define Module#const_missing

1 files changed, 13 insertions, 0 deletions

diff --git a/src/class.c b/src/class.c
index 84c6964e2..a7d77924f 100644
--- a/src/class.c
+++ b/src/class.c
@@ -1833,6 +1833,18 @@ mrb_mod_remove_const(mrb_state *mrb, mrb_value mod)
   return val;
 }
 
+mrb_value
+mrb_mod_const_missing(mrb_state *mrb, mrb_value mod)
+{
+  mrb_sym sym;
+
+  mrb_get_args(mrb, "n", &sym);
+  mrb_name_error(mrb, sym, "uninitialized constant %S",
+                 mrb_sym2str(mrb, sym));
+  /* not reached */
+  return mrb_nil_value();
+}
+
 static mrb_value
 mrb_mod_s_constants(mrb_state *mrb, mrb_value mod)
 {
@@ -1926,6 +1938,7 @@ mrb_init_class(mrb_state *mrb)
   mrb_define_method(mrb, mod, "const_set",               mrb_mod_const_set,        MRB_ARGS_REQ(2)); /* 15.2.2.4.23 */
   mrb_define_method(mrb, mod, "constants",               mrb_mod_constants,        MRB_ARGS_NONE()); /* 15.2.2.4.24 */
   mrb_define_method(mrb, mod, "remove_const",            mrb_mod_remove_const,     MRB_ARGS_REQ(1)); /* 15.2.2.4.40 */
+  mrb_define_method(mrb, mod, "const_missing",           mrb_mod_const_missing,    MRB_ARGS_REQ(1));
   mrb_define_method(mrb, mod, "define_method",           mod_define_method,        MRB_ARGS_REQ(1));
   mrb_define_method(mrb, mod, "class_variables",         mrb_mod_class_variables,  MRB_ARGS_NONE()); /* 15.2.2.4.19 */
   mrb_define_method(mrb, mod, "===",                     mrb_mod_eqq,              MRB_ARGS_REQ(1));