parse.y: `__ENCODING__` should be determined in run-time; fix #5552

It used to be compiled to the static string in the compiler. But the
encoding status actually depends on the runtime configuration. A new
method `Kernel#__ENCODING__` is introduced to implement the feature.

1 files changed, 13 insertions, 1 deletions

diff --git a/src/kernel.c b/src/kernel.c
index ab6f37e72..f8ef1bfe1 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -612,6 +612,17 @@ mrb_obj_ceqq(mrb_state *mrb, mrb_value self)
   return mrb_false_value();
 }
 
+static mrb_value
+mrb_encoding(mrb_state *mrb, mrb_value self)
+{
+  mrb_get_args(mrb, "");
+#ifdef MRB_UTF8_STRING
+  return mrb_str_new_lit(mrb, "UTF-8");
+#else
+  return mrb_str_new_lit(mrb, "ASCII-8BIT");
+#endif
+}
+
 mrb_value mrb_obj_equal_m(mrb_state *mrb, mrb_value);
 
 void
@@ -651,7 +662,8 @@ mrb_init_kernel(mrb_state *mrb)
   mrb_define_method(mrb, krn, "respond_to?",                obj_respond_to,                  MRB_ARGS_ARG(1,1));     /* 15.3.1.3.43 */
   mrb_define_method(mrb, krn, "to_s",                       mrb_any_to_s,                    MRB_ARGS_NONE());    /* 15.3.1.3.46 */
   mrb_define_method(mrb, krn, "__case_eqq",                 mrb_obj_ceqq,                    MRB_ARGS_REQ(1));    /* internal */
-  mrb_define_method(mrb, krn, "__to_int",                   mrb_to_integer,                  MRB_ARGS_NONE()); /* internal */
+  mrb_define_method(mrb, krn, "__to_int",                   mrb_to_integer,                  MRB_ARGS_NONE());    /* internal */
+  mrb_define_method(mrb, krn, "__ENCODING__",               mrb_encoding,                    MRB_ARGS_NONE());
 
   mrb_include_module(mrb, mrb->object_class, mrb->kernel_module);
 }