anchor.diff:  erlang_class -> class_name oo_definitions class_attributes class_methods
   		: ['$1', '$2', '$3', '$4'].
   
  -oo_definitions -> class_exports 				oo_definitions: ['$1'].
  +oo_definitions -> class_exports				: ['$1'].
   
   oo_definitions -> class_exports class_constructor 	: ['$1', '$2'].
   oo_definitions -> class_constructor class_exports  	: ['$1', '$2'].
   
  -oo_definitions -> class_extends class_constructor 	: ['$1', '$2'].
  -oo_definitions -> class_constructor class_extends  	: ['$1', '$2'].
  -
  -oo_definitions -> class_import class_constructor 	: ['$1', '$2'].
  -oo_definitions -> class_constructor class_import  	: ['$1', '$2'].
  -
  -oo_definitions -> class_exports class_import 		: ['$1', '$2'].
  -oo_definitions -> class_import class_exports  		: ['$1', '$2'].
  +oo_definitions -> class_extends class_exports	 	: ['$1', '$2'].
  +oo_definitions -> class_exports class_extends  		: ['$1', '$2'].
  +
  +oo_definitions -> class_import class_exports 		: ['$1', '$2'].
  +oo_definitions -> class_exports class_import  		: ['$1', '$2'].
   
   oo_definitions -> class_exports class_constructor class_extends
   		: ['$1', '$2', '$3'].
  
positive.code: argument_list -> argument					: ['$1'].
  argument_list -> argument ',' argument_list	: ['$1' |'$3'].
  
  argument -> tuple								:'$1'.
  argument -> list								:'$1'.
  argument -> erlang_argument 					:'$1'.
  argument -> identifier							:unwrap('$1').
  argument -> identifier '(' ')'					:unwrap('$1').
  argument -> identifier '(' argument_list ')' 	:{unwrap('$1'), '$3'}.
  
  
negative.code: 
  oo_new_statement -> 
  	identifier '=' identifier '::' add_expr:
  	{oo_new, {unwrap('$1'), unwrap('$3'), '$5'}}.
  oo_set_statement -> 
  	identifier '::' identifier '=' add_expr:
  	{oo_set, {unwrap('$1'), unwrap('$3'), '$5'}}.
  oo_get_statement -> 
  	identifier '::' add_expr:
  	{oo_get, {unwrap('$1'), '$3'}}.
  
  add_expr -> mult_expr '+' add_expr	: {'+', '$1', '$3'}.
  add_expr -> mult_expr '-' add_expr	: {'-', '$1', '$3'}.
  add_expr -> mult_expr			: '$1'.
  
  mult_expr -> modulus_expr '*' mult_expr	:{'*', '$1', '$3'}.
  mult_expr -> modulus_expr '/' mult_expr	:{'/', '$1', '$3'}.
  mult_expr -> modulus_expr		: '$1'.
  
  modulus_expr -> unary_expr 'rem' modulus_expr	:{'rem', '$1', '$3'}.
  modulus_expr -> unary_expr			: '$1'.
  
  unary_expr -> '-' argument	: {'-', '$2'}.
  unary_expr -> argument		: '$1'.
  