anchor.diff:      : '`' | '~' | '!' | '@' 
       | '$' | '^' | '&' | '-'
       | '+' | '<' | '>' | '?' 
  -    | '*' | '=' | ':' | '|' 
  -    | '\\' | '/' 
  +    | '*' | '=' /*| ':' | '|' */
  +    | '\\' /*| '/' */
       ;
   
   
  
positive.code: {
      opName = null;
  }
  /*    : id:IDENTIFIER         {opName = id.getText();}
      | sym:NON_WORD_SYMBOL   {opName = sym.getText();}
      ;
  */
      : opName=name
      ;
  
  
negative.code:     : ignore=nonKeywordName
      ;
  
  /* Made this part of tightPattern's closedPattern production
  private consPattern
      : closedPattern COLONCOLON tightPattern
      ;*/
  
  private closedPattern
      : parenthesizedPattern
      | variablePattern
      | literalPattern
      | listPattern
      | recordPattern
      | wildcardPattern
      ;
  