Added mrb_class_under_defined

2 files changed, 41 insertions, 0 deletions

diff --git a/include/mruby.h b/include/mruby.h
index 25514ee2c..a603a316d 100644
--- a/include/mruby.h
+++ b/include/mruby.h
@@ -567,6 +567,37 @@ MRB_API mrb_bool mrb_class_defined(mrb_state *mrb, const char *name);
 MRB_API struct RClass * mrb_class_get(mrb_state *mrb, const char *name);
 
 /**
+ * Returns an mrb_bool. True if child class was defined, and false if the child class was not defined.
+ *
+ * Example:
+ *     void
+ *     mrb_example_gem_init(mrb_state* mrb) {
+ *       struct RClass *example_parent, *example_child;
+ *       mrb_bool cd;
+ *
+ *       example_parent = mrb_define_module(mrb, "ExampleParent");
+ *
+ *       example_child = mrb_define_class(mrb, "ExampleChild", mrb->object_class);
+ *       cd = mrb_class_under_defined(mrb, example_parent, "ExampleChild");
+ *
+ *       // If mrb_class_under_defined returns 1 then puts "True"
+ *       // If mrb_class_under_defined returns 0 then puts "False"
+ *       if (cd == 1){
+ *         puts("True");
+ *       }
+ *       else {
+ *         puts("False");
+ *       }
+ *      }
+ *
+ * @param [mrb_state*] mrb The current mruby state.
+ * @param [struct RClass *] outer The name of the parent class.
+ * @param [const char *] name A string representing the name of the child class.
+ * @return [mrb_bool] A boolean value.
+ */
+MRB_API mrb_bool mrb_class_under_defined(mrb_state *mrb, struct RClass *outer, const char *name);
+
+/**
  * Gets a child class.
  * @param [mrb_state*] mrb The current mruby state.
  * @param [struct RClass *] outer The name of the parent class.
diff --git a/src/class.c b/src/class.c
index 47a6c846b..ed2e5d5ba 100644
--- a/src/class.c
+++ b/src/class.c
@@ -271,6 +271,16 @@ mrb_class_defined(mrb_state *mrb, const char *name)
   return mrb_const_defined(mrb, mrb_obj_value(mrb->object_class), mrb_symbol(sym));
 }
 
+MRB_API mrb_bool
+mrb_class_under_defined(mrb_state *mrb, struct RClass *outer, const char *name)
+{
+  mrb_value sym = mrb_check_intern_cstr(mrb, name);
+  if (mrb_nil_p(sym)) {
+    return FALSE;
+  }
+  return mrb_const_defined_at(mrb, mrb_obj_value(outer), mrb_symbol(sym));
+}
+
 MRB_API struct RClass *
 mrb_class_get_under(mrb_state *mrb, struct RClass *outer, const char *name)
 {