anchor.diff:              |   Wire
               |   Wand
               |   Wor
  -            |   None
  +            |   NONE
               ;
   
   drive_strength  :   Open_parenthesis drive_strength_value_0 Comma drive_strength_value_1 Close_parenthesis ;
  
positive.code: fragment
  DIGIT : [0-9] ;
  
  //Broken_string_literal : '"' ('\\' [\\"nt\[\]\|] | ~[\\"\r\n])* '\n' ;
  Dollar_Identifier : '$' [a-zA-Z0-9_$] [a-zA-Z0-9_$]* ;
  Escaped_identifier : '\\' ~[ \r\t\n]* ;
  Simple_identifier : ALPHA (ALPHA | DIGIT)* ;
  String_literal : '"' ('\\' [\\"nt\[\]\|] | ~[\\"\r\n])* '"' ;
  
  
  // punctuation
  
negative.code: Nand : 'nand' ;
  Negedge : 'negedge' ;
  Nmos : 'nmos' ;
  NONE : 'none' ;
  Nor : 'nor' ;
  Not : 'not' ;
  Notif0 : 'notif0' ;
  