add method example

manuals/meta_examples/methods_example.cpp

@@ -8,8 +8,73 @@
 
 namespace
 {
+    struct ivec2 {
+        int x{};
+        int y{};
+
+        ivec2& add(const ivec2& other) {
+            x += other.x;
+            y += other.y;
+            return *this;
+        }
+
+        friend bool operator==(const ivec2& l, const ivec2& r) {
+            return l.x == r.x && l.y == r.y;
+        }
+    };
 }
 
-TEST_CASE("meta/meta_examples/methods") {
+TEST_CASE("meta/meta_examples/methods/type") {
     namespace meta = meta_hpp;
+
+    // 'ivec2' class type registration
+    meta::class_<ivec2>()
+        .method_("add", &ivec2::add);
+
+    // resolves a method type by pointer
+    const meta::method_type add_method_type = meta::resolve_type(&ivec2::add);
+
+    // also, it can be resolved by static method type
+    CHECK(add_method_type == meta::resolve_type<ivec2&(ivec2::*)(const ivec2&)>());
+
+    // allows to know the owner class type
+    CHECK(add_method_type.get_owner_type() == meta::resolve_type<ivec2>());
+
+    // checks a return value type
+    CHECK(add_method_type.get_return_type() == meta::resolve_type<ivec2&>());
+
+    // allows to know an argument count
+    CHECK(add_method_type.get_arity() == 1);
+
+    // ... and their types
+    CHECK(add_method_type.get_argument_type(0) == meta::resolve_type<const ivec2&>());
+}
+
+TEST_CASE("meta/meta_examples/methods/usage") {
+    namespace meta = meta_hpp;
+
+    ivec2 v{20, 10};
+
+    // resolves a class type by instance 'v'
+    const meta::class_type ivec2_type = meta::resolve_type(v);
+
+    // finds the method 'add' by name
+    const meta::method ivec2_add = ivec2_type.get_method("add");
+
+    // checks the type of the method 'add'
+    CHECK(ivec2_add.get_type() == meta::resolve_type<ivec2&(ivec2::*)(const ivec2&)>());
+
+    // checks the ability to call the method with specific parameters
+    CHECK(ivec2_add.is_invocable_with(v, ivec2{22, 11}));
+    CHECK(ivec2_add.is_invocable_with<ivec2&, ivec2>());
+
+    // calls the method and retrieves a returned value
+    const meta::value ivec2_add_result_value = ivec2_add.invoke(v, ivec2{22, 11}).value();
+
+    // checks the type and value of the result
+    CHECK(ivec2_add_result_value.get_type() == meta::resolve_type<ivec2>());
+    CHECK(ivec2_add_result_value == ivec2{42, 21});
+
+    // checks the result of our manipulations
+    CHECK(v == ivec2{42, 21});
 }