diff --git a/.rubocop.yml b/.rubocop.yml
index 3d98fc8..0bb63a8 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -41,3 +41,6 @@ Documentation:
 
 Rails:
   Enabled: true
+
+Metrics/ClassLength:
+  Max: 150
diff --git a/lib/easydsl/node.rb b/lib/easydsl/node.rb
index eedb9d9..9caf895 100644
--- a/lib/easydsl/node.rb
+++ b/lib/easydsl/node.rb
@@ -3,11 +3,12 @@
 
 module Easydsl
   class Node
-    attr_reader :name, :index, :parent
+    attr_reader :name, :index, :parent, :singleton
     attr_accessor :args
 
     def initialize(name, args, index, parent, node_builders = [])
-      @name = name
+      @name = name.to_s.chomp('!').to_sym
+      @singleton = name[-1] == '!'
       @args = args
       @index = index
       @parent = parent
@@ -30,23 +31,41 @@ def max_index
       all_nodes.map(&:index).max || 0
     end
 
+    def define(&block)
+      add_block(&block)
+    end
+
+    protected
+
+    def add_hierarchy(to, tree, base_index)
+      tree.each_with_index do |item, index|
+        to.add_child(item.name, item.args, base_index + index, to, item.nodes)
+      end
+    end
+
     def add_block(&block)
       tree = NodeBuilder.new('tree')
       tree.instance_exec(&block)
-      base_index = max_index
-      tree.nodes.each_with_index do |item, index|
-        add_child(item.name, item.args, base_index + index, item.nodes)
-      end
+      add_hierarchy(self, tree.nodes, max_index)
     end
 
-    protected
-
     def add_child(name, args, index, parent, node_builders = [])
+      node = handle_singleton(name, args, node_builders)
+      return node unless node.nil?
       node = Node.new(name, args, index, parent, node_builders)
       nodes[node.name] << node
       node
     end
 
+    def handle_singleton(name, args, node_builders = [])
+      return nil unless nodes.key?(name)
+      node = nodes[name].first
+      return nil if node.nil? || node.singleton == false
+      node.args = args
+      add_hierarchy(node, node_builders, node.max_index)
+      nodes[name].first
+    end
+
     def clean_method_symbol(method_symbol)
       method_symbol.to_s.gsub(/[=?]/, '').to_sym
     end
diff --git a/lib/easydsl/version.rb b/lib/easydsl/version.rb
index 62c6917..f93b09d 100644
--- a/lib/easydsl/version.rb
+++ b/lib/easydsl/version.rb
@@ -1,3 +1,3 @@
 module Easydsl
-  VERSION = '0.1.0'.freeze
+  VERSION = '0.1.1'.freeze
 end
diff --git a/spec/easydsl_spec.rb b/spec/easydsl_spec.rb
index b131382..cd7b766 100644
--- a/spec/easydsl_spec.rb
+++ b/spec/easydsl_spec.rb
@@ -86,6 +86,12 @@ class Post
     it 'returns the first element if multiple present' do
       expect(dsl.navbar).not_to be_nil
     end
+
+    it 'returns the value if called directly' do
+      node = dsl.config.title
+      expect(node).to eq('test title')
+      expect(dsl.config.title).to eq('test title')
+    end
   end
 
   context 'Members override' do
diff --git a/spec/operators_spec.rb b/spec/operators_spec.rb
index 547aef2..209730b 100644
--- a/spec/operators_spec.rb
+++ b/spec/operators_spec.rb
@@ -57,7 +57,7 @@
 
       it 'set a block to root' do
         expect do
-          dsl.add_block do
+          dsl.define do
             item 'item 3'
           end
         end.to change {
@@ -118,6 +118,51 @@
     end
   end
 
+  context 'Operator !' do
+    let(:dsl) do
+      Easydsl.define do
+        config! :hello do
+          title! 'test'
+          environment :debug
+        end
+        item do
+          layout :left
+        end
+        item
+      end
+    end
+
+    it 'set singleton flags correctly' do
+      expect(dsl.config.singleton).to be(true)
+      expect(dsl.item.singleton).to be(false)
+    end
+
+    it 'modify the existing root node' do
+      dsl.define do
+        config do
+          title 'changed'
+          new_property 'hello'
+        end
+      end
+      expect(dsl.configs.count).to eq(1)
+      expect(dsl.config.nodes.count).to eq(3)
+      expect(dsl.config.title).to eq('changed')
+      expect(dsl.config.environment).to eq(:debug)
+      expect(dsl.config.new_property).to eq('hello')
+    end
+
+    it 'modify the existing nested node' do
+      expect(dsl.config.nodes.count).to eq(2)
+      expect(dsl.config.title).to eq('test')
+      dsl.config do
+        title 'changed'
+      end
+      expect(dsl.config.nodes.count).to eq(2)
+      expect(dsl.config.title).to eq('changed')
+      expect(dsl.config.environment).to eq(:debug)
+    end
+  end
+
   context 'Operator ?' do
     let(:dsl) do
       Easydsl.define do