Macro type_alias 

macro_rules! type_alias {
    ($module:expr, $name:ident = $($base:ty)|+, $doc:expr) => { ... };
    ($module:expr, $name:ident = $($base:ty)|+) => { ... };
    ($module:expr, $name:ident = $ty:ty, $doc:expr) => { ... };
    ($module:expr, $name:ident = $ty:ty) => { ... };
}

Define a module-level type alias with runtime support.

This macro creates a zero-sized struct that:

• Generates a type alias entry in Python stub files (.pyi)
• Can be registered at runtime using runtime::PyModuleTypeAliasExt::add_type_alias

Syntax

// Union type
pyo3_stub_gen::type_alias!("module.name", MyUnion = TypeA | TypeB);

// Single type (alias)
pyo3_stub_gen::type_alias!("module.name", MyAlias = SomeType);

// With documentation
pyo3_stub_gen::type_alias!("module.name", MyAlias = TypeA | TypeB, "Documentation string");

Examples

use pyo3_stub_gen::type_alias;

// Define a union type alias
type_alias!("my_module", NumberOrString = i32 | String);

// Define a single type alias
type_alias!("my_module", OptionalInt = Option<i32>);

Runtime Registration

To make the type alias importable from Python, register it in your module:

use pyo3::prelude::*;
use pyo3_stub_gen::runtime::PyModuleTypeAliasExt;

type_alias!("my_module", NumberOrString = i32 | String);

#[pymodule]
fn my_module(m: &Bound<PyModule>) -> PyResult<()> {
    m.add_type_alias::<NumberOrString>()?;
    Ok(())
}