Renaming Vool exppressions rightly

Class, Method and Lambda (was block) are expressions.
Just making things clearer, especially for the blocks (ahem, lambdas) is matters.
wip

test/ruby/helper.rb

@@ -29,13 +29,13 @@ module Ruby
       @vool.body.statements.last
     end
     def test_class
-      assert_equal Vool::ClassStatement , @vool.class
+      assert_equal Vool::ClassExpression , @vool.class
     end
     def test_body
       assert_equal Vool::Statements , @vool.body.class
     end
     def test_getter
-      assert_equal Vool::MethodStatement , getter.class
+      assert_equal Vool::MethodExpression , getter.class
     end
     def test_getter_return
       assert_equal Vool::ReturnStatement , getter.body.class

test/ruby/test_class_method_statement.rb

@@ -18,7 +18,7 @@ module Ruby
       input = "def self.tryout(arg) ; arg = true ; return arg ; end "
       @str = compile( input ).to_s
       assert @str.include?("def self.tryou"), @str
-      assert @str.include?("arg = true"), @str      
+      assert @str.include?("arg = true"), @str
     end
   end
   class TestClassMethodStatement2 < MiniTest::Test
@@ -43,7 +43,7 @@ module Ruby
       @lst = compile( input ).to_vool
     end
     def test_method
-      assert_equal Vool::ClassMethodStatement , @lst.class
+      assert_equal Vool::ClassMethodExpression , @lst.class
     end
     def test_method_args
       assert_equal [:arg1, :arg2] , @lst.args

test/ruby/test_class_statement.rb

@@ -9,7 +9,7 @@ module Ruby
       @vool = compile( input ).to_vool
     end
     def test_class
-      assert_equal Vool::ClassStatement , @vool.class
+      assert_equal Vool::ClassExpression , @vool.class
     end
     def test_body
       assert_equal Vool::Statements , @vool.body.class

test/ruby/test_class_statement2.rb

@@ -12,7 +12,7 @@ module Ruby
       assert_equal 2 , @vool.body.length , "setter, getter"
     end
     def test_setter
-      assert_equal Vool::MethodStatement , setter.class
+      assert_equal Vool::MethodExpression , setter.class
     end
     def test_setter_assign
       assert_equal Vool::Statements , setter.body.class

test/ruby/test_class_statement3.rb

@@ -11,7 +11,7 @@ module Ruby
       assert_equal 4 , @vool.body.length , "2 setters, 2 getters"
     end
     def test_setter
-      assert_equal Vool::MethodStatement , setter.class
+      assert_equal Vool::MethodExpression , setter.class
     end
     def test_setter_assign
       assert_equal Vool::Statements , setter.body.class

test/ruby/test_ruby_block_statement.rb

@@ -38,7 +38,7 @@ module Ruby
     def test_first
       assert_equal Vool::LocalAssignment , @lst.first.class
       assert @lst.first.name.to_s.start_with?("implicit_block_")
-      assert_equal Vool::LambdaStatement , @lst.first.value.class
+      assert_equal Vool::LambdaExpression , @lst.first.value.class
     end
     def test_last_send
       assert_equal 2 , @lst.length

test/ruby/test_ruby_block_statement1.rb

@@ -41,7 +41,7 @@ module Ruby
       assert @lst.first.first.name.to_s.start_with?("implicit_block")
     end
     def test_block_assign_right
-      assert_equal Vool::LambdaStatement , @lst.first.first.value.class
+      assert_equal Vool::LambdaExpression , @lst.first.first.value.class
     end
     def test_a_assign
       assert_equal Vool::LocalAssignment , @lst.first.last.class

test/ruby/test_variables.rb

@@ -55,8 +55,8 @@ module Ruby
   class TestVariablesVool < MiniTest::Test
     include RubyTests
     def test_local_basic
-      lst = compile( "foo = 1 ; foo").to_vool
-      assert_equal Vool::LocalVariable , lst.statements[1].class
+      lst = compile( "foo = 1 ; return foo").to_vool
+      assert_equal Vool::LocalVariable , lst.statements[1].return_value.class
     end
 
     def test_instance_basic