anchor.diff:      |   expression ('+'|'-') expression
       |   expression ('<' '<' | '>' '>' '>' | '>' '>') expression
       |   expression ('<=' | '>=' | '>' | '<') expression
  -    |   expression 'is' type
  -    |   expression ('==' | '!=') expression
  -    |   expression DOTS expression
  -    |   expression '&' expression
  -    |   expression '^' expression
  -    |   expression '|' expression
  -    |   expression '&&' expression
  -    |   expression '||' expression
  -    |   expression '?' expression ':' expression
  +    |   expression IS type
  +    |   expression (EQ | NE) expression
  +    |   expression RANGE expression
  +    |   expression BITAND expression
  +    |   expression CARET expression
  +    |   expression PIPE expression
  +    |   expression AND expression
  +    |   expression OR expression
  +    |   expression QUESTION expression ':' expression
       |   expression
           (   '='<assoc=right>
           |   '+='<assoc=right>
  
positive.code: WITH    :   'with';
  WHILE   :   'while';
  
  // §3.10.1 Integer Literals
  
  IntegerLiteral
  
negative.code: call
      :   (   Identifier
          |   '(' func ')'
          )
          '(' params ')'
      ;
  
  params
  