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.

mrbgems/default.gembox

 MRuby::GemBox.new do |conf|
+  # Meta-programming features
+  conf.gem :core => "mruby-metaprog"
+
   # Use standard IO/File class
   conf.gem :core => "mruby-io"
 

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

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?

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)}

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

mrbgems/mruby-metaprog/mrbgem.rake

+MRuby::Gem::Specification.new('mruby-metaprog') do |spec|
+  spec.license = 'MIT'
+  spec.author  = 'mruby developers'
+  spec.summary = 'Meta-programming features for mruby'
+end

mrbgems/mruby-metaprog/test/metaprog.rb

+
+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

mrbgems/mruby-method/mrblib/kernel.rb

 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

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)

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

src/etc.c

@@ -75,6 +75,7 @@ mrb_obj_to_sym(mrb_state *mrb, mrb_value name)
       if (mrb_nil_p(name)) {
         name = mrb_inspect(mrb, name);
         mrb_raisef(mrb, E_TYPE_ERROR, "%S is not a symbol", name);
+        /* not reached */
       }
       /* fall through */
     case MRB_TT_STRING:

test/t/class.rb

@@ -36,7 +36,7 @@ end
 
 assert('Class#new', '15.2.3.3.3') do
   assert_raise(TypeError, 'Singleton should raise TypeError') do
-    "a".singleton_class.new
+    (class <<"a"; self; end).new
   end
 
   class TestClass
@@ -293,15 +293,7 @@ assert('singleton tests') do
     end
   end
 
-  assert_false baz.singleton_methods.include? :run_foo_mod
-  assert_false baz.singleton_methods.include? :run_baz
-
-  assert_raise(NoMethodError, 'should raise NoMethodError') do
-    baz.run_foo_mod
-  end
-  assert_raise(NoMethodError, 'should raise NoMethodError') do
-    baz.run_baz
-  end
+  assert_equal :run_baz, baz
 
   assert_raise(NoMethodError, 'should raise NoMethodError') do
     bar.run_foo_mod
@@ -318,8 +310,8 @@ assert('singleton tests') do
     self
   end
 
-  assert_true baz.singleton_methods.include? :run_baz
-  assert_true baz.singleton_methods.include? :run_foo_mod
+  assert_true baz.respond_to? :run_baz
+  assert_true baz.respond_to? :run_foo_mod
   assert_equal 100, baz.run_foo_mod
   assert_equal 300, baz.run_baz
 
@@ -440,12 +432,3 @@ assert('class with non-class/module outer raises TypeError') do
   assert_raise(TypeError) { class 0::C1; end }
   assert_raise(TypeError) { class []::C2; end }
 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

test/t/codegen.rb

@@ -194,4 +194,4 @@ assert('register window of calls (#3783)') do
       alias send2 send
     end
   end
-end
\ No newline at end of file
+end

test/t/kernel.rb

@@ -103,7 +103,7 @@ assert('Kernel#__send__', '15.3.1.3.4') do
   # test with argument
   assert_true __send__(:respond_to?, :nil?)
   # test without argument and without block
-  assert_equal  Array, __send__(:public_methods).class
+  assert_equal String, __send__(:to_s).class
 end
 
 assert('Kernel#block_given?', '15.3.1.3.6') do
@@ -278,30 +278,6 @@ assert('Kernel#inspect', '15.3.1.3.17') do
   assert_equal "main", s
 end
 
-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#is_a?', '15.3.1.3.24') do
   assert_true is_a?(Kernel)
   assert_false is_a?(Array)
@@ -381,10 +357,6 @@ assert('Kernel#method_missing', '15.3.1.3.30') do
   end
 end
 
-assert('Kernel#methods', '15.3.1.3.31') do
-  assert_equal Array, methods.class
-end
-
 assert('Kernel#nil?', '15.3.1.3.32') do
   assert_false nil?
 end
@@ -408,23 +380,6 @@ end
 
 # Kernel#print is defined in mruby-print mrbgem. '15.3.1.3.35'
 
-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
-
 # Kernel#puts is defined in mruby-print mrbgem. '15.3.1.3.39'
 
 assert('Kernel#raise', '15.3.1.3.40') do
@@ -496,46 +451,13 @@ assert('Kernel#send', '15.3.1.3.44') do
   # test with argument
   assert_true send(:respond_to?, :nil?)
   # test without argument and without block
-  assert_equal send(:public_methods).class, Array
-end
-
-assert('Kernel#singleton_methods', '15.3.1.3.45') do
-  assert_equal singleton_methods.class, Array
+  assert_equal send(:to_s).class, String
 end
 
 assert('Kernel#to_s', '15.3.1.3.46') do
   assert_equal to_s.class, String
 end
 
-assert('Kernel#to_s on primitives') 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
-
-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#!=') do
   str1 = "hello"
   str2 = str1
@@ -585,15 +507,6 @@ assert('Kernel#global_variables') do
   end
 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
-
 assert('stack extend') do
   def recurse(count, stop)
     return count if count > stop