anchor.diff:  	: gate_instance_identifier range_?
   	;
   
  -// 3.2 Primitive strengths
  +// A.3.2 Primitive strengths
   
   pulldown_strength
   	: '(' strength0 ',' strength1 ')'
  
positive.code: 	: attribute_instance* '.' port_identifier '(' expression? ')'
  	;
  
  // 4.2 Generate construct
  
  generate_region
  	: 'generate' module_or_generate_item* 'endgenerate'
  
negative.code: 	| 'for' '(' variable_assignment ';' expression ';' variable_assignment ')' statement
  	;
  
  // A.6.9 Task enable statements
  
  system_task_enable
  	: system_task_identifier ('(' expression? (',' expression?)* ')')? ';'
  