anchor.diff:  	;
   
   ifdef_group_of_lines
  -	: non_port_module_item*
  +	: (non_port_module_item | statement | conditional_compilation_directive)*
   	;
   
   ifndef_group_of_lines
  -	: non_port_module_item*
  +	: (non_port_module_item | statement | conditional_compilation_directive)*
   	;
   
   elsif_group_of_lines
  -	: non_port_module_item*
  +	: (non_port_module_item | statement | conditional_compilation_directive)*
   	;
   
   else_group_of_lines
  -	: non_port_module_item*
  +	: (non_port_module_item | statement | conditional_compilation_directive)*
   	;
   
   // 19.5 `include
  
positive.code: 	| endkeywords_directive
  	;
  
  post_module_compiler_directive
  	: endcelldefine_compiler_directive
  	| default_nettype_compiler_directive
  	| undefine_compiler_directive
  	| resetall_compiler_directive
  	| nounconnected_drive_compiler_directive
  	;
  
  // 19.1 `celldefine and `endcelldefine
  
negative.code: 	| specify_block
  	| attribute_instance* parameter_declaration ';'
  	| attribute_instance* specparam_declaration
  	| in_module_compiler_directive
  	;
  
  parameter_override
  