Separate meta-programming features to `mruby-metaprog` gem.

We assume meta-programming is less used in embedded environments.
We have moved following methods:

 * Kernel module
   global_variables, local_variables, singleton_class,
   instance_variables, instance_variables_defined?, instance_variable_get,
   instance_variable_set, methods, private_methods, public_methods,
   protected_methods, singleton_methods, define_singleton_methods

 * Module class
   class_variables, class_variables_defined?, class_variable_get,
   class_variable_set, remove_class_variable, included_modules,
   instance_methods, remove_method, method_removed, constants

 * Module class methods
   constants, nesting

Note:
Following meta-programming methods are kept in the core:

 * Module class
   alias_method, undef_method, ancestors, const_defined?, const_get,
   const_set, remove_const, method_defined?, define_method

 * Toplevel object
   define_method

`mruby-metaprog` gem is linked by default (specified in default.gembox).
When it is removed, it will save 40KB (stripped:8KB) on x86-64
environment last time I measured.

11 files changed, 1030 insertions, 15 deletions

diff --git a/mrbgems/default.gembox b/mrbgems/default.gembox
index 7ddbb16d1..23e65fcee 100644
--- a/mrbgems/default.gembox
+++ b/mrbgems/default.gembox
@@ -1,4 +1,7 @@
 MRuby::GemBox.new do |conf|
+  # Meta-programming features
+  conf.gem :core => "mruby-metaprog"
+
   # Use standard IO/File class
   conf.gem :core => "mruby-io"
 
diff --git a/mrbgems/mruby-bin-strip/bintest/mruby-strip.rb b/mrbgems/mruby-bin-strip/bintest/mruby-strip.rb
index bb664a2b1..2db3c10b1 100644
--- a/mrbgems/mruby-bin-strip/bintest/mruby-strip.rb
+++ b/mrbgems/mruby-bin-strip/bintest/mruby-strip.rb
@@ -67,7 +67,7 @@ EOS
 
   `#{cmd('mruby-strip')} -l #{without_lv.path}`
   assert_true without_lv.size < with_lv.size
-
-  assert_equal '[:a, :b]', `#{cmd('mruby')} -b #{with_lv.path}`.chomp
-  assert_equal '[]', `#{cmd('mruby')} -b #{without_lv.path}`.chomp
+#
+#  assert_equal '[:a, :b]', `#{cmd('mruby')} -b #{with_lv.path}`.chomp
+#  assert_equal '[]', `#{cmd('mruby')} -b #{without_lv.path}`.chomp
 end
diff --git a/mrbgems/mruby-class-ext/test/module.rb b/mrbgems/mruby-class-ext/test/module.rb
index ed6713aac..71a8da451 100644
--- a/mrbgems/mruby-class-ext/test/module.rb
+++ b/mrbgems/mruby-class-ext/test/module.rb
@@ -26,7 +26,7 @@ end
 assert 'Module#singleton_class?' do
   mod = Module.new
   cls = Class.new
-  scl = cls.singleton_class
+  scl = (class <<cls; self; end)
 
   assert_false mod.singleton_class?
   assert_false cls.singleton_class?
diff --git a/mrbgems/mruby-eval/test/eval.rb b/mrbgems/mruby-eval/test/eval.rb
index 8cf658f29..a710a1fc0 100644
--- a/mrbgems/mruby-eval/test/eval.rb
+++ b/mrbgems/mruby-eval/test/eval.rb
@@ -58,7 +58,7 @@ end
 
 assert('String instance_eval') do
   obj = Object.new
-  obj.instance_variable_set :@test, 'test'
+  obj.instance_eval{ @test = 'test' }
   assert_raise(ArgumentError) { obj.instance_eval(0) { } }
   assert_raise(ArgumentError) { obj.instance_eval('0', 'test', 0, 'test') }
   assert_equal(['test.rb', 10]) { obj.instance_eval('[__FILE__, __LINE__]', 'test.rb', 10)}
diff --git a/mrbgems/mruby-io/test/io.rb b/mrbgems/mruby-io/test/io.rb
index e06b14996..48a74f31e 100644
--- a/mrbgems/mruby-io/test/io.rb
+++ b/mrbgems/mruby-io/test/io.rb
@@ -35,7 +35,7 @@ assert('IO', '15.2.20.2') do
 end
 
 assert('IO', '15.2.20.3') do
-  assert_include(IO.included_modules, Enumerable)
+  assert_include(IO.ancestors, Enumerable)
 end
 
 assert('IO.open', '15.2.20.4.1') do
diff --git a/mrbgems/mruby-metaprog/mrbgem.rake b/mrbgems/mruby-metaprog/mrbgem.rake
new file mode 100644
index 000000000..1b81d6345
--- /dev/null
+++ b/mrbgems/mruby-metaprog/mrbgem.rake
@@ -0,0 +1,5 @@
+MRuby::Gem::Specification.new('mruby-metaprog') do |spec|
+  spec.license = 'MIT'
+  spec.author  = 'mruby developers'
+  spec.summary = 'Meta-programming features for mruby'
+end
diff --git a/mrbgems/mruby-metaprog/src/metaprog.c b/mrbgems/mruby-metaprog/src/metaprog.c
new file mode 100644
index 000000000..18003ef4d
--- /dev/null
+++ b/mrbgems/mruby-metaprog/src/metaprog.c
@@ -0,0 +1,701 @@
+#include "mruby.h"
+#include "mruby/array.h"
+#include "mruby/hash.h"
+#include "mruby/variable.h"
+#include "mruby/proc.h"
+#include "mruby/class.h"
+#include "mruby/string.h"
+
+typedef enum {
+  NOEX_PUBLIC    = 0x00,
+  NOEX_NOSUPER   = 0x01,
+  NOEX_PRIVATE   = 0x02,
+  NOEX_PROTECTED = 0x04,
+  NOEX_MASK      = 0x06,
+  NOEX_BASIC     = 0x08,
+  NOEX_UNDEF     = NOEX_NOSUPER,
+  NOEX_MODFUNC   = 0x12,
+  NOEX_SUPER     = 0x20,
+  NOEX_VCALL     = 0x40,
+  NOEX_RESPONDS  = 0x80
+} mrb_method_flag_t;
+
+static mrb_value
+mrb_f_nil(mrb_state *mrb, mrb_value cv)
+{
+  return mrb_nil_value();
+}
+
+/* 15.3.1.3.20 */
+/*
+ *  call-seq:
+ *     obj.instance_variable_defined?(symbol)    -> true or false
+ *
+ *  Returns <code>true</code> if the given instance variable is
+ *  defined in <i>obj</i>.
+ *
+ *     class Fred
+ *       def initialize(p1, p2)
+ *         @a, @b = p1, p2
+ *       end
+ *     end
+ *     fred = Fred.new('cat', 99)
+ *     fred.instance_variable_defined?(:@a)    #=> true
+ *     fred.instance_variable_defined?("@b")   #=> true
+ *     fred.instance_variable_defined?("@c")   #=> false
+ */
+static mrb_value
+mrb_obj_ivar_defined(mrb_state *mrb, mrb_value self)
+{
+  mrb_sym sym;
+
+  mrb_get_args(mrb, "n", &sym);
+  mrb_iv_name_sym_check(mrb, sym);
+  return mrb_bool_value(mrb_iv_defined(mrb, self, sym));
+}
+
+/* 15.3.1.3.21 */
+/*
+ *  call-seq:
+ *     obj.instance_variable_get(symbol)    -> obj
+ *
+ *  Returns the value of the given instance variable, or nil if the
+ *  instance variable is not set. The <code>@</code> part of the
+ *  variable name should be included for regular instance
+ *  variables. Throws a <code>NameError</code> exception if the
+ *  supplied symbol is not valid as an instance variable name.
+ *
+ *     class Fred
+ *       def initialize(p1, p2)
+ *         @a, @b = p1, p2
+ *       end
+ *     end
+ *     fred = Fred.new('cat', 99)
+ *     fred.instance_variable_get(:@a)    #=> "cat"
+ *     fred.instance_variable_get("@b")   #=> 99
+ */
+static mrb_value
+mrb_obj_ivar_get(mrb_state *mrb, mrb_value self)
+{
+  mrb_sym iv_name;
+
+  mrb_get_args(mrb, "n", &iv_name);
+  mrb_iv_name_sym_check(mrb, iv_name);
+  return mrb_iv_get(mrb, self, iv_name);
+}
+
+/* 15.3.1.3.22 */
+/*
+ *  call-seq:
+ *     obj.instance_variable_set(symbol, obj)    -> obj
+ *
+ *  Sets the instance variable names by <i>symbol</i> to
+ *  <i>object</i>, thereby frustrating the efforts of the class's
+ *  author to attempt to provide proper encapsulation. The variable
+ *  did not have to exist prior to this call.
+ *
+ *     class Fred
+ *       def initialize(p1, p2)
+ *         @a, @b = p1, p2
+ *       end
+ *     end
+ *     fred = Fred.new('cat', 99)
+ *     fred.instance_variable_set(:@a, 'dog')   #=> "dog"
+ *     fred.instance_variable_set(:@c, 'cat')   #=> "cat"
+ *     fred.inspect                             #=> "#<Fred:0x401b3da8 @a=\"dog\", @b=99, @c=\"cat\">"
+ */
+static mrb_value
+mrb_obj_ivar_set(mrb_state *mrb, mrb_value self)
+{
+  mrb_sym iv_name;
+  mrb_value val;
+
+  mrb_get_args(mrb, "no", &iv_name, &val);
+  mrb_iv_name_sym_check(mrb, iv_name);
+  mrb_iv_set(mrb, self, iv_name, val);
+  return val;
+}
+
+/* 15.3.1.2.7 */
+/*
+ *  call-seq:
+ *     local_variables   -> array
+ *
+ *  Returns the names of local variables in the current scope.
+ *
+ *  [mruby limitation]
+ *  If variable symbol information was stripped out from
+ *  compiled binary files using `mruby-strip -l`, this
+ *  method always returns an empty array.
+ */
+static mrb_value
+mrb_local_variables(mrb_state *mrb, mrb_value self)
+{
+  struct RProc *proc;
+  mrb_irep *irep;
+  mrb_value vars;
+  size_t i;
+
+  proc = mrb->c->ci[-1].proc;
+
+  if (MRB_PROC_CFUNC_P(proc)) {
+    return mrb_ary_new(mrb);
+  }
+  vars = mrb_hash_new(mrb);
+  while (proc) {
+    if (MRB_PROC_CFUNC_P(proc)) break;
+    irep = proc->body.irep;
+    if (!irep->lv) break;
+    for (i = 0; i + 1 < irep->nlocals; ++i) {
+      if (irep->lv[i].name) {
+        mrb_sym sym = irep->lv[i].name;
+        const char *name = mrb_sym2name(mrb, sym);
+        switch (name[0]) {
+        case '*': case '&':
+          break;
+        default:
+          mrb_hash_set(mrb, vars, mrb_symbol_value(sym), mrb_true_value());
+          break;
+        }
+      }
+    }
+    if (!MRB_PROC_ENV_P(proc)) break;
+    proc = proc->upper;
+    //if (MRB_PROC_SCOPE_P(proc)) break;
+    if (!proc->c) break;
+  }
+
+  return mrb_hash_keys(mrb, vars);
+}
+
+KHASH_DECLARE(st, mrb_sym, char, FALSE)
+
+static void
+method_entry_loop(mrb_state *mrb, struct RClass* klass, khash_t(st)* set)
+{
+  khint_t i;
+
+  khash_t(mt) *h = klass->mt;
+  if (!h || kh_size(h) == 0) return;
+  for (i=0;i<kh_end(h);i++) {
+    if (kh_exist(h, i)) {
+      mrb_method_t m = kh_value(h, i);
+      if (MRB_METHOD_UNDEF_P(m)) continue;
+      kh_put(st, mrb, set, kh_key(h, i));
+    }
+  }
+}
+
+mrb_value
+mrb_class_instance_method_list(mrb_state *mrb, mrb_bool recur, struct RClass* klass, int obj)
+{
+  khint_t i;
+  mrb_value ary;
+  mrb_bool prepended = FALSE;
+  struct RClass* oldklass;
+  khash_t(st)* set = kh_init(st, mrb);
+
+  if (!recur && (klass->flags & MRB_FL_CLASS_IS_PREPENDED)) {
+    MRB_CLASS_ORIGIN(klass);
+    prepended = TRUE;
+  }
+
+  oldklass = 0;
+  while (klass && (klass != oldklass)) {
+    method_entry_loop(mrb, klass, set);
+    if ((klass->tt == MRB_TT_ICLASS && !prepended) ||
+        (klass->tt == MRB_TT_SCLASS)) {
+    }
+    else {
+      if (!recur) break;
+    }
+    oldklass = klass;
+    klass = klass->super;
+  }
+
+  ary = mrb_ary_new_capa(mrb, kh_size(set));
+  for (i=0;i<kh_end(set);i++) {
+    if (kh_exist(set, i)) {
+      mrb_ary_push(mrb, ary, mrb_symbol_value(kh_key(set, i)));
+    }
+  }
+  kh_destroy(st, mrb, set);
+
+  return ary;
+}
+
+static mrb_value
+mrb_obj_methods(mrb_state *mrb, mrb_bool recur, mrb_value obj, mrb_method_flag_t flag)
+{
+  return mrb_class_instance_method_list(mrb, recur, mrb_class(mrb, obj), 0);
+}
+/* 15.3.1.3.31 */
+/*
+ *  call-seq:
+ *     obj.methods    -> array
+ *
+ *  Returns a list of the names of methods publicly accessible in
+ *  <i>obj</i>. This will include all the methods accessible in
+ *  <i>obj</i>'s ancestors.
+ *
+ *     class Klass
+ *       def kMethod()
+ *       end
+ *     end
+ *     k = Klass.new
+ *     k.methods[0..9]    #=> [:kMethod, :respond_to?, :nil?, :is_a?,
+ *                        #    :class, :instance_variable_set,
+ *                        #    :methods, :extend, :__send__, :instance_eval]
+ *     k.methods.length   #=> 42
+ */
+static mrb_value
+mrb_obj_methods_m(mrb_state *mrb, mrb_value self)
+{
+  mrb_bool recur = TRUE;
+  mrb_get_args(mrb, "|b", &recur);
+  return mrb_obj_methods(mrb, recur, self, (mrb_method_flag_t)0); /* everything but private */
+}
+
+/* 15.3.1.3.36 */
+/*
+ *  call-seq:
+ *     obj.private_methods(all=true)   -> array
+ *
+ *  Returns the list of private methods accessible to <i>obj</i>. If
+ *  the <i>all</i> parameter is set to <code>false</code>, only those methods
+ *  in the receiver will be listed.
+ */
+static mrb_value
+mrb_obj_private_methods(mrb_state *mrb, mrb_value self)
+{
+  mrb_bool recur = TRUE;
+  mrb_get_args(mrb, "|b", &recur);
+  return mrb_obj_methods(mrb, recur, self, NOEX_PRIVATE); /* private attribute not define */
+}
+
+/* 15.3.1.3.37 */
+/*
+ *  call-seq:
+ *     obj.protected_methods(all=true)   -> array
+ *
+ *  Returns the list of protected methods accessible to <i>obj</i>. If
+ *  the <i>all</i> parameter is set to <code>false</code>, only those methods
+ *  in the receiver will be listed.
+ */
+static mrb_value
+mrb_obj_protected_methods(mrb_state *mrb, mrb_value self)
+{
+  mrb_bool recur = TRUE;
+  mrb_get_args(mrb, "|b", &recur);
+  return mrb_obj_methods(mrb, recur, self, NOEX_PROTECTED); /* protected attribute not define */
+}
+
+/* 15.3.1.3.38 */
+/*
+ *  call-seq:
+ *     obj.public_methods(all=true)   -> array
+ *
+ *  Returns the list of public methods accessible to <i>obj</i>. If
+ *  the <i>all</i> parameter is set to <code>false</code>, only those methods
+ *  in the receiver will be listed.
+ */
+static mrb_value
+mrb_obj_public_methods(mrb_state *mrb, mrb_value self)
+{
+  mrb_bool recur = TRUE;
+  mrb_get_args(mrb, "|b", &recur);
+  return mrb_obj_methods(mrb, recur, self, NOEX_PUBLIC); /* public attribute not define */
+}
+
+static mrb_value
+mrb_obj_singleton_methods(mrb_state *mrb, mrb_bool recur, mrb_value obj)
+{
+  khint_t i;
+  mrb_value ary;
+  struct RClass* klass;
+  khash_t(st)* set = kh_init(st, mrb);
+
+  klass = mrb_class(mrb, obj);
+
+  if (klass && (klass->tt == MRB_TT_SCLASS)) {
+      method_entry_loop(mrb, klass, set);
+      klass = klass->super;
+  }
+  if (recur) {
+      while (klass && ((klass->tt == MRB_TT_SCLASS) || (klass->tt == MRB_TT_ICLASS))) {
+        method_entry_loop(mrb, klass, set);
+        klass = klass->super;
+      }
+  }
+
+  ary = mrb_ary_new(mrb);
+  for (i=0;i<kh_end(set);i++) {
+    if (kh_exist(set, i)) {
+      mrb_ary_push(mrb, ary, mrb_symbol_value(kh_key(set, i)));
+    }
+  }
+  kh_destroy(st, mrb, set);
+
+  return ary;
+}
+
+/* 15.3.1.3.45 */
+/*
+ *  call-seq:
+ *     obj.singleton_methods(all=true)    -> array
+ *
+ *  Returns an array of the names of singleton methods for <i>obj</i>.
+ *  If the optional <i>all</i> parameter is true, the list will include
+ *  methods in modules included in <i>obj</i>.
+ *  Only public and protected singleton methods are returned.
+ *
+ *     module Other
+ *       def three() end
+ *     end
+ *
+ *     class Single
+ *       def Single.four() end
+ *     end
+ *
+ *     a = Single.new
+ *
+ *     def a.one()
+ *     end
+ *
+ *     class << a
+ *       include Other
+ *       def two()
+ *       end
+ *     end
+ *
+ *     Single.singleton_methods    #=> [:four]
+ *     a.singleton_methods(false)  #=> [:two, :one]
+ *     a.singleton_methods         #=> [:two, :one, :three]
+ */
+static mrb_value
+mrb_obj_singleton_methods_m(mrb_state *mrb, mrb_value self)
+{
+  mrb_bool recur = TRUE;
+  mrb_get_args(mrb, "|b", &recur);
+  return mrb_obj_singleton_methods(mrb, recur, self);
+}
+
+static mrb_value
+mod_define_singleton_method(mrb_state *mrb, mrb_value self)
+{
+  struct RProc *p;
+  mrb_method_t m;
+  mrb_sym mid;
+  mrb_value blk = mrb_nil_value();
+
+  mrb_get_args(mrb, "n&", &mid, &blk);
+  if (mrb_nil_p(blk)) {
+    mrb_raise(mrb, E_ARGUMENT_ERROR, "no block given");
+  }
+  p = (struct RProc*)mrb_obj_alloc(mrb, MRB_TT_PROC, mrb->proc_class);
+  mrb_proc_copy(p, mrb_proc_ptr(blk));
+  p->flags |= MRB_PROC_STRICT;
+  MRB_METHOD_FROM_PROC(m, p);
+  mrb_define_method_raw(mrb, mrb_class_ptr(mrb_singleton_class(mrb, self)), mid, m);
+  return mrb_symbol_value(mid);
+}
+
+static void
+check_cv_name_str(mrb_state *mrb, mrb_value str)
+{
+  const char *s = RSTRING_PTR(str);
+  mrb_int len = RSTRING_LEN(str);
+
+  if (len < 3 || !(s[0] == '@' && s[1] == '@')) {
+    mrb_name_error(mrb, mrb_intern_str(mrb, str), "'%S' is not allowed as a class variable name", str);
+  }
+}
+
+static void
+check_cv_name_sym(mrb_state *mrb, mrb_sym id)
+{
+  check_cv_name_str(mrb, mrb_sym2str(mrb, id));
+}
+
+/* 15.2.2.4.39 */
+/*
+ *  call-seq:
+ *     remove_class_variable(sym)    -> obj
+ *
+ *  Removes the definition of the <i>sym</i>, returning that
+ *  constant's value.
+ *
+ *     class Dummy
+ *       @@var = 99
+ *       puts @@var
+ *       p class_variables
+ *       remove_class_variable(:@@var)
+ *       p class_variables
+ *     end
+ *
+ *  <em>produces:</em>
+ *
+ *     99
+ *     [:@@var]
+ *     []
+ */
+
+static mrb_value
+mrb_mod_remove_cvar(mrb_state *mrb, mrb_value mod)
+{
+  mrb_value val;
+  mrb_sym id;
+
+  mrb_get_args(mrb, "n", &id);
+  check_cv_name_sym(mrb, id);
+
+  val = mrb_iv_remove(mrb, mod, id);
+  if (!mrb_undef_p(val)) return val;
+
+  if (mrb_cv_defined(mrb, mod, id)) {
+    mrb_name_error(mrb, id, "cannot remove %S for %S",
+                   mrb_sym2str(mrb, id), mod);
+  }
+
+  mrb_name_error(mrb, id, "class variable %S not defined for %S",
+                 mrb_sym2str(mrb, id), mod);
+
+ /* not reached */
+ return mrb_nil_value();
+}
+
+/* 15.2.2.4.16 */
+/*
+ *  call-seq:
+ *     obj.class_variable_defined?(symbol)    -> true or false
+ *
+ *  Returns <code>true</code> if the given class variable is defined
+ *  in <i>obj</i>.
+ *
+ *     class Fred
+ *       @@foo = 99
+ *     end
+ *     Fred.class_variable_defined?(:@@foo)    #=> true
+ *     Fred.class_variable_defined?(:@@bar)    #=> false
+ */
+
+static mrb_value
+mrb_mod_cvar_defined(mrb_state *mrb, mrb_value mod)
+{
+  mrb_sym id;
+
+  mrb_get_args(mrb, "n", &id);
+  check_cv_name_sym(mrb, id);
+  return mrb_bool_value(mrb_cv_defined(mrb, mod, id));
+}
+
+/* 15.2.2.4.17 */
+/*
+ *  call-seq:
+ *     mod.class_variable_get(symbol)    -> obj
+ *
+ *  Returns the value of the given class variable (or throws a
+ *  <code>NameError</code> exception). The <code>@@</code> part of the
+ *  variable name should be included for regular class variables
+ *
+ *     class Fred
+ *       @@foo = 99
+ *     end
+ *     Fred.class_variable_get(:@@foo)     #=> 99
+ */
+
+static mrb_value
+mrb_mod_cvar_get(mrb_state *mrb, mrb_value mod)
+{
+  mrb_sym id;
+
+  mrb_get_args(mrb, "n", &id);
+  check_cv_name_sym(mrb, id);
+  return mrb_cv_get(mrb, mod, id);
+}
+
+/* 15.2.2.4.18 */
+/*
+ *  call-seq:
+ *     obj.class_variable_set(symbol, obj)    -> obj
+ *
+ *  Sets the class variable names by <i>symbol</i> to
+ *  <i>object</i>.
+ *
+ *     class Fred
+ *       @@foo = 99
+ *       def foo
+ *         @@foo
+ *       end
+ *     end
+ *     Fred.class_variable_set(:@@foo, 101)     #=> 101
+ *     Fred.new.foo                             #=> 101
+ */
+
+static mrb_value
+mrb_mod_cvar_set(mrb_state *mrb, mrb_value mod)
+{
+  mrb_value value;
+  mrb_sym id;
+
+  mrb_get_args(mrb, "no", &id, &value);
+  check_cv_name_sym(mrb, id);
+  mrb_cv_set(mrb, mod, id, value);
+  return value;
+}
+
+static mrb_value
+mrb_mod_included_modules(mrb_state *mrb, mrb_value self)
+{
+  mrb_value result;
+  struct RClass *c = mrb_class_ptr(self);
+  struct RClass *origin = c;
+
+  MRB_CLASS_ORIGIN(origin);
+  result = mrb_ary_new(mrb);
+  while (c) {
+    if (c != origin && c->tt == MRB_TT_ICLASS) {
+      if (c->c->tt == MRB_TT_MODULE) {
+        mrb_ary_push(mrb, result, mrb_obj_value(c->c));
+      }
+    }
+    c = c->super;
+  }
+
+  return result;
+}
+
+mrb_value mrb_class_instance_method_list(mrb_state*, mrb_bool, struct RClass*, int);
+
+/* 15.2.2.4.33 */
+/*
+ *  call-seq:
+ *     mod.instance_methods(include_super=true)   -> array
+ *
+ *  Returns an array containing the names of the public and protected instance
+ *  methods in the receiver. For a module, these are the public and protected methods;
+ *  for a class, they are the instance (not singleton) methods. With no
+ *  argument, or with an argument that is <code>false</code>, the
+ *  instance methods in <i>mod</i> are returned, otherwise the methods
+ *  in <i>mod</i> and <i>mod</i>'s superclasses are returned.
+ *
+ *     module A
+ *       def method1()  end
+ *     end
+ *     class B
+ *       def method2()  end
+ *     end
+ *     class C < B
+ *       def method3()  end
+ *     end
+ *
+ *     A.instance_methods                #=> [:method1]
+ *     B.instance_methods(false)         #=> [:method2]
+ *     C.instance_methods(false)         #=> [:method3]
+ *     C.instance_methods(true).length   #=> 43
+ */
+
+static mrb_value
+mrb_mod_instance_methods(mrb_state *mrb, mrb_value mod)
+{
+  struct RClass *c = mrb_class_ptr(mod);
+  mrb_bool recur = TRUE;
+  mrb_get_args(mrb, "|b", &recur);
+  return mrb_class_instance_method_list(mrb, recur, c, 0);
+}
+
+static void
+remove_method(mrb_state *mrb, mrb_value mod, mrb_sym mid)
+{
+  struct RClass *c = mrb_class_ptr(mod);
+  khash_t(mt) *h;
+  khiter_t k;
+
+  MRB_CLASS_ORIGIN(c);
+  h = c->mt;
+
+  if (h) {
+    k = kh_get(mt, mrb, h, mid);
+    if (k != kh_end(h)) {
+      kh_del(mt, mrb, h, k);
+      mrb_funcall(mrb, mod, "method_removed", 1, mrb_symbol_value(mid));
+      return;
+    }
+  }
+
+  mrb_name_error(mrb, mid, "method '%S' not defined in %S",
+                 mrb_sym2str(mrb, mid), mod);
+}
+
+/* 15.2.2.4.41 */
+/*
+ *  call-seq:
+ *     remove_method(symbol)   -> self
+ *
+ *  Removes the method identified by _symbol_ from the current
+ *  class. For an example, see <code>Module.undef_method</code>.
+ */
+
+static mrb_value
+mrb_mod_remove_method(mrb_state *mrb, mrb_value mod)
+{
+  mrb_int argc;
+  mrb_value *argv;
+
+  mrb_get_args(mrb, "*", &argv, &argc);
+  while (argc--) {
+    remove_method(mrb, mod, mrb_obj_to_sym(mrb, *argv));
+    argv++;
+  }
+  return mod;
+}
+
+static mrb_value
+mrb_mod_s_constants(mrb_state *mrb, mrb_value mod)
+{
+  mrb_raise(mrb, E_NOTIMP_ERROR, "Module.constants not implemented");
+  return mrb_nil_value();       /* not reached */
+}
+
+/* implementation of Module.nesting */
+mrb_value mrb_mod_s_nesting(mrb_state*, mrb_value);
+
+void
+mrb_mruby_metaprog_gem_init(mrb_state* mrb)
+{
+  struct RClass *krn = mrb->kernel_module;
+  struct RClass *mod = mrb->module_class;
+
+  mrb_define_method(mrb, krn, "global_variables", mrb_f_global_variables, MRB_ARGS_NONE()); /* 15.3.1.2.4 */
+  mrb_define_method(mrb, krn, "local_variables", mrb_local_variables, MRB_ARGS_NONE()); /* 15.3.1.3.28 */
+
+  mrb_define_method(mrb, krn, "singleton_class", mrb_singleton_class, MRB_ARGS_NONE());
+  mrb_define_method(mrb, krn, "instance_variable_defined?", mrb_obj_ivar_defined, MRB_ARGS_REQ(1)); /* 15.3.1.3.20 */
+  mrb_define_method(mrb, krn, "instance_variable_get", mrb_obj_ivar_get, MRB_ARGS_REQ(1)); /* 15.3.1.3.21 */
+  mrb_define_method(mrb, krn, "instance_variable_set", mrb_obj_ivar_set, MRB_ARGS_REQ(2)); /* 15.3.1.3.22 */
+  mrb_define_method(mrb, krn, "instance_variables", mrb_obj_instance_variables, MRB_ARGS_NONE()); /* 15.3.1.3.23 */
+  mrb_define_method(mrb, krn, "methods", mrb_obj_methods_m, MRB_ARGS_OPT(1)); /* 15.3.1.3.31 */
+  mrb_define_method(mrb, krn, "private_methods", mrb_obj_private_methods, MRB_ARGS_OPT(1)); /* 15.3.1.3.36 */
+  mrb_define_method(mrb, krn, "protected_methods", mrb_obj_protected_methods, MRB_ARGS_OPT(1)); /* 15.3.1.3.37 */
+  mrb_define_method(mrb, krn, "public_methods", mrb_obj_public_methods, MRB_ARGS_OPT(1)); /* 15.3.1.3.38 */
+  mrb_define_method(mrb, krn, "singleton_methods", mrb_obj_singleton_methods_m, MRB_ARGS_OPT(1)); /* 15.3.1.3.45 */
+  mrb_define_method(mrb, krn, "define_singleton_method", mod_define_singleton_method, MRB_ARGS_ANY());
+
+  mrb_define_method(mrb, mod, "class_variables", mrb_mod_class_variables, MRB_ARGS_NONE()); /* 15.2.2.4.19 */
+  mrb_define_method(mrb, mod, "remove_class_variable", mrb_mod_remove_cvar, MRB_ARGS_REQ(1)); /* 15.2.2.4.39 */
+  mrb_define_method(mrb, mod, "class_variable_defined?", mrb_mod_cvar_defined, MRB_ARGS_REQ(1)); /* 15.2.2.4.16 */
+  mrb_define_method(mrb, mod, "class_variable_get", mrb_mod_cvar_get, MRB_ARGS_REQ(1)); /* 15.2.2.4.17 */
+  mrb_define_method(mrb, mod, "class_variable_set", mrb_mod_cvar_set, MRB_ARGS_REQ(2)); /* 15.2.2.4.18 */
+  mrb_define_method(mrb, mod, "included_modules", mrb_mod_included_modules, MRB_ARGS_NONE()); /* 15.2.2.4.30 */
+  mrb_define_method(mrb, mod, "instance_methods", mrb_mod_instance_methods, MRB_ARGS_ANY()); /* 15.2.2.4.33 */
+  mrb_define_method(mrb, mod, "remove_method", mrb_mod_remove_method, MRB_ARGS_ANY()); /* 15.2.2.4.41 */
+  mrb_define_method(mrb, mod, "method_removed", mrb_f_nil, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, mod, "constants", mrb_mod_constants, MRB_ARGS_OPT(1)); /* 15.2.2.4.24 */
+  mrb_define_class_method(mrb, mod, "constants", mrb_mod_s_constants, MRB_ARGS_ANY()); /* 15.2.2.3.1 */
+  mrb_define_class_method(mrb, mod, "nesting", mrb_mod_s_nesting, MRB_ARGS_REQ(0)); /* 15.2.2.3.2 */
+}
+
+void
+mrb_mruby_metaprog_gem_final(mrb_state* mrb)
+{
+}
diff --git a/mrbgems/mruby-metaprog/test/metaprog.rb b/mrbgems/mruby-metaprog/test/metaprog.rb
new file mode 100644
index 000000000..587d00d6f
--- /dev/null
+++ b/mrbgems/mruby-metaprog/test/metaprog.rb
@@ -0,0 +1,303 @@
+
+assert('Kernel#instance_variable_defined?', '15.3.1.3.20') do
+  o = Object.new
+  o.instance_variable_set(:@a, 1)
+
+  assert_true o.instance_variable_defined?("@a")
+  assert_false o.instance_variable_defined?("@b")
+  assert_true o.instance_variable_defined?("@a"[0,2])
+  assert_true o.instance_variable_defined?("@abc"[0,2])
+end
+
+assert('Kernel#instance_variables', '15.3.1.3.23') do
+  o = Object.new
+  o.instance_eval do
+    @a = 11
+    @b = 12
+  end
+  ivars = o.instance_variables
+
+  assert_equal Array, ivars.class,
+  assert_equal(2, ivars.size)
+  assert_true ivars.include?(:@a)
+  assert_true ivars.include?(:@b)
+end
+
+assert('Kernel#methods', '15.3.1.3.31') do
+  assert_equal Array, methods.class
+end
+
+assert('Kernel#private_methods', '15.3.1.3.36') do
+  assert_equal Array, private_methods.class
+end
+
+assert('Kernel#protected_methods', '15.3.1.3.37') do
+  assert_equal Array, protected_methods.class
+end
+
+assert('Kernel#public_methods', '15.3.1.3.38') do
+  assert_equal Array, public_methods.class
+  class Foo
+    def foo
+    end
+  end
+  assert_equal [:foo], Foo.new.public_methods(false)
+end
+
+assert('Kernel#singleton_methods', '15.3.1.3.45') do
+  assert_equal singleton_methods.class, Array
+end
+
+assert('Kernel.local_variables', '15.3.1.2.7') do
+  a, b = 0, 1
+  a += b
+
+  vars = Kernel.local_variables.sort
+  assert_equal [:a, :b, :vars], vars
+
+  assert_equal [:a, :b, :c, :vars], Proc.new { |a, b|
+    c = 2
+    # Kernel#local_variables: 15.3.1.3.28
+    local_variables.sort
+  }.call(-1, -2)
+end
+
+assert('Kernel#define_singleton_method') do
+  o = Object.new
+  ret = o.define_singleton_method(:test_method) do
+    :singleton_method_ok
+  end
+  assert_equal :test_method, ret
+  assert_equal :singleton_method_ok, o.test_method
+end
+
+def labeled_module(name, &block)
+  Module.new do
+    (class <<self; self end).class_eval do
+      define_method(:to_s) { name }
+      alias_method :inspect, :to_s
+    end
+    class_eval(&block) if block
+  end
+end
+
+def labeled_class(name, supklass = Object, &block)
+  Class.new(supklass) do
+    (class <<self; self end).class_eval do
+      define_method(:to_s) { name }
+      alias_method :inspect, :to_s
+    end
+    class_eval(&block) if block
+  end
+end
+
+assert('Module#class_variable_defined?', '15.2.2.4.16') do
+  class Test4ClassVariableDefined
+    @@cv = 99
+  end
+
+  assert_true Test4ClassVariableDefined.class_variable_defined?(:@@cv)
+  assert_false Test4ClassVariableDefined.class_variable_defined?(:@@noexisting)
+end
+
+assert('Module#class_variable_get', '15.2.2.4.17') do
+  class Test4ClassVariableGet
+    @@cv = 99
+  end
+
+  assert_equal 99, Test4ClassVariableGet.class_variable_get(:@@cv)
+end
+
+assert('Module#class_variable_set', '15.2.2.4.18') do
+  class Test4ClassVariableSet
+    @@foo = 100
+    def foo
+      @@foo
+    end
+  end
+
+  assert_true Test4ClassVariableSet.class_variable_set(:@@cv, 99)
+  assert_true Test4ClassVariableSet.class_variable_set(:@@foo, 101)
+  assert_true Test4ClassVariableSet.class_variables.include? :@@cv
+  assert_equal 99, Test4ClassVariableSet.class_variable_get(:@@cv)
+  assert_equal 101, Test4ClassVariableSet.new.foo
+end
+
+assert('Module#class_variables', '15.2.2.4.19') do
+  class Test4ClassVariables1
+    @@var1 = 1
+  end
+  class Test4ClassVariables2 < Test4ClassVariables1
+    @@var2 = 2
+  end
+
+  assert_equal [:@@var1], Test4ClassVariables1.class_variables
+  assert_equal [:@@var2, :@@var1], Test4ClassVariables2.class_variables
+end
+
+assert('Module#constants', '15.2.2.4.24') do
+  $n = []
+  module TestA
+    C = 1
+  end
+  class TestB
+    include TestA
+    C2 = 1
+    $n = constants.sort
+  end
+
+  assert_equal [ :C ], TestA.constants
+  assert_equal [ :C, :C2 ], $n
+end
+
+assert('Module#included_modules', '15.2.2.4.30') do
+  module Test4includedModules
+  end
+  module Test4includedModules2
+    include Test4includedModules
+  end
+  r = Test4includedModules2.included_modules
+
+  assert_equal Array, r.class
+  assert_true r.include?(Test4includedModules)
+end
+
+assert('Module#instance_methods', '15.2.2.4.33') do
+  module Test4InstanceMethodsA
+    def method1()  end
+  end
+  class Test4InstanceMethodsB
+    def method2()  end
+  end
+  class Test4InstanceMethodsC < Test4InstanceMethodsB
+    def method3()  end
+  end
+
+  r = Test4InstanceMethodsC.instance_methods(true)
+
+  assert_equal [:method1], Test4InstanceMethodsA.instance_methods
+  assert_equal [:method2], Test4InstanceMethodsB.instance_methods(false)
+  assert_equal [:method3], Test4InstanceMethodsC.instance_methods(false)
+  assert_equal Array, r.class
+  assert_true r.include?(:method3)
+  assert_true r.include?(:method2)
+end
+
+assert 'Module#prepend #instance_methods(false)' do
+  bug6660 = '[ruby-dev:45863]'
+  assert_equal([:m1], Class.new{ prepend Module.new; def m1; end }.instance_methods(false), bug6660)
+  assert_equal([:m1], Class.new(Class.new{def m2;end}){ prepend Module.new; def m1; end }.instance_methods(false), bug6660)
+end
+
+assert('Module#remove_class_variable', '15.2.2.4.39') do
+  class Test4RemoveClassVariable
+    @@cv = 99
+  end
+
+  assert_equal 99, Test4RemoveClassVariable.remove_class_variable(:@@cv)
+  assert_false Test4RemoveClassVariable.class_variables.include? :@@cv
+end
+
+assert('Module#remove_method', '15.2.2.4.41') do
+  module Test4RemoveMethod
+    class Parent
+      def hello
+      end
+     end
+
+     class Child < Parent
+      def hello
+      end
+    end
+  end
+
+  assert_true Test4RemoveMethod::Child.class_eval{ remove_method :hello }
+  assert_true Test4RemoveMethod::Child.instance_methods.include? :hello
+  assert_false Test4RemoveMethod::Child.instance_methods(false).include? :hello
+end
+
+assert('Module.nesting', '15.2.2.2.2') do
+  module Test4ModuleNesting
+    module Test4ModuleNesting2
+      assert_equal [Test4ModuleNesting2, Test4ModuleNesting],
+                   Module.nesting
+    end
+  end
+  module Test4ModuleNesting::Test4ModuleNesting2
+    assert_equal [Test4ModuleNesting::Test4ModuleNesting2], Module.nesting
+  end
+end
+
+assert('Moduler#prepend + #instance_methods') do
+  bug6655 = '[ruby-core:45915]'
+  assert_equal(Object.instance_methods, Class.new {prepend Module.new}.instance_methods, bug6655)
+end
+
+assert 'Module#prepend + #singleton_methods' do
+  o = Object.new
+  o.singleton_class.class_eval {prepend Module.new}
+  assert_equal([], o.singleton_methods)
+end
+
+assert 'Module#prepend + #remove_method' do
+  c = Class.new do
+    prepend Module.new { def foo; end }
+  end
+  assert_raise(NameError) do
+    c.class_eval do
+      remove_method(:foo)
+    end
+  end
+  c.class_eval do
+    def foo; end
+  end
+  removed = nil
+  c.singleton_class.class_eval do
+    define_method(:method_removed) {|id| removed = id}
+  end
+  assert_nothing_raised('[Bug #7843]') do
+    c.class_eval do
+      remove_method(:foo)
+    end
+  end
+  assert_equal(:foo, removed)
+end
+
+assert 'Module#prepend + #included_modules' do
+  bug8025 = '[ruby-core:53158] [Bug #8025]'
+  mixin = labeled_module("mixin")
+  c = labeled_module("c") {prepend mixin}
+  im = c.included_modules
+  assert_not_include(im, c, bug8025)
+  assert_include(im, mixin, bug8025)
+  c1 = labeled_class("c1") {prepend mixin}
+  c2 = labeled_class("c2", c1)
+  im = c2.included_modules
+  assert_not_include(im, c1, bug8025)
+  assert_not_include(im, c2, bug8025)
+  assert_include(im, mixin, bug8025)
+end
+
+assert("remove_method doesn't segfault if the passed in argument isn't a symbol") do
+  klass = Class.new
+  assert_raise(TypeError) { klass.remove_method nil }
+  assert_raise(TypeError) { klass.remove_method 123 }
+  assert_raise(TypeError) { klass.remove_method 1.23 }
+  assert_raise(NameError) { klass.remove_method "hello" }
+  assert_raise(TypeError) { klass.remove_method Class.new }
+end
+
+assert('alias_method and remove_method') do
+  begin
+    Fixnum.alias_method :to_s_, :to_s
+    Fixnum.remove_method :to_s
+
+    assert_nothing_raised do
+      # segfaults if mrb_cptr is used
+      1.to_s
+    end
+  ensure
+    Fixnum.alias_method :to_s, :to_s_
+    Fixnum.remove_method :to_s_
+  end
+end
diff --git a/mrbgems/mruby-method/mrblib/kernel.rb b/mrbgems/mruby-method/mrblib/kernel.rb
index b2ebd45ea..2efc93f37 100644
--- a/mrbgems/mruby-method/mrblib/kernel.rb
+++ b/mrbgems/mruby-method/mrblib/kernel.rb
@@ -1,8 +1,9 @@
 module Kernel
   def singleton_method(name)
     m = method(name)
-    if m.owner != singleton_class
-      raise NameError, "undefined method `#{name}' for class `#{singleton_class}'"
+    sc = (class <<self; self; end)
+    if m.owner != sc
+      raise NameError, "undefined method `#{name}' for class `#{sc}'"
     end
     m
   end
diff --git a/mrbgems/mruby-method/test/method.rb b/mrbgems/mruby-method/test/method.rb
index b229a4560..eb5f48341 100644
--- a/mrbgems/mruby-method/test/method.rb
+++ b/mrbgems/mruby-method/test/method.rb
@@ -149,7 +149,7 @@ assert 'Method#source_location' do
   assert_equal [filename, lineno], klass.new.method(:find_me_if_you_can).source_location
 
   lineno = __LINE__ + 1
-  klass.define_singleton_method(:s_find_me_if_you_can) {}
+  class <<klass; define_method(:s_find_me_if_you_can) {}; end
   assert_equal [filename, lineno], klass.method(:s_find_me_if_you_can).source_location
 
   klass = Class.new { def respond_to_missing?(m, b); m == :nothing; end }
@@ -243,7 +243,7 @@ assert 'owner' do
 
   assert_equal(c, c.new.method(:foo).owner)
   assert_equal(c, c2.new.method(:foo).owner)
-  assert_equal(c.singleton_class, c2.method(:bar).owner)
+  assert_equal((class <<c; self; end), c2.method(:bar).owner)
 end
 
 assert 'owner missing' do
@@ -413,12 +413,14 @@ assert 'UnboundMethod#bind' do
   assert_equal(:meth, m.bind(1).call)
   assert_equal(:meth, m.bind(:sym).call)
   assert_equal(:meth, m.bind(Object.new).call)
-  sc = Class.new {
-    class << self
+  sc = nil
+  Class.new {
+    sc = class << self
       def foo
       end
+      self
     end
-  }.singleton_class
+  }
   assert_raise(TypeError) { sc.instance_method(:foo).bind([]) }
   assert_raise(TypeError) { Array.instance_method(:each).bind(1) }
   assert_kind_of Method, Object.instance_method(:object_id).bind(Object.new)
diff --git a/mrbgems/mruby-toplevel-ext/test/toplevel.rb b/mrbgems/mruby-toplevel-ext/test/toplevel.rb
index aebdd8b4b..26aae9a7d 100644
--- a/mrbgems/mruby-toplevel-ext/test/toplevel.rb
+++ b/mrbgems/mruby-toplevel-ext/test/toplevel.rb
@@ -16,8 +16,8 @@ assert('Toplevel#include') do
 
   self.include ToplevelTestModule2, ToplevelTestModule1
 
-  assert_true self.class.included_modules.include?( ToplevelTestModule1 )
-  assert_true self.class.included_modules.include?( ToplevelTestModule2 )
+  assert_true self.class.ancestors.include?( ToplevelTestModule1 )
+  assert_true self.class.ancestors.include?( ToplevelTestModule2 )
   assert_equal :foo, method_foo
   assert_equal :bar2, CONST_BAR
 end