__(lhs, rhs) -> PyResult<impl ToPyObject>`
-
-    The parameters `lhs` and `rhs` must not be given an explicit type.
-    Within the method bodies, both parameters will implicitly have type `&PyObject`.
-
-    There are no separate "reversed" versions of these methods (`__radd__()`, etc.)
-    Instead, if the first operand cannot perform the operation,
-    the same method of the second operand is called, with the operands in the same order.
-
-    This means that you can't rely on the first parameter of these methods being `self`
-    or being the correct type, and you should test the types of both operands before deciding what to do.
-    If you can't handle the combination of types you've been given,
-    you should return `Ok(py.NotImplemented())`.
-
-  * `def __iadd__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __isub__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __imul__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __imatmul__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __itruediv__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __ifloordiv__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __imod__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __ilshift__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __irshift__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __iand__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __ixor__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-  * `def __ior__(&self, other: impl FromPyObject) -> PyResult<impl ToPyObject>`
-
-    Handles inplace operations if possible, falling back to the non-inplace versions.
-    These methods must return a new reference! In the common case of returning the
-    same (mutated) object, you will want to return `Ok(self.clone_ref(py))`.
-
-    If you can't handle the combination of types you've been given,
-    you should return `Ok(py.NotImplemented())`.
-
-## Context Manager
-
-  * `def __enter__(&self) -> PyResult<impl ToPyObject>`
-  * `def __exit__(&self, ty: Option<PyType>, value: PyObject, traceback: PyObject) -> PyResult<bool>`
-
-## Other Special Methods
-
-  * `def __bool__(&self) -> PyResult<bool>`
-
-    Determines the "truthyness" of the object.
-
-    Note that `py_class!` always expects this member to be called `__bool__`,
-    even on Python 2.7 where the Python spelling was `__nonzero__`.
-
-  * `def __call__(&self, parameter-list) -> PyResult<impl ToPyObject>`
-
-    For details on `parameter-list`, see the documentation of `py_argparse!()`.
-    The return type must be `PyResult<T>` for some `T` that implements `ToPyObject`.
-
-
-*/
-#[macro_export]
-macro_rules! py_class {
-    (class $class:ident |$py: ident| { $( $body:tt )* }) => (
-        py_class_impl! {
-            { $( $body )* }
-            $class $py
-            /* info: */ {
-                /* base_type: */ $crate::PyObject,
-                /* size: */ <$crate::PyObject as $crate::py_class::BaseObject>::size(),
-                /* class_visibility: */ {},
-                /* gc: */ {
-                    /* traverse_proc: */ None,
-                    /* traverse_data: */ [ /*name*/ ]
-                },
-                /* data: */ [ /* { offset, name, type } */ ]
-                // TODO: base type, documentation, ...
-            }
-            /* slots: */ {
-                /* type_slots */  [ /* slot: expr, */ ]
-                /* as_async */    [ /* slot: expr, */ ]
-                /* as_number */   [ /* slot: expr, */ ]
-                /* as_sequence */ [ /* slot: expr, */ ]
-                /* as_mapping */  [ /* slot: expr, */ ]
-                /* as_buffer */   [ /* slot: expr, */ ]
-                /* setitem_delitem */ [
-                    sdi_setitem: {},
-                    sdi_delitem: {},
-                ]
-            }
-            /* impls: */ { /* impl body */ }
-            /* members: */ { /* ident = expr; */ }
-            /* properties: */ { /* expr; */ }
-        }
-    );
-    (pub class $class:ident |$py: ident| { $( $body:tt )* }) => (
-        py_class_impl! {
-            { $( $body )* }
-            $class $py
-            /* info: */ {
-                /* base_type: */ $crate::PyObject,
-                /* size: */ <$crate::PyObject as $crate::py_class::BaseObject>::size(),
-                /* class_visibility: */ {pub},
-                /* gc: */ {
-                    /* traverse_proc: */ None,
-                    /* traverse_data: */ [ /*name*/ ]
-                },
-                /* data: */ [ /* { offset, name, type } */ ]
-                // TODO: base type, documentation, ...
-            }
-            /* slots: */ {
-                /* type_slots */  [ /* slot: expr, */ ]
-                /* as_async */    [ /* slot: expr, */ ]
-                /* as_number */   [ /* slot: expr, */ ]
-                /* as_sequence */ [ /* slot: expr, */ ]
-                /* as_mapping */  [ /* slot: expr, */ ]
-                /* as_buffer */   [ /* slot: expr, */ ]
-                /* setitem_delitem */ [
-                    sdi_setitem: {},
-                    sdi_delitem: {},
-                ]
-            }
-            /* impls: */ { /* impl body */ }
-            /* members: */ { /* ident = expr; */ }
-            /* properties: */ { /* expr; */ }
-        }
-    );
-}
-
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_impl_item {
-    { $class:ident, $py:ident, $name:ident( $( $selfarg:tt )* )
-        $res_type:ty; $body:block [ $( { $pname:ident : $ptype:ty = $detail:tt } )* ]
-    } => { py_coerce_item! {
-        impl $class {
-            pub fn $name($( $selfarg )* $py: $crate::Python $( , $pname: $ptype )* )
-            -> $res_type $body
-        }
-    }}
-}
--- a/src/py_class/py_class_impl.py
+++ b/src/py_class/py_class_impl.py
@ -1,827 +0,0 @@
-#!/usr/bin/env python
-
-"""
-This python script generates the py_class_impl! macro.
-"""
-
-from collections import namedtuple
-import sys, os
-
-PY2 = (os.getenv('PY') == '2')
-
-header = '''
-// Copyright (c) 2016 Daniel Grunwald
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-'''
-
-macro_start = '''
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_impl {
-    // TT muncher macro. Results are accumulated in $info $slots $impls and $members.
-'''
-
-base_case = '''
-    // Base case: we're done munching and can start producing code:
-    {   {}
-        $class:ident $py:ident
-        /* info: */ {
-            $base_type:ty,
-            $size:expr,
-            { $( $class_visibility:tt )* },
-            $gc:tt,
-            /* data: */ [ $( { $data_offset:expr, $data_name:ident, $data_ty:ty } )* ]
-        }
-        $slots:tt { $( $imp:item )* } $members:tt $properties:tt
-    } => {
-        py_coerce_item! {
-            $($class_visibility)* struct $class { _unsafe_inner: $crate::PyObject }
-        }
-
-        py_impl_to_py_object_for_python_object!($class);
-        py_impl_from_py_object_for_python_object!($class);
-
-        impl $crate::PythonObject for $class {
-            #[inline]
-            fn as_object(&self) -> &$crate::PyObject {
-                &self._unsafe_inner
-            }
-
-            #[inline]
-            fn into_object(self) -> $crate::PyObject {
-                self._unsafe_inner
-            }
-
-            /// Unchecked downcast from PyObject to Self.
-            /// Undefined behavior if the input object does not have the expected type.
-            #[inline]
-            unsafe fn unchecked_downcast_from(obj: $crate::PyObject) -> Self {
-                $class { _unsafe_inner: obj }
-            }
-
-            /// Unchecked downcast from PyObject to Self.
-            /// Undefined behavior if the input object does not have the expected type.
-            #[inline]
-            unsafe fn unchecked_downcast_borrow_from<'a>(obj: &'a $crate::PyObject) -> &'a Self {
-                ::std::mem::transmute(obj)
-            }
-        }
-
-        impl $crate::PythonObjectWithCheckedDowncast for $class {
-            #[inline]
-            fn downcast_from<'p>(py: $crate::Python<'p>, obj: $crate::PyObject) -> Result<$class, $crate::PythonObjectDowncastError<'p>> {
-                if py.get_type::<$class>().is_instance(py, &obj) {
-                    Ok($class { _unsafe_inner: obj })
-                } else {
-                    Err($crate::PythonObjectDowncastError(py))
-                }
-            }
-
-            #[inline]
-            fn downcast_borrow_from<'a, 'p>(py: $crate::Python<'p>, obj: &'a $crate::PyObject) -> Result<&'a $class, $crate::PythonObjectDowncastError<'p>> {
-                if py.get_type::<$class>().is_instance(py, obj) {
-                    unsafe { Ok(::std::mem::transmute(obj)) }
-                } else {
-                    Err($crate::PythonObjectDowncastError(py))
-                }
-            }
-        }
-
-        py_coerce_item! {
-            impl $crate::py_class::BaseObject for $class {
-                type InitType = ( $( $data_ty, )* );
-
-                #[inline]
-                fn size() -> usize {
-                    $size
-                }
-
-                unsafe fn alloc(
-                    py: $crate::Python,
-                    ty: &$crate::PyType,
-                    ( $( $data_name, )* ): Self::InitType
-                ) -> $crate::PyResult<$crate::PyObject>
-                {
-                    let obj = try!(<$base_type as $crate::py_class::BaseObject>::alloc(py, ty, ()));
-                    $( $crate::py_class::data_init::<$data_ty>(py, &obj, $data_offset, $data_name); )*
-                    Ok(obj)
-                }
-
-                unsafe fn dealloc(py: $crate::Python, obj: *mut $crate::_detail::ffi::PyObject) {
-                    $( $crate::py_class::data_drop::<$data_ty>(py, obj, $data_offset); )*
-                    <$base_type as $crate::py_class::BaseObject>::dealloc(py, obj)
-                }
-            }
-        }
-        $($imp)*
-        py_coerce_item! {
-            impl $class {
-                fn create_instance(py: $crate::Python $( , $data_name : $data_ty )* ) -> $crate::PyResult<$class> {
-                    let obj = try!(unsafe {
-                        <$class as $crate::py_class::BaseObject>::alloc(
-                            py, &py.get_type::<$class>(), ( $($data_name,)* )
-                        )
-                    });
-                    return Ok($class { _unsafe_inner: obj });
-
-                    // hide statics in create_instance to avoid name conflicts
-                    static mut TYPE_OBJECT : $crate::_detail::ffi::PyTypeObject
-                        = py_class_type_object_static_init!($class, $gc, $slots);
-                    static mut INIT_ACTIVE: bool = false;
-
-                    // trait implementations that need direct access to TYPE_OBJECT
-                    impl $crate::PythonObjectWithTypeObject for $class {
-                        fn type_object(py: $crate::Python) -> $crate::PyType {
-                            unsafe {
-                                if $crate::py_class::is_ready(py, &TYPE_OBJECT) {
-                                    $crate::PyType::from_type_ptr(py, &mut TYPE_OBJECT)
-                                } else {
-                                    // automatically initialize the class on-demand
-                                    <$class as $crate::py_class::PythonObjectFromPyClassMacro>::initialize(py, None)
-                                        .expect(concat!("An error occurred while initializing class ", stringify!($class)))
-                                }
-                            }
-                        }
-                    }
-
-                    impl $crate::py_class::PythonObjectFromPyClassMacro for $class {
-                        fn initialize(py: $crate::Python, module_name: Option<&str>) -> $crate::PyResult<$crate::PyType> {
-                            unsafe {
-                                if $crate::py_class::is_ready(py, &TYPE_OBJECT) {
-                                    return Ok($crate::PyType::from_type_ptr(py, &mut TYPE_OBJECT));
-                                }
-                                assert!(!INIT_ACTIVE,
-                                    concat!("Reentrancy detected: already initializing class ",
-                                    stringify!($class)));
-                                INIT_ACTIVE = true;
-                                let res = init(py, module_name);
-                                INIT_ACTIVE = false;
-                                res
-                            }
-                        }
-
-                        fn add_to_module(py: $crate::Python, module: &$crate::PyModule) -> $crate::PyResult<()> {
-                            let ty = <$class as $crate::py_class::PythonObjectFromPyClassMacro>::initialize(py, module.name(py).ok())?;
-                            module.add(py, stringify!($class), ty)
-                        }
-                    }
-
-                    fn init($py: $crate::Python, module_name: Option<&str>) -> $crate::PyResult<$crate::PyType> {
-                        py_class_type_object_dynamic_init!($class, $py, TYPE_OBJECT, module_name, $slots);
-                        py_class_init_members!($class, $py, TYPE_OBJECT, $members);
-                        py_class_init_properties!($class, $py, TYPE_OBJECT, $properties);
-                        unsafe {
-                            if $crate::_detail::ffi::PyType_Ready(&mut TYPE_OBJECT) == 0 {
-                                Ok($crate::PyType::from_type_ptr($py, &mut TYPE_OBJECT))
-                            } else {
-                                Err($crate::PyErr::fetch($py))
-                            }
-                        }
-                    }
-                }
-            }
-        }
-    };
-
-    { { property $name:ident { $($body:tt)* } $($tail:tt)* }
-        $class:ident $py:ident $info:tt $slots:tt { $( $imp:item )* } $members:tt
-        { $( $properties:expr; )* }
-    } => { py_class_impl! {
-        { $($tail)* }
-        $class $py $info $slots { $($imp)* } $members
-        /* properties: */ {
-            $( $properties; )*
-            py_class_property_impl! { { $($body)* } $class $py $name { } };
-        }
-    }};
-'''
-
-indentation = ['    ']
-last_char = '\n'
-
-def write(text):
-    global last_char
-    for line in text.splitlines(True):
-        line = line.lstrip(' ')
-        if len(line.strip()) == 0 and last_char == '\n':
-            continue
-        if last_char == '\n':
-            initial_closing = 0
-            for c in line:
-                if c in ']}':
-                    initial_closing += 1
-                else:
-                    break
-            if initial_closing:
-                sys.stdout.write(''.join(indentation[:-initial_closing]))
-            else:
-                sys.stdout.write(''.join(indentation))
-        elif last_char not in ' \n' and len(line) > 0 and line[0] not in ' \n;':
-            sys.stdout.write(' ')
-        sys.stdout.write(line)
-        min_indent_level = len(indentation)
-        for c in line:
-            if c in '[{':
-                if len(indentation) > min_indent_level:
-                    indentation.append('')
-                else:
-                    indentation.append('    ')
-            elif c in ']}':
-                indentation.pop()
-                if len(indentation) < min_indent_level:
-                    min_indent_level = len(indentation)
-        last_char = line[-1]
-
-slot_groups = (
-    ('tp', 'type_slots', None),
-    ('am', 'as_async', None),
-    ('nb', 'as_number', None),
-    ('sq', 'as_sequence', None),
-    ('mp', 'as_mapping', None),
-    ('bf', 'as_buffer', None),
-    ('sdi', 'setdelitem', ['sdi_setitem', 'sdi_delitem'])
-)
-
-def generate_case(pattern, old_info=None, new_info=None, new_impl=None, new_slots=None, new_members=None):
-    write('{ { %s $($tail:tt)* }\n' % pattern)
-    write('$class:ident $py:ident')
-    if old_info is not None:
-        write(old_info)
-    elif new_info is not None:
-        write('\n/* info: */ {\n')
-        write('$base_type: ty,\n')
-        write('$size: expr,\n')
-        write('$class_visibility: tt,\n')
-        write('$gc: tt,\n')
-        write('[ $( $data:tt )* ]\n')
-        write('}\n')
-    else:
-        write('$info:tt')
-    if new_slots:
-        write('\n/* slots: */ {\n')
-        for prefix, group_name, explicit_slots in slot_groups:
-            if any(s.startswith(prefix) for s, v in new_slots):
-                if explicit_slots is None:
-                    write('\n/* %s */ [ $( $%s_slot_name:ident : $%s_slot_value:expr, )* ]\n'
-                          % (group_name, prefix, prefix))
-                else:
-                    write('\n/* %s */ [\n' % group_name)
-                    for slot in explicit_slots:
-                        if any(s == slot for s, v in new_slots):
-                            write('%s: {},\n' % slot)
-                        else:
-                            write('%s: $%s_slot_value:tt,\n' % (slot, slot))
-                    write(']\n')
-            else:
-                write('$%s:tt' % group_name)
-        write('\n}\n')
-    else:
-        write('$slots:tt')
-    if new_impl is not None:
-        write('\n{ $( $imp:item )* }\n')
-    else:
-        write('$impls:tt')
-    if new_members:
-        write('\n{ $( $member_name:ident = $member_expr:expr; )* }')
-    else:
-        write('$members:tt')
-
-    write('$properties:tt')
-
-    write('\n} => { py_class_impl! {\n')
-    write('{ $($tail)* }\n')
-    write('$class $py')
-    write(new_info or '$info')
-    if new_slots:
-        write('\n/* slots: */ {\n')
-        for prefix, group_name, explicit_slots in slot_groups:
-            if any(s.startswith(prefix) for s, v in new_slots):
-                write('\n/* %s */ [\n' % group_name)
-                if explicit_slots is None:
-                    write('$( $%s_slot_name : $%s_slot_value, )*\n' % (prefix, prefix))
-                    for s, v in new_slots:
-                        if s.startswith(prefix):
-                            write('%s: %s,\n' % (s, v))
-                else:
-                    for slot in explicit_slots:
-                        slot_value = next((v for s, v in new_slots if s == slot), None)
-                        if slot_value is None:
-                            write('%s: $%s_slot_value,\n' % (slot, slot))
-                        else:
-                            write('%s: { %s },\n' % (slot, slot_value))
-                write(']\n')
-            else:
-                write('$%s' % group_name)
-        write('\n}\n')
-    else:
-        write('$slots')
-    if new_impl is not None:
-        write('\n/* impl: */ {\n')
-        write('$($imp)*\n')
-        write(new_impl)
-        write('\n}\n')
-    else:
-        write('$impls')
-    if new_members:
-        write('\n/* members: */ {\n')
-        write('$( $member_name = $member_expr; )*\n')
-        for name, val in new_members:
-            write('%s = %s;\n' % (name, val))
-        write('}')
-    else:
-        write('$members')
-    write('$properties')
-    write('\n}};\n')
-
-def data_decl():
-    generate_case('data $data_name:ident : $data_type:ty;',
-        new_info = '''
-        /* info: */ {
-            $base_type,
-            /* size: */ $crate::py_class::data_new_size::<$data_type>($size),
-            $class_visibility,
-            $gc,
-            /* data: */ [
-                $($data)*
-                {
-                    $crate::py_class::data_offset::<$data_type>($size),
-                    $data_name,
-                    $data_type
-                }
-            ]
-        }
-        ''',
-        new_impl='''
-            impl $class {
-                fn $data_name<'a>(&'a self, py: $crate::Python<'a>) -> &'a $data_type {
-                    unsafe {
-                        $crate::py_class::data_get::<$data_type>(
-                            py,
-                            &self._unsafe_inner,
-                            $crate::py_class::data_offset::<$data_type>($size)
-                        )
-                    }
-                }
-            }
-        ''')
-
-def generate_class_method(special_name=None, decoration='',
-        slot=None, add_member=False, value_macro=None, value_args=None):
-    name_pattern = special_name or '$name:ident'
-    name_use = special_name or '$name'
-    def impl(with_params):
-        if with_params:
-            param_pattern = ', $($p:tt)+'
-            impl = '''py_argparse_parse_plist_impl!{
-                py_class_impl_item { $class, $py, %s($cls: &$crate::PyType,) $res_type; { $($body)* } }
-                [] ($($p)+,)
-            }''' % name_use
-            value = 'py_argparse_parse_plist_impl!{%s {%s} [] ($($p)+,)}' \
-                    % (value_macro, value_args)
-        else:
-            param_pattern = ''
-            impl = 'py_class_impl_item! { $class, $py,%s($cls: &$crate::PyType,) $res_type; { $($body)* } [] }' \
-                % name_use
-            value = '%s!{%s []}' % (value_macro, value_args)
-        pattern = '%s def %s ($cls:ident%s) -> $res_type:ty { $( $body:tt )* }' \
-            % (decoration, name_pattern, param_pattern)
-        slots = []
-        if slot is not None:
-            slots.append((slot, value))
-        members = []
-        if add_member:
-            members.append((name_use, value))
-        generate_case(pattern, new_impl=impl, new_slots=slots, new_members=members)
-    impl(False) # without parameters
-    impl(True) # with parameters
-
-def traverse_and_clear():
-    generate_case('def __traverse__(&$slf:tt, $visit:ident) $body:block',
-        old_info = '''
-        /* info: */ {
-            $base_type: ty,
-            $size: expr,
-            $class_visibility: tt,
-            /* gc: */ {
-                /* traverse_proc: */ None,
-                $traverse_data: tt
-            },
-            $datas: tt
-        }
-        ''',
-        new_info='''
-        /* info: */ {
-            $base_type,
-            $size,
-            $class_visibility,
-            /* gc: */ {
-                /* traverse_proc: */ $class::__traverse__,
-                $traverse_data
-            },
-            $datas
-        }
-        ''',
-        new_impl='''
-            py_coerce_item!{
-                impl $class {
-                    fn __traverse__(&$slf,
-                        $py: $crate::Python,
-                        $visit: $crate::py_class::gc::VisitProc)
-                    -> Result<(), $crate::py_class::gc::TraverseError>
-                    $body
-                }
-            }
-        ''')
-    generate_case('def __clear__ (&$slf:ident) $body:block',
-        new_slots=[('tp_clear', 'py_class_tp_clear!($class)')],
-        new_impl='''
-            py_coerce_item!{
-                impl $class {
-                    fn __clear__(&$slf, $py: $crate::Python) $body
-                }
-            }
-        ''')
-
-def generate_instance_method(special_name=None, decoration='',
-        slot=None, add_member=False, value_macro=None, value_args=None):
-    name_pattern = special_name or '$name:ident'
-    name_use = special_name or '$name'
-    def impl(with_params):
-        if with_params:
-            param_pattern = ', $($p:tt)+'
-            impl = '''py_argparse_parse_plist_impl!{
-                py_class_impl_item { $class, $py, %s(&$slf,) $res_type; { $($body)* } }
-                [] ($($p)+,)
-            }''' % name_use
-            value = 'py_argparse_parse_plist_impl!{%s {%s} [] ($($p)+,)}' \
-                    % (value_macro, value_args)
-        else:
-            param_pattern = ''
-            impl = 'py_class_impl_item! { $class, $py, %s(&$slf,) $res_type; { $($body)* } [] }' \
-                % name_use
-            value = '%s!{%s []}' % (value_macro, value_args)
-        pattern = '%s def %s (&$slf:ident%s) -> $res_type:ty { $( $body:tt )* }' \
-            % (decoration, name_pattern, param_pattern)
-        slots = []
-        if slot is not None:
-            slots.append((slot, value))
-        members = []
-        if add_member:
-            members.append((name_use, value))
-        generate_case(pattern, new_impl=impl, new_slots=slots, new_members=members)
-    impl(False) # without parameters
-    impl(True) # with parameters
-
-def static_method():
-    generate_case(
-        '@staticmethod def $name:ident ($($p:tt)*) -> $res_type:ty { $( $body:tt )* }',
-        new_impl='''
-            py_argparse_parse_plist!{
-                py_class_impl_item { $class, $py, $name() $res_type; { $($body)* } }
-                ($($p)*)
-            }
-        ''',
-        new_members=[('$name', '''
-            py_argparse_parse_plist!{
-                py_class_static_method {$py, $class::$name}
-                ($($p)*)
-            }
-        ''')])
-
-def static_data():
-    generate_case('static $name:ident = $init:expr;',
-        new_members=[('$name', '$init')])
-
-macro_end = '''
-}
-'''
-
-def special_method(decorated_function):
-    def wrap1(*args, **kwargs):
-        def wrap2(special_name):
-            return decorated_function(special_name, *args, **kwargs)
-        return wrap2
-    return wrap1
-
-@special_method
-def error(special_name, msg):
-    print('''
-    { { def %s $($tail:tt)* } $( $stuff:tt )* } => {
-        py_error! { "%s" }
-    };''' % (special_name, msg))
-
-@special_method
-def unimplemented(special_name):
-    return error('%s is not supported by py_class! yet.' % special_name)(special_name)
-
-@special_method
-def normal_method(special_name):
-    pass
-
-@special_method
-def special_class_method(special_name, *args, **kwargs):
-    generate_class_method(special_name=special_name, *args, **kwargs)
-
-
-class Argument(object):
-    def __init__(self, name, arg_type=None):
-        self.name = name
-
-        if arg_type is not None:
-            if arg_type == 'int':
-                arg_type = '$crate::_detail::libc::c_int'
-
-        self.type = arg_type
-
-    def get_type(self):
-        if self.type is not None:
-            return self.type
-        else:
-            return '$%s_type' % self.name
-
-    def get_arg_pattern(self):
-        if self.type is not None:
-            return ', ${0}:ident '.format(self.name)
-        else:
-            return ', ${0}:ident : ${0}_type:ty'.format(self.name)
-
-    def get_arg_param_item(self):
-        return '{{ ${0} : {1} = {{}} }}'.format(self.name, self.get_type())
-
-
-@special_method
-def operator(special_name, slot,
-             args=(),
-             wrapper=None,
-             res_type='PyObject',
-             res_conv=None,
-             res_ffi_type='*mut $crate::_detail::ffi::PyObject',
-             additional_slots=()
-):
-    if res_conv is None:
-        if res_type == 'void':
-            res_conv = '$crate::py_class::slots::VoidCallbackConverter'
-        if res_type == '()':
-            res_conv = '$crate::py_class::slots::UnitCallbackConverter'
-            res_ffi_type = '$crate::_detail::libc::c_int'
-        elif res_type == 'bool':
-            res_conv = '$crate::py_class::slots::BoolConverter'
-            res_ffi_type = '$crate::_detail::libc::c_int'
-        elif res_type == 'PyObject':
-            res_conv = '$crate::_detail::PyObjectCallbackConverter'
-        else:
-            res_conv = '$crate::_detail::PythonObjectCallbackConverter::<$crate::%s>(::std::marker::PhantomData)' % res_type
-    arg_pattern = ''
-    param_list = []
-    for arg in args:
-        arg_pattern += arg.get_arg_pattern()
-        param_list.append(arg.get_arg_param_item())
-    if slot == 'sq_contains':
-        new_slots = [(slot, 'py_class_contains_slot!($class::%s, $%s_type)' % (special_name, args[0].name))]
-    elif slot == 'tp_richcompare':
-        new_slots = [(slot, 'py_class_richcompare_slot!($class::%s, $%s_type, %s, %s)'
-                            % (special_name, args[0].name, res_ffi_type, res_conv))]
-    elif len(args) == 0:
-        new_slots = [(slot, 'py_class_unary_slot!($class::%s, %s, %s)'
-                             % (special_name, res_ffi_type, res_conv))]
-    elif len(args) == 1:
-        new_slots = [(slot, 'py_class_binary_slot!($class::%s, %s, %s, %s)'
-                             % (special_name, args[0].get_type(), res_ffi_type, res_conv))]
-    elif len(args) == 2:
-        if wrapper is None:
-            wrapper = 'py_class_ternary_slot'
-        new_slots = [(slot, '%s!($class::%s, %s, %s, %s, %s)'
-                             % (wrapper, special_name, args[0].get_type(), args[1].get_type(), res_ffi_type, res_conv))]
-    else:
-        raise ValueError('Unsupported argument count')
-    generate_case(
-        pattern='def %s(&$slf:ident%s) -> $res_type:ty { $($body:tt)* }' % (special_name, arg_pattern),
-        new_impl='py_class_impl_item! { $class, $py, %s(&$slf,) $res_type; { $($body)* } [%s] }'
-                 % (special_name, ' '.join(param_list)),
-        new_slots=new_slots + list(additional_slots)
-    )
-    # Generate fall-back matcher that produces an error
-    # when using the wrong method signature
-    error('Invalid signature for operator %s' % special_name)(special_name)
-
-@special_method
-def call_operator(special_name, slot):
-    generate_instance_method(
-        special_name=special_name,
-        slot=slot,
-        value_macro='py_class_call_slot',
-        value_args='$class::%s' % special_name)
-
-@special_method
-def binary_numeric_operator(special_name, slot):
-    generate_case(
-        pattern='def %s($left:ident, $right:ident) -> $res_type:ty { $($body:tt)* }'
-            % special_name,
-        new_impl='py_class_impl_item! { $class, $py, %s() $res_type; { $($body)* } ' % special_name
-                +'[ { $left : &$crate::PyObject = {} } { $right : &$crate::PyObject = {} } ] }',
-        new_slots=[(slot, 'py_class_binary_numeric_slot!($class::%s)' % special_name)]
-    )
-    error('Invalid signature for binary numeric operator %s' % special_name)(special_name)
-
-@special_method
-def reflected_numeric_operator(special_name):
-    error('Reflected numeric operator %s is not supported by py_class! Use __%s__ instead!'
-            % (special_name, special_name[3:-2]))(special_name)
-
-@special_method
-def inplace_numeric_operator(special_name, slot):
-    operator(slot=slot,
-             args=[Argument('other')])(special_name)
-
-special_names = {
-    '__init__': error('__init__ is not supported by py_class!; use __new__ instead.'),
-    '__new__': special_class_method(
-        slot='tp_new',
-        value_macro='py_class_wrap_newfunc',
-        value_args='$class::__new__'),
-    '__del__': error('__del__ is not supported by py_class!; Use a data member with a Drop impl instead.'),
-    '__repr__': operator('tp_repr', res_type="PyString"),
-    '__str__': operator('tp_str', res_type="PyString"),
-    '__unicode__': normal_method(),
-    '__bytes__': normal_method(),
-    '__format__': normal_method(),
-    # Comparison Operators
-    '__lt__': error('__lt__ is not supported by py_class! use __richcmp__ instead.'),
-    '__le__': error('__le__ is not supported by py_class! use __richcmp__ instead.'),
-    '__gt__': error('__gt__ is not supported by py_class! use __richcmp__ instead.'),
-    '__ge__': error('__ge__ is not supported by py_class! use __richcmp__ instead.'),
-    '__eq__': error('__eq__ is not supported by py_class! use __richcmp__ instead.'),
-    '__ne__': error('__ne__ is not supported by py_class! use __richcmp__ instead.'),
-    '__cmp__': error('__cmp__ is not supported by py_class! use __richcmp__ instead.'),
-    '__richcmp__': operator('tp_richcompare',
-        res_type='PyObject',
-        args=[Argument('other'), Argument('op')]),
-    '__hash__': operator('tp_hash',
-        res_conv='$crate::py_class::slots::HashConverter',
-        res_ffi_type='$crate::Py_hash_t'),
-    '__nonzero__': error('__nonzero__ is not supported by py_class!; use the Python 3 spelling __bool__ instead.'),
-    '__bool__': operator('nb_nonzero' if PY2 else 'nb_bool',
-        res_type='bool'),
-    # Customizing attribute access
-    '__getattr__': unimplemented(),
-    '__getattribute__': unimplemented(),
-    '__setattr__': unimplemented(),
-    '__delattr__': unimplemented(),
-    '__dir__': unimplemented(),
-
-    # Implementing Descriptors
-    '__get__': unimplemented(),
-    '__set__': unimplemented(),
-    '__delete__': unimplemented(),
-
-    # Customizing instance and subclass checks
-    '__instancecheck__': unimplemented(),
-    '__subclasscheck__': unimplemented(),
-
-    # Emulating callable objects
-    '__call__': call_operator('tp_call'),
-
-    # Emulating container types
-    '__len__': operator('sq_length',
-                res_ffi_type='$crate::_detail::ffi::Py_ssize_t',
-                res_conv='$crate::py_class::slots::LenResultConverter',
-                additional_slots=[
-                    # Use PySequence_Size to forward mp_length calls to sq_length.
-                    ('mp_length', 'Some($crate::_detail::ffi::PySequence_Size)')
-                ]),
-    '__length_hint__': normal_method(),
-    '__getitem__': operator('mp_subscript',
-                args=[Argument('key')],
-                additional_slots=[
-                    ('sq_item', 'Some($crate::py_class::slots::sq_item)')
-                ]),
-    '__missing__': normal_method(),
-    '__setitem__': operator('sdi_setitem',
-                args=[Argument('key'), Argument('value')],
-                res_type='()'),
-    '__delitem__': operator('sdi_delitem',
-                args=[Argument('key')],
-                res_type='()'),
-    '__iter__': operator('tp_iter'),
-    '__next__': operator('tp_iternext',
-                res_conv='$crate::py_class::slots::IterNextResultConverter'),
-    '__reversed__': normal_method(),
-    '__contains__': operator('sq_contains', args=[Argument('item')]),
-
-    # Emulating numeric types
-    '__add__': binary_numeric_operator('nb_add'),
-    '__sub__': binary_numeric_operator('nb_subtract'),
-    '__mul__': binary_numeric_operator('nb_multiply'),
-    '__matmul__': unimplemented(),
-    '__div__': unimplemented(),
-    '__truediv__': unimplemented(),
-    '__floordiv__': unimplemented(),
-    '__mod__': unimplemented(),
-    '__divmod__': unimplemented(),
-    '__pow__': unimplemented(),
-    '__lshift__': binary_numeric_operator('nb_lshift'),
-    '__rshift__': binary_numeric_operator('nb_rshift'),
-    '__and__': binary_numeric_operator('nb_and'),
-    '__xor__': binary_numeric_operator('nb_xor'),
-    '__or__': binary_numeric_operator('nb_or'),
-
-    # Emulating numeric types - reflected
-    '__radd__': reflected_numeric_operator(),
-    '__rsub__': reflected_numeric_operator(),
-    '__rmul__': reflected_numeric_operator(),
-    '__rmatmul__': reflected_numeric_operator(),
-    '__rdiv__': reflected_numeric_operator(),
-    '__rtruediv__': reflected_numeric_operator(),
-    '__rfloordiv__': reflected_numeric_operator(),
-    '__rmod__': reflected_numeric_operator(),
-    '__rdivmod__': reflected_numeric_operator(),
-    '__rpow__': reflected_numeric_operator(),
-    '__rlshift__': reflected_numeric_operator(),
-    '__rrshift__': reflected_numeric_operator(),
-    '__rand__': reflected_numeric_operator(),
-    '__rxor__': reflected_numeric_operator(),
-    '__ror__': reflected_numeric_operator(),
-
-    # Emulating numeric types - in-place
-    '__iadd__': inplace_numeric_operator('nb_inplace_add'),
-    '__isub__': inplace_numeric_operator('nb_inplace_subtract'),
-    '__imul__': inplace_numeric_operator('nb_inplace_multiply'),
-    '__imatmul__': inplace_numeric_operator('nb_inplace_matrix_multiply'),
-    '__idiv__': unimplemented(),
-    '__itruediv__': inplace_numeric_operator('nb_inplace_true_divide'),
-    '__ifloordiv__': inplace_numeric_operator('nb_inplace_floor_divide'),
-    '__imod__': inplace_numeric_operator('nb_inplace_remainder'),
-    '__ipow__': unimplemented(),
-    '__ilshift__': inplace_numeric_operator('nb_inplace_lshift'),
-    '__irshift__': inplace_numeric_operator('nb_inplace_rshift'),
-    '__iand__': inplace_numeric_operator('nb_inplace_and'),
-    '__ixor__': inplace_numeric_operator('nb_inplace_xor'),
-    '__ior__': inplace_numeric_operator('nb_inplace_or'),
-
-    # Unary arithmetic
-    '__neg__': operator('nb_negative'),
-    '__pos__': operator('nb_positive'),
-    '__abs__': operator('nb_absolute'),
-    '__invert__': operator('nb_invert'),
-    '__complex__': unimplemented(),
-    '__int__': unimplemented(),
-    '__long__': unimplemented(),
-    '__float__': unimplemented(),
-    '__round__': unimplemented(),
-    '__index__': unimplemented(),
-    '__coerce__': unimplemented(),
-
-    # With statement context managers
-    '__enter__': normal_method(),
-    '__exit__': normal_method(),
-}
-
-def main():
-    if sys.argv[1:] == ['--format']:
-        while True:
-            line = sys.stdin.readline()
-            if len(line) == 0:
-                return
-            write(line)
-    print(header)
-    print('')
-    print('// !!!!!!!!!!!!!!!!!!!!!!!!!!!')
-    print('// THIS IS A GENERATED FILE !!')
-    print('//       DO NOT MODIFY      !!')
-    print('// !!!!!!!!!!!!!!!!!!!!!!!!!!!')
-    print(macro_start)
-    print(base_case)
-    data_decl()
-    traverse_and_clear()
-    for name, f in sorted(special_names.items()):
-        f(name)
-    generate_instance_method(
-        add_member=True,
-        value_macro='py_class_instance_method',
-        value_args='$py, $class::$name')
-    generate_class_method(decoration='@classmethod',
-        add_member=True,
-        value_macro='py_class_class_method',
-        value_args='$py, $class::$name')
-    static_method()
-    static_data()
-    print(macro_end)
-
-if __name__ == '__main__':
-    main()
-
--- a/src/py_class/py_class_impl.rs
+++ b/src/py_class/py_class_impl.rs
--- a/src/py_class/slots.rs
+++ b/src/py_class/slots.rs
@ -1,531 +0,0 @@
-// Copyright (c) 2016 Daniel Grunwald
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-use ffi;
-use std::{isize, ptr};
-use std::os::raw::{c_int};
-use python::{Python, PythonObject};
-use conversion::ToPyObject;
-use function::CallbackConverter;
-use err::{PyErr, PyResult};
-use py_class::{CompareOp};
-use exc;
-use Py_hash_t;
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_type_object_static_init {
-    ($class_name:ident,
-     $gc:tt,
-    /* slots: */ {
-        /* type_slots */  [ $( $slot_name:ident : $slot_value:expr, )* ]
-        $as_async:tt
-        $as_number:tt
-        $as_sequence:tt
-        $as_mapping:tt
-        $as_buffer:tt
-        $setdelitem:tt
-    }) => (
-        $crate::_detail::ffi::PyTypeObject {
-            $( $slot_name : $slot_value, )*
-            ..
-                $crate::_detail::ffi::PyTypeObject_INIT
-        }
-    );
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_wrap_newfunc {
-    ($class:ident :: $f:ident [ $( { $pname:ident : $ptype:ty = $detail:tt } )* ]) => {{
-        unsafe extern "C" fn wrap_newfunc(
-            cls: *mut $crate::_detail::ffi::PyTypeObject,
-            args: *mut $crate::_detail::ffi::PyObject,
-            kwargs: *mut $crate::_detail::ffi::PyObject)
-        -> *mut $crate::_detail::ffi::PyObject
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $crate::_detail::PyObjectCallbackConverter,
-                |py| {
-                    py_argparse_raw!(py, Some(LOCATION), args, kwargs,
-                        [ $( { $pname : $ptype = $detail } )* ]
-                        {
-                            let cls = $crate::PyType::from_type_ptr(py, cls);
-                            let ret = $class::$f(&cls, py $(, $pname )* );
-                            $crate::PyDrop::release_ref(cls, py);
-                            ret
-                        })
-                })
-        }
-        Some(wrap_newfunc)
-    }}
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_as_number {
-    ([]) => (0 as *mut $crate::_detail::ffi::PyNumberMethods);
-    ([$( $slot_name:ident : $slot_value:expr ,)+]) => {{
-        static mut NUMBER_METHODS : $crate::_detail::ffi::PyNumberMethods
-            = $crate::_detail::ffi::PyNumberMethods {
-                $( $slot_name : $slot_value, )*
-                ..
-                    $crate::_detail::ffi::PyNumberMethods_INIT
-            };
-        unsafe { &mut NUMBER_METHODS }
-    }}
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_unary_slot {
-    ($class:ident :: $f:ident, $res_type:ty, $conv:expr) => {{
-        unsafe extern "C" fn wrap_unary(
-            slf: *mut $crate::_detail::ffi::PyObject)
-        -> $res_type
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $conv,
-                |py| {
-                    let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                    let ret = slf.$f(py);
-                    $crate::PyDrop::release_ref(slf, py);
-                    ret
-                })
-        }
-        Some(wrap_unary)
-    }}
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_binary_slot {
-    ($class:ident :: $f:ident, $arg_type:ty, $res_type:ty, $conv:expr) => {{
-        unsafe extern "C" fn wrap_binary(
-            slf: *mut $crate::_detail::ffi::PyObject,
-            arg: *mut $crate::_detail::ffi::PyObject)
-        -> $res_type
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $conv,
-                |py| {
-                    let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                    let arg = $crate::PyObject::from_borrowed_ptr(py, arg);
-                    let ret = match <$arg_type as $crate::FromPyObject>::extract(py, &arg) {
-                        Ok(arg) => slf.$f(py, arg),
-                        Err(e) => Err(e)
-                    };
-                    $crate::PyDrop::release_ref(arg, py);
-                    $crate::PyDrop::release_ref(slf, py);
-                    ret
-                })
-        }
-        Some(wrap_binary)
-    }}
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_ternary_slot {
-    ($class:ident :: $f:ident, $arg1_type:ty, $arg2_type:ty, $res_type:ty, $conv:expr) => {{
-        unsafe extern "C" fn wrap_binary(
-            slf: *mut $crate::_detail::ffi::PyObject,
-            arg1: *mut $crate::_detail::ffi::PyObject,
-            arg2: *mut $crate::_detail::ffi::PyObject)
-        -> $res_type
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $conv,
-                |py| {
-                    let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                    let arg1 = $crate::PyObject::from_borrowed_ptr(py, arg1);
-                    let arg2 = $crate::PyObject::from_borrowed_ptr(py, arg2);
-                    let ret = match <$arg1_type as $crate::FromPyObject>::extract(py, &arg1) {
-                        Ok(arg1) => match <$arg2_type as $crate::FromPyObject>::extract(py, &arg2) {
-                            Ok(arg2) => slf.$f(py, arg1, arg2),
-                            Err(e) => Err(e)
-                        },
-                        Err(e) => Err(e)
-                    };
-                    $crate::PyDrop::release_ref(arg1, py);
-                    $crate::PyDrop::release_ref(arg2, py);
-                    $crate::PyDrop::release_ref(slf, py);
-                    ret
-                })
-        }
-        Some(wrap_binary)
-    }}
-}
-
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_binary_internal {
-    ($class:ident :: $f:ident, $arg1_type:ty, $res_type:ty, $conv:expr) => {{
-        unsafe extern "C" fn wrap_binary(
-            slf: *mut $crate::_detail::ffi::PyObject,
-            arg1: $arg1_type)
-            -> $res_type                                                          {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $conv,
-                |py| {
-                    let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                    Ok(slf.$f(py, arg1))
-                })
-        }
-        Some(wrap_binary)
-    }}
-}
-
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_ternary_internal {
-    ($class:ident :: $f:ident, $arg1_type:ty, $arg2_type:ty, $res_type:ty, $conv:expr) => {{
-        unsafe extern "C" fn wrap(
-            slf: *mut $crate::_detail::ffi::PyObject,
-            arg1: $arg1_type,
-            arg2: $arg2_type)
-            -> $res_type
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $conv,
-                |py| {
-                    let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                    Ok(slf.$f(py, arg1, arg2))
-                })
-        }
-        Some(wrap)
-    }}
-}
-
-
-pub fn extract_op(py: Python, op: c_int) -> PyResult<CompareOp> {
-    match op {
-        ffi::Py_LT => Ok(CompareOp::Lt),
-        ffi::Py_LE => Ok(CompareOp::Le),
-        ffi::Py_EQ => Ok(CompareOp::Eq),
-        ffi::Py_NE => Ok(CompareOp::Ne),
-        ffi::Py_GT => Ok(CompareOp::Gt),
-        ffi::Py_GE => Ok(CompareOp::Ge),
-        _ => Err(PyErr::new_lazy_init(
-            py.get_type::<exc::ValueError>(),
-            Some("tp_richcompare called with invalid comparison operator".to_py_object(py).into_object())))
-    }
-}
-
-// sq_richcompare is special-cased slot
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_richcompare_slot {
-    ($class:ident :: $f:ident, $arg_type:ty, $res_type:ty, $conv:expr) => {{
-        unsafe extern "C" fn tp_richcompare(
-            slf: *mut $crate::_detail::ffi::PyObject,
-            arg: *mut $crate::_detail::ffi::PyObject,
-            op: $crate::_detail::libc::c_int)
-        -> $res_type
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $conv,
-                |py| {
-                    let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                    let arg = $crate::PyObject::from_borrowed_ptr(py, arg);
-                    let ret = match $crate::py_class::slots::extract_op(py, op) {
-                        Ok(op) => match <$arg_type as $crate::FromPyObject>::extract(py, &arg) {
-                            Ok(arg) => slf.$f(py, arg, op).map(|res| { res.into_py_object(py).into_object() }),
-                            Err(_) => Ok(py.NotImplemented())
-                        },
-                        Err(_) => Ok(py.NotImplemented())
-                    };
-                    $crate::PyDrop::release_ref(arg, py);
-                    $crate::PyDrop::release_ref(slf, py);
-                    ret
-                })
-        }
-        Some(tp_richcompare)
-    }}
-}
-
-// sq_contains is special-cased slot because it converts type errors to Ok(false)
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_contains_slot {
-    ($class:ident :: $f:ident, $arg_type:ty) => {{
-        unsafe extern "C" fn sq_contains(
-            slf: *mut $crate::_detail::ffi::PyObject,
-            arg: *mut $crate::_detail::ffi::PyObject)
-        -> $crate::_detail::libc::c_int
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $crate::py_class::slots::BoolConverter,
-                |py| {
-                    let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                    let arg = $crate::PyObject::from_borrowed_ptr(py, arg);
-                    let ret = match <$arg_type as $crate::FromPyObject>::extract(py, &arg) {
-                        Ok(arg) => slf.$f(py, arg),
-                        Err(e) => $crate::py_class::slots::type_error_to_false(py, e)
-                    };
-                    $crate::PyDrop::release_ref(arg, py);
-                    $crate::PyDrop::release_ref(slf, py);
-                    ret
-                })
-        }
-        Some(sq_contains)
-    }}
-}
-
-pub fn type_error_to_false(py: Python, e: PyErr) -> PyResult<bool> {
-    if e.matches(py, py.get_type::<exc::TypeError>()) {
-        Ok(false)
-    } else {
-        Err(e)
-    }
-}
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_binary_numeric_slot {
-    ($class:ident :: $f:ident) => {{
-        unsafe extern "C" fn binary_numeric(
-            lhs: *mut $crate::_detail::ffi::PyObject,
-            rhs: *mut $crate::_detail::ffi::PyObject)
-        -> *mut $crate::_detail::ffi::PyObject
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $crate::_detail::PyObjectCallbackConverter,
-                |py| {
-                    let lhs = $crate::PyObject::from_borrowed_ptr(py, lhs);
-                    let rhs = $crate::PyObject::from_borrowed_ptr(py, rhs);
-                    let ret = $class::$f(py, &lhs, &rhs);
-                    $crate::PyDrop::release_ref(lhs, py);
-                    $crate::PyDrop::release_ref(rhs, py);
-                    ret
-                })
-        }
-        Some(binary_numeric)
-    }}
-}
-
-
-pub struct VoidCallbackConverter;
-
-impl CallbackConverter<()> for VoidCallbackConverter {
-    type R = ();
-
-    #[inline]
-    fn convert(_: (), _: Python) -> () {
-        ()
-    }
-
-    #[inline]
-    fn error_value() -> () {
-        ()
-    }
-}
-
-
-pub struct UnitCallbackConverter;
-
-impl CallbackConverter<()> for UnitCallbackConverter {
-    type R = c_int;
-
-    #[inline]
-    fn convert(_: (), _: Python) -> c_int {
-        0
-    }
-
-    #[inline]
-    fn error_value() -> c_int {
-        -1
-    }
-}
-
-pub struct LenResultConverter;
-
-impl CallbackConverter<usize> for LenResultConverter {
-    type R = isize;
-
-    fn convert(val: usize, py: Python) -> isize {
-        if val <= (isize::MAX as usize) {
-            val as isize
-        } else {
-            PyErr::new_lazy_init(py.get_type::<exc::OverflowError>(), None).restore(py);
-            -1
-        }
-    }
-
-    #[inline]
-    fn error_value() -> isize {
-        -1
-    }
-}
-
-pub struct IterNextResultConverter;
-
-impl <T> CallbackConverter<Option<T>>
-    for IterNextResultConverter
-    where T: ToPyObject
-{
-    type R = *mut ffi::PyObject;
-
-    fn convert(val: Option<T>, py: Python) -> *mut ffi::PyObject {
-        match val {
-            Some(val) => val.into_py_object(py).into_object().steal_ptr(),
-            None => unsafe {
-                ffi::PyErr_SetNone(ffi::PyExc_StopIteration);
-                ptr::null_mut()
-            }
-        }
-    }
-
-    #[inline]
-    fn error_value() -> *mut ffi::PyObject {
-        ptr::null_mut()
-    }
-}
-
-pub trait WrappingCastTo<T> {
-    fn wrapping_cast(self) -> T;
-}
-
-macro_rules! wrapping_cast {
-    ($from:ty, $to:ty) => {
-        impl WrappingCastTo<$to> for $from {
-            #[inline]
-            fn wrapping_cast(self) -> $to {
-                self as $to
-            }
-        }
-    }
-}
-wrapping_cast!(u8, Py_hash_t);
-wrapping_cast!(u16, Py_hash_t);
-wrapping_cast!(u32, Py_hash_t);
-wrapping_cast!(usize, Py_hash_t);
-wrapping_cast!(u64, Py_hash_t);
-wrapping_cast!(i8, Py_hash_t);
-wrapping_cast!(i16, Py_hash_t);
-wrapping_cast!(i32, Py_hash_t);
-wrapping_cast!(isize, Py_hash_t);
-wrapping_cast!(i64, Py_hash_t);
-
-pub struct HashConverter;
-
-impl <T> CallbackConverter<T> for HashConverter
-    where T: WrappingCastTo<Py_hash_t>
-{
-    type R = Py_hash_t;
-
-    #[inline]
-    fn convert(val: T, _py: Python) -> Py_hash_t {
-        let hash = val.wrapping_cast();
-        if hash == -1 {
-            -2
-        } else {
-            hash
-        }
-    }
-
-    #[inline]
-    fn error_value() -> Py_hash_t {
-        -1
-    }
-}
-
-pub struct BoolConverter;
-
-impl CallbackConverter<bool> for BoolConverter {
-    type R = c_int;
-
-    #[inline]
-    fn convert(val: bool, _py: Python) -> c_int {
-        val as c_int
-    }
-
-    #[inline]
-    fn error_value() -> c_int {
-        -1
-    }
-}
-
-
-pub struct SuccessConverter;
-
-impl CallbackConverter<bool> for SuccessConverter {
-    type R = c_int;
-
-    #[inline]
-    fn convert(val: bool, _py: Python) -> c_int {
-        if val { 0 } else { -1 }
-    }
-
-    #[inline]
-    fn error_value() -> c_int {
-        -1
-    }
-}
-
-
-#[macro_export]
-#[doc(hidden)]
-macro_rules! py_class_call_slot {
-    ($class:ident :: $f:ident [ $( { $pname:ident : $ptype:ty = $detail:tt } )* ]) => {{
-        unsafe extern "C" fn wrap_call(
-            slf: *mut $crate::_detail::ffi::PyObject,
-            args: *mut $crate::_detail::ffi::PyObject,
-            kwargs: *mut $crate::_detail::ffi::PyObject)
-        -> *mut $crate::_detail::ffi::PyObject
-        {
-            const LOCATION: &'static str = concat!(stringify!($class), ".", stringify!($f), "()");
-            $crate::_detail::handle_callback(
-                LOCATION, $crate::_detail::PyObjectCallbackConverter,
-                |py| {
-                    py_argparse_raw!(py, Some(LOCATION), args, kwargs,
-                        [ $( { $pname : $ptype = $detail } )* ]
-                        {
-                            let slf = $crate::PyObject::from_borrowed_ptr(py, slf).unchecked_cast_into::<$class>();
-                            let ret = slf.$f(py $(, $pname )* );
-                            $crate::PyDrop::release_ref(slf, py);
-                            ret
-                        })
-                })
-        }
-        Some(wrap_call)
-    }}
-}
-
-/// Used as implementation in the `sq_item` slot to forward calls to the `mp_subscript` slot.
-pub unsafe extern "C" fn sq_item(obj: *mut ffi::PyObject, index: ffi::Py_ssize_t) -> *mut ffi::PyObject {
-    let arg = ffi::PyLong_FromSsize_t(index);
-    if arg.is_null() {
-        return arg;
-    }
-    let ret = ffi::PyObject_GetItem(obj, arg);
-    ffi::Py_DECREF(arg);
-    ret
-}
-