fn render_attr()

in starlark_derive/src/render.rs [71:117]

• 47 lines of code
• 1 McCabe index (conditional complexity)

fn render_attr(x: StarAttr) -> TokenStream {
    let span = x.span();
    let StarAttr {
        name,
        arg,
        attrs,
        return_type,
        return_type_arg,
        speculative_exec_safe,
        body,
        docstring,
    } = x;
    let name_str = ident_string(&name);
    let docstring = match docstring {
        Some(d) => quote_spanned!(span=> Some(#d.to_owned())),
        None => quote_spanned!(span=> None),
    };
    quote_spanned! {
        span=>
        #( #attrs )*
        #[allow(non_snake_case)] // Starlark doesn't have this convention
        fn #name<'v>(
            #[allow(unused_variables)]
            this: starlark::values::Value<'v>,
            heap: &'v starlark::values::Heap,
        ) -> anyhow::Result<starlark::values::Value<'v>> {
             fn inner<'v>(
                this: starlark::values::Value<'v>,
                #[allow(unused_variables)]
                heap: &'v starlark::values::Heap,
            ) -> #return_type {
                #[allow(unused_variables)]
                let this: #arg = match starlark::values::UnpackValue::unpack_value(this) {
                    None => return Err(starlark::values::ValueError::IncorrectParameterTypeNamedWithExpected(
                        "this".to_owned(),
                        <#arg as starlark::values::UnpackValue>::expected(),
                        this.get_type().to_owned(),
                    ).into()),
                    Some(v) => v,
                };
                #body
            }
            Ok(heap.alloc(inner(this, heap)?))
        }
        globals_builder.set_attribute_fn(#name_str, #speculative_exec_safe, #docstring, stringify!(#return_type_arg).to_owned(), #name);
    }
}