anchor.diff:  box_expression:
           '@''('conditional_expression')' |
           '@'constant;
  -block_parameters: '(' (type_variable_declarator | 'void')? (',' type_variable_declarator)* ')';
  +block_parameters: '(' (type_variable_declarator | type_name | 'void')? (',' (type_variable_declarator | type_name))* ')';
   
   block_expression:'^' type_specifier? block_parameters? compound_statement;
   
  
positive.code: IF            : 'if';
  IN            : 'in';
  INOUT         : 'inout';
  GOTO          : 'goto';
  INT           : 'int';
  LONG          : 'long';
  
negative.code: generics_specifier: '<' (type_specifier)? (',' type_specifier)*'>' ;
  
  type_specifier:
  'void' | 'char' | 'short' | 'int' | 'long' | 'float' | 'double' | 'signed' | 'unsigned' | 'instancetype'
  	|	('id' ( protocol_reference_list )? )
  	|	(class_name ( protocol_reference_list | generics_specifier )?)
  	|	struct_or_union_specifier
  