code: function( buttonName, buttonLabel, commandName, styleDefiniton )
  		{
  			var style = new CKEDITOR.style( styleDefiniton );
  
  			editor.attachStyleStateChange( style, function( state )
  				{
  					!editor.readOnly && editor.getCommand( commandName ).setState( state );
  				});
  
  			editor.addCommand( commandName, new CKEDITOR.styleCommand( style ) );
  
  			editor.ui.addButton( buttonName,
  				{
  					label : buttonLabel,
  					command : commandName
  				});
  		}
docs: All buttons use the same code to register. So, to avoid duplications, let's use this tool function.