Function impl_pystruct_sequence

crates/derive-impl/src/pystructseq.rs:525–646

Attribute macro for struct sequences. Usage: ```ignore #[pystruct_sequence_data] struct StructTimeData { ... } #[pystruct_sequence(name = "struct_time", module = "time", data = "StructTimeData")] struct PyStructTime; ```

(
    attr: PunctuatedNestedMeta,
    item: Item,
)

/// struct PyStructTime;
/// ```
pub(crate) fn impl_pystruct_sequence(
    attr: PunctuatedNestedMeta,
    item: Item,
) -> Result<TokenStream> {
    let Item::Struct(struct_item) = item else {
        bail_span!(item, "#[pystruct_sequence] can only be applied to a struct");
    };

    let ident = struct_item.ident.clone();
    let fake_ident = Ident::new("pystruct_sequence", ident.span());
    let meta = PyStructSequenceMeta::from_nested(ident, fake_ident, attr.into_iter())?;

    let pytype_ident = struct_item.ident.clone();
    let pytype_vis = struct_item.vis.clone();
    let data_ident = meta.data_type()?;

    let class_name = meta.class_name()?.ok_or_else(|| {
        syn::Error::new_spanned(
            &struct_item.ident,
            "#[pystruct_sequence] requires name parameter",
        )
    })?;
    let module_name = meta.module()?;

    // Module name handling
    let module_name_tokens = match &module_name {
        Some(m) => quote!(Some(#m)),
        None => quote!(None),
    };

    let module_class_name = if let Some(ref m) = module_name {
        format!("{}.{}", m, class_name)
    } else {
        class_name.clone()
    };

    let output = quote! {
        // The Python type struct - newtype wrapping PyTuple
        #[derive(Debug)]
        #[repr(transparent)]
        #pytype_vis struct #pytype_ident(pub ::rustpython_vm::builtins::PyTuple);

        // PyClassDef for Python type
        impl ::rustpython_vm::class::PyClassDef for #pytype_ident {
            const NAME: &'static str = #class_name;
            const MODULE_NAME: Option<&'static str> = #module_name_tokens;
            const TP_NAME: &'static str = #module_class_name;
            const DOC: Option<&'static str> = None;
            const BASICSIZE: usize = 0;
            const UNHASHABLE: bool = false;

            type Base = ::rustpython_vm::builtins::PyTuple;
        }

        // StaticType for Python type
        impl ::rustpython_vm::class::StaticType for #pytype_ident {
            fn static_cell() -> &'static ::rustpython_vm::common::static_cell::StaticCell<::rustpython_vm::builtins::PyTypeRef> {
                ::rustpython_vm::common::static_cell! {