( Drop RSP until I-2 == INTERPRET. )
: EXIT!
    ['] INTERPRET       ( I )
    BEGIN               ( I )
    DUP                 ( I I )
    R> DROP I 2- @     ( I I a )
    = UNTIL
    DROP
;
: (ok) SPC ." ok" NL ;
: (uflw) ABORT" stack underflow" ;
: (wnf) (print) SPC ABORT" word not found" ;