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.

3 files changed, 190 insertions, 188 deletions

diff --git a/mrbgems/mruby-compiler/core/parse.y b/mrbgems/mruby-compiler/core/parse.y
index 637b04749..60cfeadae 100644
--- a/mrbgems/mruby-compiler/core/parse.y
+++ b/mrbgems/mruby-compiler/core/parse.y
@@ -3587,12 +3587,7 @@ var_ref         : variable
                     }
                 | keyword__ENCODING__
                     {
-#ifdef MRB_UTF8_STRING
-                      const char *enc = "UTF-8";
-#else
-                      const char *enc = "ASCII-8BIT";
-#endif
-                      $$ = new_str(p, enc, strlen(enc));
+                      $$ = new_fcall(p, MRB_SYM_2(p->mrb, __ENCODING__), 0);
                     }
                 ;
 
diff --git a/mrbgems/mruby-compiler/core/y.tab.c b/mrbgems/mruby-compiler/core/y.tab.c
index 2ae8890b6..4fa1b4678 100644
--- a/mrbgems/mruby-compiler/core/y.tab.c
+++ b/mrbgems/mruby-compiler/core/y.tab.c
@@ -2080,18 +2080,18 @@ static const yytype_int16 yyrline[] =
     3424,  3438,  3442,  3456,  3461,  3475,  3481,  3482,  3483,  3484,
     3485,  3489,  3495,  3499,  3509,  3510,  3511,  3515,  3521,  3525,
     3529,  3533,  3537,  3543,  3547,  3553,  3557,  3561,  3565,  3569,
-    3573,  3581,  3588,  3599,  3600,  3604,  3608,  3607,  3624,  3625,
-    3628,  3634,  3652,  3672,  3673,  3679,  3685,  3691,  3698,  3703,
-    3710,  3714,  3720,  3724,  3730,  3731,  3734,  3738,  3744,  3748,
-    3752,  3756,  3762,  3767,  3772,  3776,  3780,  3784,  3788,  3792,
-    3796,  3800,  3804,  3808,  3812,  3816,  3820,  3824,  3829,  3835,
-    3840,  3845,  3850,  3855,  3862,  3866,  3873,  3878,  3877,  3889,
-    3893,  3899,  3907,  3915,  3923,  3927,  3933,  3937,  3943,  3944,
-    3947,  3952,  3959,  3960,  3963,  3969,  3973,  3979,  3984,  3984,
-    4009,  4010,  4016,  4021,  4027,  4033,  4038,  4042,  4052,  4059,
-    4060,  4061,  4064,  4065,  4066,  4067,  4070,  4071,  4072,  4075,
-    4076,  4079,  4083,  4089,  4090,  4096,  4097,  4100,  4101,  4104,
-    4107,  4108,  4109,  4112,  4113,  4116,  4121,  4124,  4125,  4129
+    3573,  3581,  3588,  3594,  3595,  3599,  3603,  3602,  3619,  3620,
+    3623,  3629,  3647,  3667,  3668,  3674,  3680,  3686,  3693,  3698,
+    3705,  3709,  3715,  3719,  3725,  3726,  3729,  3733,  3739,  3743,
+    3747,  3751,  3757,  3762,  3767,  3771,  3775,  3779,  3783,  3787,
+    3791,  3795,  3799,  3803,  3807,  3811,  3815,  3819,  3824,  3830,
+    3835,  3840,  3845,  3850,  3857,  3861,  3868,  3873,  3872,  3884,
+    3888,  3894,  3902,  3910,  3918,  3922,  3928,  3932,  3938,  3939,
+    3942,  3947,  3954,  3955,  3958,  3964,  3968,  3974,  3979,  3979,
+    4004,  4005,  4011,  4016,  4022,  4028,  4033,  4037,  4047,  4054,
+    4055,  4056,  4059,  4060,  4061,  4062,  4065,  4066,  4067,  4070,
+    4071,  4074,  4078,  4084,  4085,  4091,  4092,  4095,  4096,  4099,
+    4102,  4103,  4104,  4107,  4108,  4111,  4116,  4119,  4120,  4124
 };
 #endif
 
@@ -9285,53 +9285,48 @@ yyreduce:
   case 492:
 #line 3589 "mrbgems/mruby-compiler/core/parse.y"
                     {
-#ifdef MRB_UTF8_STRING
-                      const char *enc = "UTF-8";
-#else
-                      const char *enc = "ASCII-8BIT";
-#endif
-                      (yyval.nd) = new_str(p, enc, strlen(enc));
+                      (yyval.nd) = new_fcall(p, MRB_SYM_2(p->mrb, __ENCODING__), 0);
                     }
-#line 9296 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9291 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 495:
-#line 3604 "mrbgems/mruby-compiler/core/parse.y"
+#line 3599 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = 0;
                     }
-#line 9304 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9299 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 496:
-#line 3608 "mrbgems/mruby-compiler/core/parse.y"
+#line 3603 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       p->lstate = EXPR_BEG;
                       p->cmd_start = TRUE;
                     }
-#line 9313 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9308 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 497:
-#line 3613 "mrbgems/mruby-compiler/core/parse.y"
+#line 3608 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = (yyvsp[-1].nd);
                     }
-#line 9321 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9316 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 500:
-#line 3629 "mrbgems/mruby-compiler/core/parse.y"
+#line 3624 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = (yyvsp[-1].nd);
                       p->lstate = EXPR_BEG;
                       p->cmd_start = TRUE;
                     }
-#line 9331 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9326 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 501:
-#line 3635 "mrbgems/mruby-compiler/core/parse.y"
+#line 3630 "mrbgems/mruby-compiler/core/parse.y"
                     {
 #if 1
                       /* til real keyword args implemented */
@@ -9349,11 +9344,11 @@ yyreduce:
                                     new_args_tail(p, 0, new_kw_rest_args(p, nsym(k)), b));
 #endif
                     }
-#line 9353 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9348 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 502:
-#line 3653 "mrbgems/mruby-compiler/core/parse.y"
+#line 3648 "mrbgems/mruby-compiler/core/parse.y"
                     {
 #if 1
                       /* til real keyword args implemented */
@@ -9371,504 +9366,504 @@ yyreduce:
                                     new_args_tail(p, 0, new_kw_rest_args(p, nsym(k)), b));
 #endif
                     }
-#line 9375 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9370 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 504:
-#line 3674 "mrbgems/mruby-compiler/core/parse.y"
+#line 3669 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = (yyvsp[-1].nd);
                     }
-#line 9383 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9378 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 505:
-#line 3680 "mrbgems/mruby-compiler/core/parse.y"
+#line 3675 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       local_nest(p);
                     }
-#line 9391 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9386 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 506:
-#line 3686 "mrbgems/mruby-compiler/core/parse.y"
+#line 3681 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       void_expr_error(p, (yyvsp[0].nd));
                       (yyval.nd) = new_kw_arg(p, (yyvsp[-1].id), cons((yyvsp[0].nd), locals_node(p)));
                       local_unnest(p);
                     }
-#line 9401 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9396 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 507:
-#line 3692 "mrbgems/mruby-compiler/core/parse.y"
+#line 3687 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_kw_arg(p, (yyvsp[0].id), 0);
                       local_unnest(p);
                     }
-#line 9410 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9405 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 508:
-#line 3699 "mrbgems/mruby-compiler/core/parse.y"
+#line 3694 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_kw_arg(p, (yyvsp[-1].id), cons((yyvsp[0].nd), locals_node(p)));
                       local_unnest(p);
                     }
-#line 9419 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9414 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 509:
-#line 3704 "mrbgems/mruby-compiler/core/parse.y"
+#line 3699 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_kw_arg(p, (yyvsp[0].id), 0);
                       local_unnest(p);
                     }
-#line 9428 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9423 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 510:
-#line 3711 "mrbgems/mruby-compiler/core/parse.y"
+#line 3706 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = list1((yyvsp[0].nd));
                     }
-#line 9436 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9431 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 511:
-#line 3715 "mrbgems/mruby-compiler/core/parse.y"
+#line 3710 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = push((yyvsp[-2].nd), (yyvsp[0].nd));
                     }
-#line 9444 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9439 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 512:
-#line 3721 "mrbgems/mruby-compiler/core/parse.y"
+#line 3716 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = list1((yyvsp[0].nd));
                     }
-#line 9452 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9447 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 513:
-#line 3725 "mrbgems/mruby-compiler/core/parse.y"
+#line 3720 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = push((yyvsp[-2].nd), (yyvsp[0].nd));
                     }
-#line 9460 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9455 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 516:
-#line 3735 "mrbgems/mruby-compiler/core/parse.y"
+#line 3730 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_kw_rest_args(p, nsym((yyvsp[0].id)));
                     }
-#line 9468 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9463 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 517:
-#line 3739 "mrbgems/mruby-compiler/core/parse.y"
+#line 3734 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_kw_rest_args(p, 0);
                     }
-#line 9476 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9471 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 518:
-#line 3745 "mrbgems/mruby-compiler/core/parse.y"
+#line 3740 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args_tail(p, (yyvsp[-3].nd), (yyvsp[-1].nd), (yyvsp[0].id));
                     }
-#line 9484 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9479 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 519:
-#line 3749 "mrbgems/mruby-compiler/core/parse.y"
+#line 3744 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args_tail(p, (yyvsp[-1].nd), 0, (yyvsp[0].id));
                     }
-#line 9492 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9487 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 520:
-#line 3753 "mrbgems/mruby-compiler/core/parse.y"
+#line 3748 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args_tail(p, 0, (yyvsp[-1].nd), (yyvsp[0].id));
                     }
-#line 9500 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9495 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 521:
-#line 3757 "mrbgems/mruby-compiler/core/parse.y"
+#line 3752 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args_tail(p, 0, 0, (yyvsp[0].id));
                     }
-#line 9508 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9503 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 522:
-#line 3763 "mrbgems/mruby-compiler/core/parse.y"
+#line 3758 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = (yyvsp[0].nd);
                     }
-#line 9516 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9511 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 523:
-#line 3767 "mrbgems/mruby-compiler/core/parse.y"
+#line 3762 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args_tail(p, 0, 0, 0);
                     }
-#line 9524 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9519 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 524:
-#line 3773 "mrbgems/mruby-compiler/core/parse.y"
+#line 3768 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, (yyvsp[-5].nd), (yyvsp[-3].nd), (yyvsp[-1].id), 0, (yyvsp[0].nd));
                     }
-#line 9532 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9527 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 525:
-#line 3777 "mrbgems/mruby-compiler/core/parse.y"
+#line 3772 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, (yyvsp[-7].nd), (yyvsp[-5].nd), (yyvsp[-3].id), (yyvsp[-1].nd), (yyvsp[0].nd));
                     }
-#line 9540 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9535 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 526:
-#line 3781 "mrbgems/mruby-compiler/core/parse.y"
+#line 3776 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, (yyvsp[-3].nd), (yyvsp[-1].nd), 0, 0, (yyvsp[0].nd));
                     }
-#line 9548 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9543 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 527:
-#line 3785 "mrbgems/mruby-compiler/core/parse.y"
+#line 3780 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, (yyvsp[-5].nd), (yyvsp[-3].nd), 0, (yyvsp[-1].nd), (yyvsp[0].nd));
                     }
-#line 9556 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9551 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 528:
-#line 3789 "mrbgems/mruby-compiler/core/parse.y"
+#line 3784 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, (yyvsp[-3].nd), 0, (yyvsp[-1].id), 0, (yyvsp[0].nd));
                     }
-#line 9564 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9559 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 529:
-#line 3793 "mrbgems/mruby-compiler/core/parse.y"
+#line 3788 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, (yyvsp[-5].nd), 0, (yyvsp[-3].id), (yyvsp[-1].nd), (yyvsp[0].nd));
                     }
-#line 9572 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9567 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 530:
-#line 3797 "mrbgems/mruby-compiler/core/parse.y"
+#line 3792 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, (yyvsp[-1].nd), 0, 0, 0, (yyvsp[0].nd));
                     }
-#line 9580 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9575 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 531:
-#line 3801 "mrbgems/mruby-compiler/core/parse.y"
+#line 3796 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, 0, (yyvsp[-3].nd), (yyvsp[-1].id), 0, (yyvsp[0].nd));
                     }
-#line 9588 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9583 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 532:
-#line 3805 "mrbgems/mruby-compiler/core/parse.y"
+#line 3800 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, 0, (yyvsp[-5].nd), (yyvsp[-3].id), (yyvsp[-1].nd), (yyvsp[0].nd));
                     }
-#line 9596 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9591 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 533:
-#line 3809 "mrbgems/mruby-compiler/core/parse.y"
+#line 3804 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, 0, (yyvsp[-1].nd), 0, 0, (yyvsp[0].nd));
                     }
-#line 9604 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9599 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 534:
-#line 3813 "mrbgems/mruby-compiler/core/parse.y"
+#line 3808 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, 0, (yyvsp[-3].nd), 0, (yyvsp[-1].nd), (yyvsp[0].nd));
                     }
-#line 9612 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9607 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 535:
-#line 3817 "mrbgems/mruby-compiler/core/parse.y"
+#line 3812 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, 0, 0, (yyvsp[-1].id), 0, (yyvsp[0].nd));
                     }
-#line 9620 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9615 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 536:
-#line 3821 "mrbgems/mruby-compiler/core/parse.y"
+#line 3816 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, 0, 0, (yyvsp[-3].id), (yyvsp[-1].nd), (yyvsp[0].nd));
                     }
-#line 9628 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9623 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 537:
-#line 3825 "mrbgems/mruby-compiler/core/parse.y"
+#line 3820 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_args(p, 0, 0, 0, 0, (yyvsp[0].nd));
                     }
-#line 9636 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9631 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 538:
-#line 3829 "mrbgems/mruby-compiler/core/parse.y"
+#line 3824 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       local_add_f(p, intern_op(and));
                       (yyval.nd) = new_args(p, 0, 0, 0, 0, 0);
                     }
-#line 9645 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9640 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 539:
-#line 3836 "mrbgems/mruby-compiler/core/parse.y"
+#line 3831 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       yyerror(p, "formal argument cannot be a constant");
                       (yyval.nd) = 0;
                     }
-#line 9654 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9649 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 540:
-#line 3841 "mrbgems/mruby-compiler/core/parse.y"
+#line 3836 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       yyerror(p, "formal argument cannot be an instance variable");
                       (yyval.nd) = 0;
                     }
-#line 9663 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9658 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 541:
-#line 3846 "mrbgems/mruby-compiler/core/parse.y"
+#line 3841 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       yyerror(p, "formal argument cannot be a global variable");
                       (yyval.nd) = 0;
                     }
-#line 9672 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9667 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 542:
-#line 3851 "mrbgems/mruby-compiler/core/parse.y"
+#line 3846 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       yyerror(p, "formal argument cannot be a class variable");
                       (yyval.nd) = 0;
                     }
-#line 9681 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9676 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 543:
-#line 3856 "mrbgems/mruby-compiler/core/parse.y"
+#line 3851 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       yyerror(p, "formal argument cannot be a numbered parameter");
                       (yyval.nd) = 0;
                     }
-#line 9690 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9685 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 544:
-#line 3863 "mrbgems/mruby-compiler/core/parse.y"
+#line 3858 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.id) = 0;
                     }
-#line 9698 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9693 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 545:
-#line 3867 "mrbgems/mruby-compiler/core/parse.y"
+#line 3862 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       local_add_f(p, (yyvsp[0].id));
                       (yyval.id) = (yyvsp[0].id);
                     }
-#line 9707 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9702 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 546:
-#line 3874 "mrbgems/mruby-compiler/core/parse.y"
+#line 3869 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_arg(p, (yyvsp[0].id));
                     }
-#line 9715 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9710 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 547:
-#line 3878 "mrbgems/mruby-compiler/core/parse.y"
+#line 3873 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = local_switch(p);
                     }
-#line 9723 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9718 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 548:
-#line 3882 "mrbgems/mruby-compiler/core/parse.y"
+#line 3877 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = new_masgn_param(p, (yyvsp[-1].nd), p->locals->car);
                       local_resume(p, (yyvsp[-2].nd));
                       local_add_f(p, 0);
                     }
-#line 9733 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9728 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 549:
-#line 3890 "mrbgems/mruby-compiler/core/parse.y"
+#line 3885 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = list1((yyvsp[0].nd));
                     }
-#line 9741 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9736 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 550:
-#line 3894 "mrbgems/mruby-compiler/core/parse.y"
+#line 3889 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = push((yyvsp[-2].nd), (yyvsp[0].nd));
                     }
-#line 9749 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9744 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 551:
-#line 3900 "mrbgems/mruby-compiler/core/parse.y"
+#line 3895 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       local_add_f(p, (yyvsp[-1].id));
                       local_nest(p);
                       (yyval.id) = (yyvsp[-1].id);
                     }
-#line 9759 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9754 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 552:
-#line 3908 "mrbgems/mruby-compiler/core/parse.y"
+#line 3903 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       void_expr_error(p, (yyvsp[0].nd));
                       (yyval.nd) = cons(nsym((yyvsp[-1].id)), cons((yyvsp[0].nd), locals_node(p)));
                       local_unnest(p);
                     }
-#line 9769 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9764 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 553:
-#line 3916 "mrbgems/mruby-compiler/core/parse.y"
+#line 3911 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       void_expr_error(p, (yyvsp[0].nd));
                       (yyval.nd) = cons(nsym((yyvsp[-1].id)), cons((yyvsp[0].nd), locals_node(p)));
                       local_unnest(p);
                     }
-#line 9779 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9774 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 554:
-#line 3924 "mrbgems/mruby-compiler/core/parse.y"
+#line 3919 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = list1((yyvsp[0].nd));
                     }
-#line 9787 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9782 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 555:
-#line 3928 "mrbgems/mruby-compiler/core/parse.y"
+#line 3923 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = push((yyvsp[-2].nd), (yyvsp[0].nd));
                     }
-#line 9795 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9790 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 556:
-#line 3934 "mrbgems/mruby-compiler/core/parse.y"
+#line 3929 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = list1((yyvsp[0].nd));
                     }
-#line 9803 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9798 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 557:
-#line 3938 "mrbgems/mruby-compiler/core/parse.y"
+#line 3933 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = push((yyvsp[-2].nd), (yyvsp[0].nd));
                     }
-#line 9811 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9806 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 560:
-#line 3948 "mrbgems/mruby-compiler/core/parse.y"
+#line 3943 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       local_add_f(p, (yyvsp[0].id));
                       (yyval.id) = (yyvsp[0].id);
                     }
-#line 9820 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9815 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 561:
-#line 3953 "mrbgems/mruby-compiler/core/parse.y"
+#line 3948 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       local_add_f(p, intern_op(mul));
                       (yyval.id) = -1;
                     }
-#line 9829 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9824 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 564:
-#line 3964 "mrbgems/mruby-compiler/core/parse.y"
+#line 3959 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.id) = (yyvsp[0].id);
                     }
-#line 9837 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9832 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 565:
-#line 3970 "mrbgems/mruby-compiler/core/parse.y"
+#line 3965 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.id) = (yyvsp[0].id);
                     }
-#line 9845 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9840 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 566:
-#line 3974 "mrbgems/mruby-compiler/core/parse.y"
+#line 3969 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.id) = 0;
                     }
-#line 9853 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9848 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 567:
-#line 3980 "mrbgems/mruby-compiler/core/parse.y"
+#line 3975 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = (yyvsp[0].nd);
                       if (!(yyval.nd)) (yyval.nd) = new_nil(p);
                     }
-#line 9862 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9857 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 568:
-#line 3984 "mrbgems/mruby-compiler/core/parse.y"
+#line 3979 "mrbgems/mruby-compiler/core/parse.y"
                       {p->lstate = EXPR_BEG;}
-#line 9868 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9863 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 569:
-#line 3985 "mrbgems/mruby-compiler/core/parse.y"
+#line 3980 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       if ((yyvsp[-1].nd) == 0) {
                         yyerror(p, "can't define singleton method for ().");
@@ -9891,63 +9886,63 @@ yyreduce:
                       }
                       (yyval.nd) = (yyvsp[-1].nd);
                     }
-#line 9895 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9890 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 571:
-#line 4011 "mrbgems/mruby-compiler/core/parse.y"
+#line 4006 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = (yyvsp[-1].nd);
                     }
-#line 9903 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9898 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 572:
-#line 4017 "mrbgems/mruby-compiler/core/parse.y"
+#line 4012 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = list1((yyvsp[0].nd));
                       NODE_LINENO((yyval.nd), (yyvsp[0].nd));
                     }
-#line 9912 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9907 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 573:
-#line 4022 "mrbgems/mruby-compiler/core/parse.y"
+#line 4017 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = push((yyvsp[-2].nd), (yyvsp[0].nd));
                     }
-#line 9920 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9915 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 574:
-#line 4028 "mrbgems/mruby-compiler/core/parse.y"
+#line 4023 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       void_expr_error(p, (yyvsp[-2].nd));
                       void_expr_error(p, (yyvsp[0].nd));
                       (yyval.nd) = cons((yyvsp[-2].nd), (yyvsp[0].nd));
                     }
-#line 9930 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9925 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 575:
-#line 4034 "mrbgems/mruby-compiler/core/parse.y"
+#line 4029 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       void_expr_error(p, (yyvsp[0].nd));
                       (yyval.nd) = cons(new_sym(p, (yyvsp[-2].id)), (yyvsp[0].nd));
                     }
-#line 9939 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9934 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 576:
-#line 4039 "mrbgems/mruby-compiler/core/parse.y"
+#line 4034 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = cons(new_sym(p, (yyvsp[-1].id)), label_reference(p, (yyvsp[-1].id)));
                     }
-#line 9947 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9942 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 577:
-#line 4043 "mrbgems/mruby-compiler/core/parse.y"
+#line 4038 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       void_expr_error(p, (yyvsp[0].nd));
                       if (typen((yyvsp[-2].nd)->car) == NODE_DSTR) {
@@ -9957,67 +9952,67 @@ yyreduce:
                         (yyval.nd) = cons(new_sym(p, new_strsym(p, (yyvsp[-2].nd))), (yyvsp[0].nd));
                       }
                     }
-#line 9961 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9956 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 578:
-#line 4053 "mrbgems/mruby-compiler/core/parse.y"
+#line 4048 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       void_expr_error(p, (yyvsp[0].nd));
                       (yyval.nd) = cons(new_kw_rest_args(p, 0), (yyvsp[0].nd));
                     }
-#line 9970 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9965 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 591:
-#line 4080 "mrbgems/mruby-compiler/core/parse.y"
+#line 4075 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.num) = '.';
                     }
-#line 9978 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9973 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 592:
-#line 4084 "mrbgems/mruby-compiler/core/parse.y"
+#line 4079 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.num) = 0;
                     }
-#line 9986 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9981 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 594:
-#line 4091 "mrbgems/mruby-compiler/core/parse.y"
+#line 4086 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.num) = tCOLON2;
                     }
-#line 9994 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9989 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 603:
-#line 4112 "mrbgems/mruby-compiler/core/parse.y"
+#line 4107 "mrbgems/mruby-compiler/core/parse.y"
                       {yyerrok;}
-#line 10000 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 9995 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 605:
-#line 4117 "mrbgems/mruby-compiler/core/parse.y"
+#line 4112 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       p->lineno += (yyvsp[0].num);
                       p->column = 0;
                     }
-#line 10009 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 10004 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
   case 609:
-#line 4129 "mrbgems/mruby-compiler/core/parse.y"
+#line 4124 "mrbgems/mruby-compiler/core/parse.y"
                     {
                       (yyval.nd) = 0;
                     }
-#line 10017 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 10012 "mrbgems/mruby-compiler/core/y.tab.c"
     break;
 
 
-#line 10021 "mrbgems/mruby-compiler/core/y.tab.c"
+#line 10016 "mrbgems/mruby-compiler/core/y.tab.c"
 
       default: break;
     }
@@ -10249,7 +10244,7 @@ yyreturn:
 #endif
   return yyresult;
 }
-#line 4133 "mrbgems/mruby-compiler/core/parse.y"
+#line 4128 "mrbgems/mruby-compiler/core/parse.y"
 
 #define pylval  (*((YYSTYPE*)(p->ylval)))
 
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);
 }