feat: added decl_name function to meta header codegen (#136)

Author: zaucy

cpp_meta_header_codegen/BUILD.bazel

@@ -9,7 +9,10 @@ cc_ecsact_codegen_plugin(
     copts = copts,
     no_validate_test = True,  # file name is too long on Windows
     output_extension = "meta.hh",
-    deps = ["//:support"],
+    deps = [
+        "//:support",
+        "//:cpp_codegen_plugin_util",
+    ],
 )
 
 alias(

cpp_meta_header_codegen/cpp_meta_header_codegen.cc

@@ -9,6 +9,7 @@
 #include "ecsact/codegen_plugin.h"
 #include "ecsact/codegen_plugin.hh"
 #include "ecsact/lang-support/lang-cc.hh"
+#include "ecsact/cpp_codegen_plugin_util.hh"
 
 namespace fs = std::filesystem;
 namespace stdr = std::ranges;
@@ -449,10 +450,31 @@ static inline auto write_lazy_system_iteration_rate( //
 		cpp_identifier(get_sys_full_name(ctx.package_id, id)),
 		"> : std::integral_constant<int32_t, ",
 		lazy_iteration_rate,
-		"> {};"
+		"> {};\n\n"
 	);
 }
 
+template<typename DeclId>
+static inline auto write_decl_full_name_specialization( //
+	ecsact::codegen_plugin_context& ctx,
+	DeclId                          id
+) {
+	using ecsact::cc_lang_support::cpp_identifier;
+	using ecsact::cpp_codegen_plugin_util::method_printer;
+
+	auto decl_id = ecsact_id_cast<ecsact_decl_id>(id);
+	auto decl_full_name = ecsact::meta::decl_full_name(decl_id);
+	auto decl_cpp_ident = cpp_identifier(decl_full_name);
+
+	auto method_name = "ecsact::decl_full_name<" + decl_cpp_ident + ">";
+
+	ctx.write("template<> constexpr ");
+	auto printer =
+		method_printer{ctx, method_name}.return_type("std::string_view");
+
+	ctx.write("return \"" + decl_full_name + "\";");
+}
+
 void ecsact_codegen_plugin(
 	ecsact_package_id         package_id,
 	ecsact_codegen_write_fn_t write_fn
@@ -615,4 +637,20 @@ void ecsact_codegen_plugin(
 	for(auto& sys_id : ecsact::meta::get_system_ids(ctx.package_id)) {
 		write_lazy_system_iteration_rate(ctx, sys_id);
 	}
+
+	for(auto& sys_id : ecsact::meta::get_system_ids(ctx.package_id)) {
+		write_decl_full_name_specialization(ctx, sys_id);
+	}
+
+	for(auto& act_id : ecsact::meta::get_action_ids(ctx.package_id)) {
+		write_decl_full_name_specialization(ctx, act_id);
+	}
+
+	for(auto& comp_id : ecsact::meta::get_component_ids(ctx.package_id)) {
+		write_decl_full_name_specialization(ctx, comp_id);
+	}
+
+	for(auto& trans_id : ecsact::meta::get_transient_ids(ctx.package_id)) {
+		write_decl_full_name_specialization(ctx, trans_id);
+	}
 }

ecsact/cpp/type_info.hh

@@ -3,10 +3,16 @@
 #include <cstdint>
 #include <type_traits>
 #include <array>
+#include <string_view>
 #include "ecsact/lib.hh"
 #include "ecsact/runtime/common.h"
 #include "ecsact/runtime/definitions.h"
 
+namespace ecsact::detail {
+template<typename>
+constexpr bool unimplemented_by_meta_cpp_codegen = false;
+}
+
 namespace ecsact {
 
 template<typename SystemLikeT>
@@ -82,4 +88,22 @@ struct field_info {
 template<typename C>
 constexpr std::array<field_info, fields_count<C>()> fields_info();
 
+/**
+ * @returns the ecsact declaration full name. The same value that should be
+ *          returned by ecsact_meta_decl_name
+ */
+template<typename Decl>
+constexpr auto decl_full_name() -> std::string_view {
+	static_assert(detail::unimplemented_by_meta_cpp_codegen<Decl>, R"(
+ -----------------------------------------------------------------------------
+| (!) CODEGEN ERROR                                                           |
+| `ecsact::decl_full_name<>` template specialization cannot be found. This is |
+| typically generated by ecsact_cpp_meta_header_codegen. Make sure the passed |
+| in template parameter (Decl) is an ecsact declaration type and the .meta.hh |
+| file is included in the source this method is being used.                   |
+ -----------------------------------------------------------------------------
+)");
+	return {};
+}
+
 } // namespace ecsact