: INTERPRET
    BEGIN
    WORD DUP C@ EOT? IF DROP EXIT THEN
    (find)
    NOT IF (parse) ELSE EXECUTE THEN
    C<? NOT IF LIT< (ok) (find) IF EXECUTE THEN THEN
    AGAIN ;

( Drop RSP until I-2 == INTERPRET. )
: EXIT!
    ['] INTERPRET       ( I )
    BEGIN               ( I )
    DUP                 ( I I )
    R> DROP I 2- @      ( I I a )
    = UNTIL
    DROP ;