Function autogen_cpp_sum

crates/codegen/src/unrealcpp.rs:6365–6657

(
    module_prefix: &str,
    module: &ModuleDef,
    name: &str,
    sum_type: &SumTypeDef,
    api_macro: &str,
    module_name: &str,
)

}

fn autogen_cpp_sum(
    module_prefix: &str,
    module: &ModuleDef,
    name: &str,
    sum_type: &SumTypeDef,
    api_macro: &str,
    module_name: &str,
) -> String {
    use convert_case::Case;

    /* ------------------------------------------------------------------ */
    /* 1. gather #includes for every variant payload -------------------- */
    /* ------------------------------------------------------------------ */
    let mut includes = HashSet::<String>::new();
    for (_, alg_ty) in &sum_type.variants {
        collect_includes_for_type(module_prefix, module, alg_ty, &mut includes, module_name);
    }

    includes.insert("Kismet/BlueprintFunctionLibrary.h".to_string());

    let include_slices: Vec<&str> = includes.iter().map(|s| s.as_str()).collect();

    // /* ------------------------------------------------------------------ */
    // /* 2. emit boiler-plate + forward decls ----------------------------- */
    // /* ------------------------------------------------------------------ */
    let type_name = format!("{name}Type");
    let mut output = UnrealCppAutogen::new(&include_slices, &type_name, false);

    /* ------------------------------------------------------------------ */
    /* 3. generate the tag enum ----------------------------------------- */
    /* ------------------------------------------------------------------ */
    writeln!(output, "UENUM(BlueprintType)\nenum class E{name}Tag : uint8\n{{");

    let mut variant_type = HashSet::<String>::new();

    for (ix, (variant, _variant_type)) in sum_type.variants.iter().enumerate() {
        let comma = if ix + 1 == sum_type.variants.len() { "" } else { "," };
        writeln!(output, "    {}{}", variant.to_case(Case::Pascal), comma);

        let variant_cpp_type = cpp_ty_fmt_with_module(module_prefix, module, _variant_type, module_name).to_string();
        variant_type.insert(variant_cpp_type);
    }
    writeln!(output, "}};\n");

    /* ------------------------------------------------------------------ */
    /* 4. generate the UStruct ----------------------------------- */
    /* ------------------------------------------------------------------ */

    writeln!(output, "USTRUCT(BlueprintType)\nstruct {api_macro} F{name}Type\n{{");
    writeln!(output, "    GENERATED_BODY()\n");

    // default ctor
    writeln!(output, "public:\n    F{name}Type() = default;\n");

    // data + tag
    writeln!(
        output,
        "    TVariant<{}> MessageData;",