anchor.diff:  
   struct_add
   @init {
  -    int has_ver1 = 0;
  -    int has_ver2 = 0;
  -    int has_cond = 0;
  +    bool has_ver1 = false;
  +    bool has_ver2 = false;
  +    bool has_cond = false;
  +    bool has_vercond = false;
   }
       :   TAG_START_ADD
           ( name=attr_variable_name
           | type=attr_type_type
  -        | {has_ver1=1;} ver1=attr_expression_ver1
  -        | {has_ver2=1;} ver2=attr_expression_ver2
  -        | {has_cond=1;} cond=attr_expression_cond
  +        | {has_ver1=true;} ver1=attr_expression_ver1
  +        | {has_ver2=true;} ver2=attr_expression_ver2
  +        | {has_cond=true;} cond=attr_expression_cond
  +        | {has_vercond=true;} vercond=attr_expression_vercond
           | attr_expression_default
           | anyattribute
           )*
  
positive.code: 
  attr_expression_cond
      :   NAME_COND! ATTR_EQ! ATTR_VALUE_START! expression ATTR_VALUE_END!
      ;
  
  attr_expression_default
  
negative.code:     :   { tagMode && !attrMode }?=> 'cond'
      ;
  
  NAME_VERCOND
      :   { tagMode && !attrMode }?=> 'vercond'
      ;
  
  NAME_DEFAULT
      :   { tagMode && !attrMode }?=> 'default'
      ;
  