anchor.diff:  fragment NO_RE      : ~[ \t\/];
   fragment ALPHABET   : ~('\t' | ' ' | '/' | '*' | '?' | '+' | '{' | '}' | '[' | ']'
                       | '(' | ')' | '|' | '"' | ',' | ':' | '\'' | '\\' | '!' | '=' | '~' | '&' | '^' | '<' | '>' );
  +fragment ALPHA		: [a-zA-Z];
   DIGIT				: [0-9];
  -NUMBER              : [0-9]+;
  +
  +DATE
  +: DIGIT DIGIT DIGIT DIGIT (DASH DIGIT DIGIT (DASH DIGIT DIGIT)?)?
  +;
   
   NL                  : [\r\n] -> skip;
   ws                  : WS+;
   
  -WORD                : ALPHABET+;
  -
  +WORD                : ALPHABET* ALPHA ALPHABET*;  // needs to have at least one alphabetical letter
   
   /*
    * Regular expressions
  
positive.code: ;
  
  date
  : DIGIT DIGIT DIGIT DIGIT  (DASH DIGIT DIGIT (DASH DIGIT DIGIT)?)?
  ;
  
  operator
  
negative.code: key
  : WORD
  | regex
  ;
  
  foundry
  